Is MGW Network Configuration

DD

Network configurationMedia Gateway – Integrated Site

Service guide

14/154 43-CNA 113 061 UenRev PA43

2006-11-08

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Template ID: 12/002 01-AZE 101 01+ Uen Rev A (variable)

Prepared: EAB/AUN/DAV Per Ferngren (etxpefe)

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Document responsible: EAB/AUN/DAV Arne Nordlund (etxarnd)

Latest change date: 2006-11-08 17:29:39 (updates automatically on save)

File name: 14_15443-CNA113061Uen.fm

CDOC inspection record: 24/1776-CNA 113 061 Uen

Revision history

Revision Date Name What

PA1-3 2006-06-14 etxpefe Created document

PA4-10 2006-06-21 etxpefe More updates.

PA14-16 2006-08-02 etxpefe More updates

PA17 2006-08-21 etxpefe Fixed for release

PA18-19 2006-08-22 etxpefe Updates after 2/3 review TM-APP 2006-08-22

PA20-21 2006-09-04 etxpefe Removed SPCs from MGW 1.0 CDOC and changedIS CoS mappings to IS 1.1 Traffic Class scheme

PA22-23 2006-09-11 etxpefe Added text about DSCP to p-bit mapping in ISER.Added restriction on 4 SNS for H.248

Network configuration

PA24-25 2006-09-14 etxpefe Changed names: Prefix -> Subnet address + initiatedchanges for new address allocation for H.248

PA26 2006-09-25 etxpefe Continued updates. Changed address allocation forH.248 to let the ISER use the last addresses insegments

PA27 2006-10-04 etxpefe Fixed format errors for release

PA28-30 2006-10-04 etxpefe Updated after TM-APP final review.

PA31 2006-10-13 qtxhanr Edited

PA32-35 2006-10-16 etxpefe Fixed for release

PA36 2006-10-24 etxpefe Added tags to attributes

PA37-38 2006-10-25 etxpefe Minor updates

PA39 2006-10-30 etxpefe Sorted attributes for GUI in alphabetical order

PA40 2006-11-06 eleberg Explained about opState relation to admState

PA41 2006-11-06 etxpefe Added opState explanation for nexthop

PA42-43 2006-11-08 etxpefe Minor modification to IP interface counters andupdates of the ARP parameters.

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Copyright

© 2006 Ericsson AB – All rights reservedNo part of this document may be reproduced in any form withoutthe written permission of the copyright owner.

Disclaimer

The contents of this document are subject to revision withoutnotice due to continued progress in methodology, design, andmanufacturing. Ericsson shall have no liability for any error ordamage of any kind resulting from the use of this document.

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Contents

1 General information ............................................. 71.1 Scope ............................................................................. 7

1.2 Audience ......................................................................... 7

1.3 Related documents ......................................................... 7

2 Overview ............................................................... 82.1 Network configuration for an MGW ................................. 8

2.2 VLAN and subnet configuration details .......................... 9

2.3 Special IP address configuration cases ........................ 12

2.4 IS configuration ............................................................. 13

2.5 Configuration of ISER ................................................... 20

3 The Network Configuration service .................. 233.1 IP interface configuration .............................................. 23

3.2 Next hop configuration .................................................. 25

3.3 Static route configuration .............................................. 26

3.4 Virtual router ................................................................. 28

3.5 ARP parameters ........................................................... 28

3.6 Media supervision ......................................................... 29

3.7 H.248 route configuration ............................................. 29

3.8 SCTP parameters ......................................................... 30

4 GUI objects ......................................................... 334.1 IP interface .................................................................... 33

4.2 Next hop ....................................................................... 36

4.3 Route ............................................................................ 38

4.4 Virtual router ................................................................. 39

4.5 ARP parameters ........................................................... 39

4.6 Media supervision ......................................................... 40

4.7 H.248 route ................................................................... 40

4.8 SCTP parameters ......................................................... 41

5 Acronyms and abbreviations ............................ 44

6 Terms and expressions ...................................... 46

7 References .......................................................... 49

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1 General information

1.1 ScopeThis document describes the Network Configuration service in the Media Gateway(MGW) Management Functional Area (MFA). The document provides informationand instructions for IP network-related configuration for the MGW in the IntegratedSite (IS).

1.2 AudienceThe document is primarily aimed at operators and people responsible forconfiguration and maintenance of the Media Gateway (MGW) system in theIntegrated Site (IS).

1.3 Related documentsSuggested reading or reference:

• The ISM user interface, Ref. [1]

• Management function area guide (MFAG): Integrated Site Services, Ref. [2]

• Service Guide (SG), IS services: Network configuration, Ref. [3]

• MFAG: Media Gateway, Ref. [4]

• MFAG: ISER, Ref. [5]

• SG: Virtual media gateway, Ref. [7]

• Operation Procedure Instruction (OPI) for MGW: Configuring the IS network,Ref. [8].

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2 Overview

2.1 Network configuration for an MGW

Figure 1 Subnet configuration example for media and H.248 signaling for an MGW

Call Handling blade

(internal media)

(external media)

Media addresses:

VR

Corenetwork

ISER

IS

VR

= Subnet or subnet-segment addresses

= IP interface (H.248)

= IP interface (media)

= Physical Ethernet interface

= Virtual Router

H.248 addresses:

MGW

Stand-by blade

H.248subnet/VLAN

Externalmediasubnet/VLAN

InternalmediaSubnet/VLAN

= Next hop (media)

= Next hop (H.248)

advertised to IS-external network

GC

= Media Gateway = Gateway Controller

Note: The Gateway Controller (GC) may be located either within or outside of the IS site.If the GC is located externally of the IS site, an H.248 route must be configured in the MGW.

TDM (SDH/SONET) interface

TDM (SDH/SONET) interface

TDM (E1) interface

TDM (E1) interface

GCMGW

GC

141.0.1.124

131.0.0.1

141.0.1.1

10.0.3.0

131.0.0.4

(internal media)

(external media)

10.0.3.1

131.0.0.5

(internal media)

(external media)

10.0.15.1

131.0.0.7

(internal media)

(external media)

10.0.15.0

131.0.0.6

VR

Next hopaddresses:

Media addresses:

141.0.1.129

Static route: x.y.z.w/m via next hop 131.0.0.1 (this is used for media transport to an external MGW)

H.248 route: a.b.c.d/e via next hop 141.0.1.124

a.b.c.d/e

MGWx.y.z.w/m

External MGW

External GC

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Figure 1 above shows an example of the subnet and IP address configuration for anMGW blade system.

The MGW communicates with the core network (the IP Multimedia Subsystem (IMS)core network). For media transport to and from the core network a dedicated ISVLAN (virtual local area network) and subnet is used. For the external media subnetat least one Next hop and one Static Route must be configured to enable mediatransport to the core network. For media you must also configure IP interfaces(media addresses) at the external media VLAN for each physical Ethernet interfaceof the MGW blades. Note that both blades of the MGW must have separate IPinterfaces (IP addresses) for external media transport, since both blades need tosupport media transport to the core network.

A separate IS VLAN is used for internal media transport, that is, for media transportbetween the blades of the MGW. The IP addresses used for internal media transportare automatically assigned by the MGW software and are based on the subrack andslot position of each blade (see Section 2.2). The internal media VLAN is, forexample, used for TDM to TDM calls when the TDM resources are located ondifferent blades in the MGW.

In addition, a separate IS VLAN and subnet is used for the H.248 signaling betweenthe gateway controller (GC) and the MGW blade system. The gateway controller(dashed in the figure) may be located either inside or outside of the IS. An H.248Route is used to direct the H.248 signaling via the ISER.

In the MGW there are two IP interfaces per blade pair for H.248 signaling. That is,when you create the first Virtual media gateway using the Stream ControlTransmission Protocol (SCTP), two H.248 IP interfaces will be created automatically.The IP addresses used for H.248 IP interfaces are allocated from the subnetsegments for H.248 that are specified in Table 2 and in Section 2.4.3. If you createadditional virtual media gateways, that terminate the H.248 signaling on the sameblade pair, they will share the same IP interfaces (IP addresses) for H.248 but musthave different local port numbers. For more information on how to create a virtualmedia gateway, see the SG Virtual media gateway, Ref. [7].

The IP interfaces used for the H.248 signaling are always located on the call handlingblade of the MGW. In case the call handling blade should fail, the IP interfaces forH.248 signaling will be automatically moved to the stand-by blade, which becomesthe new call handler.

There are also other subnets and VLANs used by the MGW blade system that arenot shown in Figure 1, for example, the OAM VLANs and subnets and the VLANsand subnets used for the MGW blade system internal communication.

In Figure 1 above, the two ISERs are normally configured for redundant operation.In the event of an ISER failure, the VRRP protocol will be used to move the next hopIP address (and MAC address) between the two ISER blade systems.

For more details on the subnet and VLAN configuration, see Section 2.2.

Note: Currently maximum one blade pair is supported in a MGW blade system.

Note: The TDM interfaces and the physical Ethernet interfaces (and associatedIP interfaces for media) on the stand-by blade are also used during normaloperation. These interfaces are controlled from the call handling blade.

Note: Figure 1 shows only one next-hop address for H.248 signaling. If SCTPmultihoming is required, see the example configuration described inSection 2.3.2 with multiple H.248 next hops.

2.2 VLAN and subnet configuration detailsTable 1 below describes a suggested subnet and VLAN configuration for the MGW.

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Table 1 Example of subnet and VLAN configuration for the MGW

Note: It is important that the addresses used for H.248 communication andInternal MGW communication (marked with CP addresses in Table 1above) do not use the same address space since they are both used at theMGW Call Processors (CPs). Neither should the H.248 communication orthe Internal MGW communication use the address range of the IS InternalOAM Boot (ISBS), IS Internal OAM Basic (ISOB), IS Internal OAMSupplementary (ISOS), or IS Locally Connected Terminal) ISLCT networksused for IS OAM, since these networks are also used at the CallProcessors. To view the IS networks, go to the Integrated Site ServicesMFA and the Network Configuration service and select IS LogicalNetworks.

2.2.1 Configuration principles for MGW

The following principles have been used for the MGW in Table 1:

Subnetaddress/mask

Subnetsegmentaddress/mask

a) VLAN numberb) VLAN name

ISER addresses:a) Next hop addressb) VRRP addresses

IP Interfaceaddresses

10.0.0.0/8 – a) 1020b) MGW_internal_media

– Based onsubrack, slot,port.SeeSection 2.2.1.

131.0.0.0/24 131.0.0.0/24 a) 1021b) MGW_external_media

a) 131.0.0.1b) 131.0.0.2, 131.0.0.3

131.0.0.4,131.0.0.5,131.0.0.6,131.0.0.7

141.0.1.0/24 141.0.1.0/25and141.0.1.128/25

(CP addresses)

Note: Two sub-net segmentsare used toenable SCTPmultihoming.

a) 1047b) MGW_h248

a) 141.0.1.124b) 141.0.1.125,141.0.1.126anda) 141.0.1.252b) 141.0.1.253,141.0.1.254

Note: The ISERaddresses must beallocated in the end ofthe subnet segmentsto avoid collision withthe MGW addresseson these segments.

141.0.1.1and141.0.1.129

Note: Theseaddresses areautomaticallyassigned bythe MGWfrom the ISsubnet seg-ments whenthe first vir-tual mediagateway iscreated.

10.0.1.0/24 10.0.1.0/24(CP addresses)

a) 1060b) MGW_internal

– 10.0.1.awhere ‘a’ isassignedthroughDHCP.

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• One VLAN and subnet is used for media (payload) sent to and from the corenetwork. You assign the IP addresses on this subnet when you configure the IPinterfaces for media, see Section 3.1.1.

• The MGW uses a separate VLAN and subnet for internal communication withinthe MGW blade system. That is, this VLAN and subnet are used for CallProcessor (CP) communication between the MGW blades. The IP addresses onthis subnet are assigned automatically by the MGW, which uses the DHCPprotocol to request IP addresses from the SIS.

• One VLAN is used for the media transport between the blades of the MGW. Onthis VLAN, private IP addresses are automatically assigned by the MGW bladesystem itself. The IP addresses are based on the subrack and slot position ofeach blade and on the port number for the associated interface. The IPaddresses used are built up as:

10. subrack. slot. port

where

subrack is 0

slot is 1..22

and the physical Ethernet interface number or port number on the blade is 0..1

The address mask on this subnet is 8 bits long.

Example: If the subrack = 0, slot = 3, and port = 0, the address will be 10. 0. 3. 0.

The subnet mask used for the internal media transport is 255.0.0.0.

• One VLAN and an associated subnet is used for the H.248 communication. TheIP addresses used on the H.248 subnet are automatically assigned from the ISsubnet segments for H.248, see Section 2.4.3 and Table 1. IP addresses areassigned from the beginning of the H.248 subnet segment address space andonwards. The IP address assignment is done per MGW blade pair and takesplace when you create the first Virtual media gateway on a specific blade pair.See the service guide Virtual media gateway, Ref. [7].

Separate subnet segments within the H.248 subnet are used to enable SCTPmultihoming according to Section 2.3.2. On the H.248 subnet segments the lastthree addresses in each subnet segment are used by the ISER. It is necessaryto use the last addresses in the subnet segments for the ISER, since the MGWallocates H.248 addresses from the start of each H.248 subnet segment.

• From an IP routing point of view, each media or H.248 subnet segment isconfigured (in the ISER and in any external routers) to be accessible onlythrough the ISER that is used as a gateway for the particular subnet segment.This is to ensure that incoming and outgoing IP packets to and from one specificMGW media or H.248 IP interface are routed through the same ISER.

• On the subnets used for external media, that is, outside the MGW, the firstaddress within each subnet segment (last octet = bbbbb001) is used as next hopaddress at the router. The following two addresses (bbbbb010, bbbbb011) areused as interface addresses on each ISER when two ISERs are configured forredundancy using VRRP (In the event of an ISER failure, the other ISER willtake over the next hop address). The remaining addresses within each subnetsegment (last octet = bbbbb100, bbbbb101, etc.) are used as IP interfaceaddresses on the MGW.

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2.3 Special IP address configuration cases

2.3.1 Multiple virtual media gateways

When multiple Virtual media gateways are created on the same blade pair of theMGW, they will use the same IP interfaces for H.248 signaling, but you must assigndifferent port numbers for the different virtual media gateways. That is, the virtualmedia gateways will use the same IP addresses for H.248 signaling but will usedifferent port numbers.

2.3.2 SCTP multihoming for H.248 signaling

Figure 2 Subnet configuration example for H.248 signaling with SCTP multihoming

Call handling blade

VR

Corenetwork

ISER

IS

VR

= Subnet or subnet-segment addresses

= IP interface (H.248)

= Physical Ethernet interface

= Virtual Router

H.248 addresses:

MGW

Stand-by blade

H.248Subnet/VLAN

= Next hop (H.248)

advertised to IS-external network

MGW = Media Gateway

VR

= SCTP signaling transport

SCTPend point

H.248 subnet: 141.0.1.0/24

H.248 subnet segment 1: 141.0.1.0/25

H.248 subnet segment 2: 141.0.1.128/25

141.0.1.1

141.0.1.129

141.0.1.252

Next hopaddresssegment 1

Next hopaddresssegment 2

R1

R2

SCTPend point

GC

150.0.1.5

150.0.2.5

H.248 route 1: 150.0.1.0/24 via next hop 141.0.1.124

H.248 route 2: 150.0.2.0/24 via next hop 141.0.1.252

H.248 route 2

H.248 route 1

150.0.1.1

Node address:

141.0.1.124

GC = Gateway Controller

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SCTP multihoming is used when redundant H.248 signaling transport is requiredbetween an external Gateway Controller and the MGW. The SCTP multihomingenables quick switchover from one signaling path to another in the event of a networkfailure. The MGW supports establishment of two different paths for the SCTPsignaling per virtual media gateway.

Figure 2 shows an example where a Virtual media gateway using an SCTP type ofH.248 control link has been configured. The SCTP transport from the SCTP endpoint here uses two different IP transport paths for the H.248 signaling. Two differentsubnet segments are used for the two paths. The MGW uses two IP interfaces for thelocal SCTP end point, one at each subnet segment. These interfaces areautomatically created when you create the Virtual media gateway.

When the Virtual media gateway is created, you only have to specify one IPaddress for the remote SCTP end point, the node address of the GC. Any otherremote IP addresses used by the SCTP association will be exchanged by the SCTPprotocol when the H.248 control link is established.

The media gateway will at control link establishment:

• initiate the SCTP transport with the GC towards the GC node address(150.0.1.1).

• send a ServiceChange message to the GC node address (150.0.1.1).

In this example it is assumed that the GC uses the H.248 handoff procedure duringthe ServiceChange. This means that the GC, after it has received a ServiceChangemessage from the media gateway to its node address (150.0.1.1), sends aServiceChange message of type handoff to the MGW, supplying the new GCaddress (150.0.1.5).

After the ServiceChange handoff message has been received from the GC,

• the SCTP communication between the GC node address and the MGW will beshut down

• the MGW will initiate the SCTP communication towards the new GC address(150.0.1.5). Additional addresses for the SCTP end points (for example,150.0.2.5 and 141.0.1.129), both for the MGW and the GC end point, willalso be exchanged during the SCTP initiation procedure.

• the MGW will send a second ServiceChange message to the new GC address(150.0.1.5).

See also Ref. [11] and Ref. [12] for more information on how the H.248 SCTP controllink communication is established.

For the SCTP multihoming case you also need to configure two differentH.248 routes. One H.248 route for each next hop address indicated in Figure 2. TheRemote subnet address and Remote subnet mask length of the H.248 routemust be specified to identify the associated subnet used in the remote GatewayController for this particular SCTP path. One of the H.248 routes must be configuredto contain the node address of the remote GC, since this address is always used asGC contact address at H.248 control link establishment, for example at MGW restart.Alternatively, you may specify a separate H.248 route for the GC node address.

Note: To achieve the wanted behavior for the SCTP multihoming, it is necessarythat the two different SCTP paths use different routers all the way throughthe core network.

Note: The MGW also supports GCs that do not use the ServiceChange handoffprocedure described above. In this case only the GC node address will beused as destination address at initiation of the SCTP transport and at theServiceChange procedure.

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2.4 IS configurationSection 2.4.1 through Section 2.4.4 present details on the IS parameterconfiguration needed for the MGW operation. The items described more in detailhere are:

• VLAN configuration, Section 2.4.2

• traffic class configuration, Section 2.4.4

• change of IS configuration, Section 2.4.1.

When you configure the IS parameters described below you have to follow a set ofpredefined configuration sequences. That is, when you have created one ISmanaged object in the ISM, you will be guided automatically to another data entryform where an associated IS managed object can be created.

These are examples of IS managed object configuration sequences:

• Create IS VLAN –> Create BS VLAN –> Create BS VLAN SAP

• Create IS IP Traffic class –> Create BS IP Traffic class

• Create IS logical network –> Create IS subnet –> Create IS subnet segment–> Create BS logical network –> Create BS subnet –> Create BS subnetsegment

You can interrupt any of these sequences and go directly to the input form of yourchoice. Especially in cases where some of the configurations objects are predefinedfor the blade system (for example, the objects associated with the H.248 signaling orwith the traffic classes) you do not need to create them. These objects are createdautomatically when you create the associated blade system. In this case, you onlycreate the IS objects you need, and afterwards you open the IS configuration data forthe blade system in the Integrated Site Services MFA where you go to the NetworkConfiguration service and select Blade Systems. Here you select the appropriateblade system, open the blade system configuration object of your choice, and from adrop-down list or input field, you select the mapping to the appropriate IS object.Predefined objects are indicated by ** in the tables of Section 2.4.2 to Section 2.4.4.The IS object to which the predefined blade system object must be mapped is alsoindicated in the tables of Section 2.4.2 through Section 2.4.4.

The input menu to select for access to each configuration object is indicated below.For the selected menu, the data to enter on the input form is given by the tables ofSection 2.4.2 through Section 2.4.4 and in Table 1.

For more information on the different IS configuration objects see, Ref. [3].

2.4.1 Change of IS configuration

Caution

Do not change the IS configuration unless you are conscious of the consequencesof your changes.

The blade system configuration is based on the IS configuration, so changes to theIS configuration may have significant or disastrous impact on the blade system.

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If, after configuring the MGW, you change the IS configuration data, the MGW will notupdate its configuration automatically. That is, if the MGW blade system is using aparticular IS VLAN, IS logical network, IS subnet, IS subnet segment, IS traffic class,etc., this entity must not be changed in IS.

The IS VLAN and IS network objects that must not be changed are:

• the VLANs, subnets and subnet segments used for H.248 communication, seeSection 2.4.3

• the VLANs, subnets and subnet segments used for blade system internalcommunication, see Section 2.4.3.

In the event that such a change has to be made, the MGW needs to be reconfiguredor reinstalled. That is, you have to remove all concerned configuration in the MGW,change the IS parameter configuration, and then reconfigure the MGW.

2.4.2 Required VLAN configuration in IS

You must configure the MGW specific VLANs to be used in IS. It is recommendedthat you do this before installing the MGW blade system. In the Integrated SiteServices MFA, select the Network Configuration service, and the submenu ISVLANs. Here you must create the MGW-specific VLANs as described in Section 2.2Table 1 and below in Table 2:

• internal VLAN for the MGW

• H.248 (signaling) VLAN for the MGW (and GC)

• internal media (payload) VLAN for the MGW

• external media (payload) VLAN for the MGW

Table 2 IS VLAN example for the MGW

Note: When the gateway controller is located in the same IS site as the MGW thesame H.248 VLAN can be used for both the MGW and the GC.

2.4.2.1 Blade-system specific VLAN configuration

You must here configure the blade system VLANs and tie them to associatedIS-VLANs that the MGW uses. This is to enable VLAN transport through the MXB L2switch.

In the Integrated Site Services MFA, go to the Network Configuration service andselect Blade Systems. Select the blade system and create the desired blade systemVLANs to use for this particular blade system. Also map each blade system VLAN toan already configured IS VLAN, see Table 3.

Some of the VLANs are used by many blade systems, that is, the are not private tothe configured blade system. In this case the blade system VLAN must have thePrivate VLAN attribute set to false.

IS VLAN name IS VLAN ID

MGW_internal 1060

h248 1047

MGW_external_media 1021

MGW_internal_media 1020

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Note: The blade system VLANs are partially preconfigured (indicated by ** inTable 3). Here you only have to do the mapping to the corresponding ISVLAN. These objects have to be fully configured before the blade systemmay be unlocked and brought into operation.

Table 3 Blade system VLANs for MGW

From the same submenu you must also create a blade system VLAN Service AccessPoint (SAP) for each blade where the VLAN is to be accessible. Here you map theblade system VLAN SAP to the already configured blade system VLANs accordingto Table 4.

For the MGW blade system, all VLANs must be configured to be accessible from allblades in the blade system. The number of SAPs required to be configured isdependent on the number of blades in the MGW blade system.

The VLANs for media must be configured to be accessible from both interfaces to thebackplane (link 0 and link 1 in Table 4), whereas the VLANs for internalcommunication and H.248 only should be accessible from the first interface (link 0).

Some of the VLANs should be protected, that is, should never be removed from MXBL2 transport even if a LAN fault is detected for a blade. That is, if Protected VLAN istrue the VLAN will remain connected in the MXB even if the LAN fault supervisionhas detected a fault on the particular blade. On the other hand if Protected VLAN isfalse, a blade deemed as faulty will be removed from the VLAN.

Table 4 Blade system VLAN service access points for MGW

BS VLAN name IS VLAN namePrivateVLAN

Internal_vid ** MGW_internal true

GW-H.248_vlan ** h248 false

MGW_external_media ** MGW_external_media false

MGW_internal_media ** MGW_internal_media true

Configured atblade/link

BS VLAN service accesspoints

BS VLAN nameProtectedVLAN

StaticVLAN(notusingGVRP)

MGW at blade 1/link 0 Internal_sap1 Internal_vid true yes

MGW at blade 2/link 0 Internal_sap2(2 blades assumed here)

Internal_vid true yes

MGW at blade 1/link 0 GW-H.248_sap1 GW-H.248_vlan true yes

MGW at blade 2/link 0 GW-H.248_sap2(2 blades assumed here)

GW-H.248_vlan true yes

MGW at blade 1/link 0 MGW_ext_media_sap_1_0 MGW_external_media false yes

MGW at blade 2/link 0 MGW_ext_media_sap_2_0(2 blades assumed here)

MGW_external_media false yes

MGW at blade 1/link 1 MGW_ext_media_sap_1_1 MGW_external_media false yes

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2.4.3 Required network configuration in IS

When you have configured the VLANs as described in Section 2.4.2, you mustconfigure the IS logical networks, IS subnets, and IS subnet segments that needconfiguration support (for example, support for address allocation via DHCP) from IS.Go to the Integrated Site Services MFA and the Network Configuration service,and select IS Logical Networks. On the IS Logical Networks page you must createthe MGW-specific IS Logical networks, IS Subnets, and IS Subnet segments asdescribed in Table 5 below.

You configure the IS objects and relations described in Table 5.

For each object you must specify the required information, for example addressranges, according to Table 1 and Section 2.2.

Note: Neither the MGW_internal_media network nor the MGW_external_medianetworks needs to be defined here, since these networks need no specificIS subnet support.

Note: If the Gateway Controller is located in the same IS site as the MGW, theH.248 signalling still has to be sent via the router, as different subnetsegments are used for the GC and the MGW.

Note: Two IS subnet segments for H.248 are required. This is to enable SCTPmultihoming.

Table 5 IS network configuration objects

MGW at blade 2/link 1 MGW_ext_media_sap_2_1(2 blades assumed here)

MGW_external_media false yes

MGW at blade 1/link 0 MGW_int_media_sap_1_0 MGW_internal_media true yes

MGW at blade 2/link 0 MGW_int_media_sap_2_0(2 blades assumed here)

MGW_internal_media true yes

MGW at blade 1/link 1 MGW_int_media_sap_1_1 MGW_internal_media true yes

MGW at blade 2/link 1 MGW_int_media_sap_2_1(2 blades assumed here)

MGW_internal_media true yes

IS logical network name IS subnet name1) IS subnet segment name2) DHCP enabled3) Router address

IS VLAN name

MGW_internal_ln MGW_internal_sn 1) MGW_internal_sns2) True3) No router address

MGW_internalsee Table 3.

MGW_h248_ln MGW_h248_sn 1) MGW_h248_sns12) False3) Yes, see Table1)

h248see Table 3.

Configured atblade/link

BS VLAN service accesspoints


StaticVLAN(notusingGVRP)

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2.4.3.1 Blade-system specific network configuration

For each blade system, you need to configure which of the IS network configurationobjects it uses. This configuration is done in the Integrated Site Services MFA usingthe Network Configuration service and the submenu Blade Systems.

You open the created blade systems and create the blade system logical networks(LN), blade system subnets, and blade system subnet segments for each bladesystem and map them to the corresponding IS network configuration objectsaccording to Table 5. All these actions are performed from the BS Logical Networkssubmenu. All logical networks must be defined as non-private (Private = false),since they are used by multiple blade systems.

Note: Some of the blade system network objects are partially preconfigured(indicated by ** in Table 6). For these objects you only have to do themapping to the corresponding IS network object. Note that these objectshave to be fully configured before the blade system may be unlocked andbrought into operation.

Note: It is essential that you do not decrease the number of IP addresses on theInternal subnet segment (Internal_sns) below when you configure thisblade system subnet segment, since this is the minimum requirement for aMGW blade system with two blades.

Table 6 Blade system network configuration objects for MGW

2.4.4 Required traffic class configuration in IS

You must configure the IS IP traffic classes to use for media (payload), H.248signaling and blade-system internal communication.

MGW_h248_ln MGW_h248_sn 1) MGW_h248_sns22) False3) Yes, see Table1

h248see Table 3.

BS LN name / IS LN nameBS subnet name /IS subnet name

1) BS subnet-segment name2) IS subnet-segment name3) Number of IP addresses4) Router required

Internal ** / MGW_internal_ln Internal_sn ** /MGW_internal_sn

1) Internal_sns **2) MGW_internal_sns3) 10 IP addresses4) No

GW-H.248_ln **/MGW_h248_ln GW-H.248_sn **/ MGW_h248_sn 1) GW-H.248_sns1 **2) MGW_h248_sns13) 1 IP address4) Yes

GW-H.248_ln **/MGW_h248_ln GW-H.248_sn **/ MGW_h248_sn 1) GW-H.248_sns2 **2) MGW_h248_sns23) 1 IP address4) Yes

IS logical network name IS subnet name1) IS subnet segment name2) DHCP enabled3) Router address

IS VLAN name

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In the Integrated Site Services MFAG, go to the Network Configuration serviceand select IS IP Traffic Class. For each IP traffic class you specify the DifferentiatedServices Code Point (DSCP) to use for IP packets using this traffic class. You alsoselect the IS LAN traffic class to be used for the particular IS IP traffic class.

Note: The IS LAN traffic classes are predefined and cannot be changed.

Note: Multiple IS IP traffic classes use the same IS LAN traffic class.

Note: Outgoing media IP packets from the MGW will use the DSCP specified forthe MGW_audio_iptc, MGW_video_iptc or MGW_data_iptc traffic classesin Table 8. The DSCP can later be changed by the ISER, if DSCPremapping has been configured for the ISER (see Section 2.5.3).

Note: The P-bits in Table 7 below do only indicate which queue that will be usedin IS LAN switch (MXB) for the specific traffic class. But a higher P-bit valuedoes not necessarily indicate a higher priority in the scheduling forrespective queue.

A proposed configuration for IS LAN traffic classes and IS IP traffic classes isdescribed in Table 7 and Table 8.

Table 7 IS LAN traffic classes

Table 8 IS IP traffic classes

2.4.4.1 Blade-system specific traffic class configuration

For the MGW you must configure which IS traffic classes and IS LAN traffic classesto be used. That is, you create the mapping:

• from each blade system LAN traffic class to the corresponding IS LAN trafficclass (see Table 9)

• from the blade system IP traffic classes to the IS IP traffic classes (seeTable 10).

IS LAN TC name P-bits Comment

IS_LAN_TC_F 5 Used for real time (audio) media transport

IS_LAN_TC_D 3 Used for video media transport

IS_LAN_TC_C 2 Used for data media transport

IS_LAN_TC_B 1 Used for H.248 communication and for MGW bladesystem internal communication.

IS IP TC nameDSCP/(decimal value)

IS LAN TC name Comment

MGW_audio_iptc EF/ (46) IS_LAN_TC_F Used for media type audio

MGW_video_iptc AF11/ (10) IS_LAN_TC_D Used for media type video

MGW_data_iptc AF21/ (18) IS_LAN_TC_C Used for media type data

MGW_h248_iptc AF31/ (26) IS_LAN_TC_B Used for H.248 communication.

MGW_int_iptc DF/ (0) IS_LAN_TC_B Used for MGW internal communication.

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This configuration is done in the Integrated Site Services MFA using the NetworkConfiguration service and the Blade Systems submenu. You open the createdblade systems and create the appropriate blade system IP traffic classes.

Note: Since most of the blade system LAN and IP traffic class names are partiallypreconfigured (indicated by ** in the tables) you do not need to createthem. You only need to map them to the corresponding IS entity. Note thatthe objects have to be fully configured before the blade system may beunlocked and brought into operation.

Table 9 Blade system LAN traffic classes for MGW

Table 10 Blade system IP traffic classes for the MGW

2.5 Configuration of ISERFor details on the ISER configuration, see the MFAG ISER, Ref. [5].

2.5.1 Network configuration for ISER in IS

In a similar way as for the MGW blade system, you have to configure IS with theappropriate objects needed for the ISER operation. That is, you have to configure:

• Accessibility to the external media and signaling (H.248) VLANs for the ISER:

You must create BS VLANs and BS VLAN SAPs for the ISER that will beassociated with the media and H.248 signaling IS VLANs, since these ISVLANs are connected to the ISER to enable forwarding of data to and from theMGW to and from the IS external networks. See Table 11 and Table 12.

• Forwarding of management operations to a Network Management Center(northbound interface), if required.

You must configure the required VLAN, logical network, subnet, and subnetsegment for the northbound interface. Note that in this case you will have toupdate the preconfigured isnb logical network with its associated subnet andsubnet segment to fit to the required IP address plan. You do this in IntegratedSite Services MFA using the Network Configuration service and the submenuIS Logical Networks. Choose the isnb network and open the associated ISSubnet. Here you can define a new subnet address for this subnet by changingthe predefined default address.

BS LAN TC name IS LAN TC name Comment

GW-H.248_lantc ** IS_LAN_TC_B Used for H.248 communication.

Internal_lantc ** IS_LAN_TC_B Used for blade system internal com-munication.

BS IP TC name IS IP TC name Comment

GW-H.248_iptc ** MGW_h248_iptc Used for H.248 communication.

Internal_iptc ** MGW_int_iptc Used for blade system internal communication.

MGW_audio_iptc ** MGW_audio_iptc Used for media of type audio

MGW_video_iptc ** MGW_video_iptc Used for media of type video’

MGW_data_iptc ** MGW_data_iptc Used for media of type data.

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Table 11 Blade system VLANs for ISER

Table 12 Blade system VLAN Service Access Points for ISER

2.5.2 ISER network and address configuration

Additionally, you must configure the ISER itself with the VLANs to use for signalingand media and associate them with each virtual router as shown in Figure 1 andTable 1. As suggested in Figure 1, you can configure one virtual router for H.248signaling and another for media transport.

For each next hop address that has been specified for the media and H.248 signalingsubnet segments (see Figure 1, Table 1), you must configure an interface in the ISERfor the appropriate VLAN.

In addition, you need to configure the IP packet forwarding in the virtual routers touse either static routing or a dynamic routing protocol.

You can also configure the ISERs for redundant operation (using VRRP) by addingan extra stand-by ISER blade system to each ISER. In this case you need toconfigure several interfaces per ISER and VLAN, since an extra, unique, IP addressis required per ISER in addition to the next hop (router) address.

You must also configure VLANs, interfaces, and an associated virtual router for thenorthbound management interface, if required. Also for the northbound interface youmust configure an interface (next hop) in the ISER.

Note: Adding a stand-by ISER blade system does not affect the MGWconfiguration itself, since the same next hop (router) addresses will beused towards the ISERs in a pair. (The next hop address will be movedbetween the ISERs in the event of a failure.)

Note: From the ISER point of view the IS subnet segments are seen as ordinarysubnets. That is, if subnet segments are to be configured for IP routing youconfigure them as subnets in the ISER.

2.5.3 DSCP configuration

If the networks outside of IS and the IS-internal network belong to different DiffServdomains, you have to configure the ISER to remap the DiffServ code points (DSCP)between these domains.

BS VLAN name IS VLAN namePrivateVLAN

MGW_external_media MGW_external_media false

MGW_h248 MGW_h248 false

NorthBound_mgmt IS NorthBound VLAN false

Configuredat blade/link

BS VLANservice access points


StaticVLAN(not usingGVRP)

ISER at link 0 MGW_external_media_sap MGW_external_media false yes

ISER at link 0 MGW_h248_sap MGW_h248 false yes

ISER at link 0 NorthBound_mgmt_sap NorthBound_mgmt false yes

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The MGW always inserts the DSCP for outgoing media and H.248 signaling packetswhen the associated IP packets are sent. For media the DSCP is based on the mediatype (voice, video, or data) in accordance with the definition of the IS IP traffic classesfor media specified in Table 8. The DSCP used for H.248 signaling is defined by thecorresponding IP traffic class used for H.248 accordance with Table 8.

You have to configure the ISER to use the correct IS IP traffic class (DSCP) and ISLAN traffic class (p-bits) on the IS VLANs in according to Table 7 and Table 8 for IPpackets forwarded from the IS external network into IS. That is, the ISER should herebe configured to forward incoming IP packets with a certain DSCP using the correctIS IP traffic class and IS LAN traffic class. See Ref. [10] for more information.

2.5.4 Secure H.248 signaling

If there are requirements on security for the H.248 signaling when the GatewayController (GC) is located outside of IS, you have to configure the virtual router(s)used for H.248 signaling in the ISER with for example IPsec. In this case a IPsectunnel has to be established from the ISER to the remote GC site. Please consultRef. [6] for information on how to configure the ISER with IPsec.

2.5.5 ISER firewall configuration

You are recommended to configure the virtual routers in the ISER with a number ofIP firewall filters to enhance the security of the IS and the MGW. Section 2.5.5.1 givesan overview of the needed security configuration for the MGW.

2.5.5.1 Security configuration for the MGW

You are recommended to configure the following filters for both media and signalingin the virtual routers:

• Discard IP packets with IP options field.

• Discard fragmented IP packets (Note however that for a H.248 signaling, whenSCTP is used and if the MTU for SCTP is set to a greater value than 1500 octets,IP fragmentation needs to be supported since IP packet size may exceed themaximum MTU (1500 octets) for Ethernet).

• Discard TCP packets, since TCP is not used in the MGW.

• Discard IP packets from an illegal IP source address (or source subnets).

• Discard Internet Control Message Protocol (ICMP) packets.

• Forward only IP packets with protocol 17 (UDP) and 132 (SCTP).

• For media, forward only IP packets with destination port numbers in the rangefrom 1026 to 65535.

• For H.248 signaling, forward only IP packets with destination port numbers inthe range from 1024 to 65535.

Note: By not allowing ICMP packets you disable the use of ping commands fromthe network outside of IS towards the MGW.

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3 The Network Configuration serviceThe Network Configuration service provides management operations forconfiguration of objects needed for media and H.248 communication with theexternal core network. The objects that may be configured in this service are:

• IP interfaces, see Section 3.1

• Next hops, see Section 3.2

• Static Routes, see Section 3.3

• Virtual router, see Section 3.4

• Address Resolution Protocol (ARP) parameters, see Section 3.5

• Media supervision, see Section 3.6

• H.248 routes, see Section 3.7

• SCTP parameters, see Section 3.8

Note: The local and remote IP addresses for H.248 communication are notconfigured via the Network Configuration service. You specify themwhen you create a virtual media gateway. See SG Virtual media gateway.

3.1 IP interface configurationFor external media communication you must configure IP interfaces to forward andreceive the media to and from the IS external network. These IP interfaces are usedby the MGW as source and destination for media traffic. You need to define one IPinterface for external media transport per physical Ethernet interface. That is,altogether four IP interfaces, since there are 2 physical Ethernet interfaces per bladeand two MGW blades. The IP interfaces for external media will use the externalmedia VLAN as defined in Table 3.

Normally all the MGW IP interfaces for media will be located in the same subnet andsubnet segment. However, for large MGWs it is possible to place the IP interfaces ofdifferent blades in different subnet segments. This is needed, for example, in the casewhen it is desired to direct the media traffic from one MGW blade to a specific router(ISER), since the traffic to and from a specific IP interface will go via the next hopaddress in the same subnet segment.

When the GC requests an IP address and port for media transport, the MGW selectsone of the configured IP interfaces. Normally an IP interface is selected at the sameblade as where the TDM (STM-1) resource for a particular call is located.

Note: You don’t have to configure IP interface objects for the H.248communication. The IP interfaces (IP addresses) for the H.248 signalingwill instead be created automatically when you configure the virtual mediagateway, see SG Virtual media gateway.

3.1.1 Creating IP interfaces

To create an IP interface, in the Media gateway MFA select Network configuration.On the Create menu, click IP interface. Enter the attributes according to the listbelow, and click Create.

The following attributes must be specified for the IP interface:

• IP interface address, see Section 4.1.1.2

• Subrack, see Section 4.1.1.8

• Slot, see Section 4.1.1.5

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• Port, see Section 4.1.1.4

• Subnet mask length, see Section 4.1.1.6

• Subnet segment mask length, see Section 4.1.1.7.

3.1.2 Listing IP interfaces

To display IP interface information, in the Media gateway MFA, select Networkconfiguration. On the Open menu, click Virtual Router, and select an IP interface.

In addition to the attributes specified at creation of the IP interface the followingattributes are presented:

• Administrative state, see Section 4.1.1.1

• Operational state, see Section 4.1.1.3

• VLAN ID, see Section 4.1.1.9.

3.1.2.1 IP interface statistics

The following statistics are displayed for the IP interface:

• Transmitted packets, see Section 4.1.2.10

• Transmitted octets, see Section 4.1.2.9

• Received packets, see Section 4.1.2.8

• Received octets, see Section 4.1.2.7

• Malicious packets, see Section 4.1.2.6

• Excessive packets, see Section 4.1.2.4

• Excessive octets, see Section 4.1.2.3

• Filtered packets, see Section 4.1.2.5

• Discarded, other reason, see Section 4.1.2.2

• Discarded, no next hop, see Section 4.1.2.1.

3.1.3 Locking or unlocking an IP interface

If you want to take an IP interface out of service, that is, prevent connections frombeing set up over the interface, you can lock the interface immediately or gracefully.

To change the Administrative state of an IP interface, you select Networkconfiguration in the Media gateway MFA. On the Open menu, click Virtual Router,and select the IP interface of interest and click either the Graceful lock or the Lockbutton:

• Lock – Sets the Administrative state of the IP interface to either of shuttingdown (if there are connections) or locked (if there are no connections). Newconnections will not be allowed. When locking the interface in this way, allconnections on the interface will be released. As long as there are remainingconnections on the interface, the Administrative state will remain in theshutting down state. When all connections have been released, theAdministrative state changes to locked.

When the connections are released, the Gateway Controller (GC) will beinformed via notifications about the concerned connections over H.248.

You can initiate the lock action when the Administrative state is eitherunlocked or shutting down.

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• Graceful lock – Sets the Administrative state of the IP interface to either ofshutting down (if there are connections) or locked (if there are noconnections). New connections on the interface will not be allowed, but existingconnections remain until they are released. When all connections have beenreleased, the Administrative state will change to locked.

You can initiate the graceful lock action when the Administrative state isunlocked.

An IP interface can be unlocked again by clicking the Unlock button when theAdministrative state is shutting down or locked.

Note: Locking an IP interface will not remove the IP interface from the mediaVLAN. The address remains and is accessible. External IP hosts can stillsend IP packets to the IP interface.

3.1.4 Deleting IP interfaces

In the Media gateway MFA select Network configuration. On the Open menu, clickVirtual Router, and select the IP interface of interest. Delete the interface by clickingthe Delete button at the bottom of the page.

Note: An IP interface can be deleted only if it is locked. See Section 3.1.3.

3.2 Next hop configurationYou must also configure one or several Next hops for the media transport. EachNext hop defines a next hop IP address for media. The next hop is the address ofthe router via which external media (payload) will be sent and received. In theexample in Figure 1 in Section 2.1, the next hops are the IP addresses used in themedia subnets at the ISER. Consequently the next hop addresses must beconfigured as IP interfaces in the router (ISER) as well.

You must configure the Next hops to be located in the same subnet segment as theassociated IP interfaces that will use them. Whether you create the IP interface orthe Next hop first is not important.

Note: A Route and a Next hop are only needed when the destination network(subnet) for media is another than the one that the MGW media IPinterfaces are located in.

Note: You do not have to configure any Next hop objects in the MGW for theH.248 communication. For H.248 you have to configure a H.248 route andthe associated next hop IP interface (IP address) in the router (ISER), seeSection 3.7.1.

3.2.1 Creating Next hop addresses

To create a next hop address you go to the Media Gateway MFA and the NetworkConfiguration service and select Create next hop.

There is only one attribute associated with the next hop:

• Next hop: The IP address of the gateway used to transport the payload (media)to (and from) the external network.

3.2.2 Locking or unlocking a next hop

If you want to take a next hop out of service, that is, prevent connections from beingset up over the next hop, you can lock the next hop immediately or gracefully.

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To change the Administrative state of a Next hop, select Network configurationin the Media gateway MFA. On the Open menu, click Virtual Router and select thenext hop of interest.

You can click either of the buttons Graceful lock or Lock:

• Lock – Sets the Administrative state of the next hop to either shuttingdown or locked. When the next hop is locked, all existing connections thatuse the next hop will be released. As long as there are remaining connectionsat the next hop, the Administrative state will remain in the shutting downstate. When all connections have been released the Administrative state willchange to locked.

When the connections are released, the Gateway Controller (GC) will beinformed via notifications about the concerned connections over H.248.

You may initiate the lock action when the Administrative state is eitherunlocked or shutting down.

• Graceful lock – Sets the Administrative state of the next hop to either ofshutting down or locked. New connections at the next hop will not beallowed but existing connections remain until the are released. When allconnections have been released, the Administrative state will change tolocked.

You can initiate the graceful lock action when the Administrative state isunlocked.

You can unlock a next hop by clicking the Unlock button when the Administrativestate is shutting down or locked.

3.2.3 Listing and deleting next hops

To view the created next hops, go to the Media gateway MFA and the Networkconfiguration service. On the Open menu click Virtual Router and select the nexthop of interest.

You delete a next hop by marking its check box and then clicking the Delete button.

Note: A next hop can only be deleted if it is locked and if it not used by any route.See Section 3.2.2 and Section 3.3.3.

3.3 Static route configurationIf you have configured Next hops for media transport you also have to define aStatic Route and associate the appropriate next hops (one or several) with the route.The Static Route contains information on the next hop address(es) that are used toreach a certain destination network (IP subnet) outside of IS, that is, a network(subnet) where another MGW is located.

Multiple routes can be configured in configurations where different core networksubnets are reached through different routers (normally ISERs) or when there aremultiple destination networks (external MGWs located in different subnets) that mustbe reached from the MGW. In the simplest case only one default route for media isneeded, see Section 3.3.1.

If IP interfaces in different subnet segments in IS should be able to access the samedestination network, multiple next hops can be defined for the same route. Then theroute must have a next hop address in each subnet segment.

Note: A Static Route and a Next hop are only needed when the destinationnetwork (subnet) for media is different from the one that the MGW mediaIP interfaces are located in.

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Note: You do not have to define a Static Route object for H.248 communication.In this case you configure a H.248 route. See Section 3.7.

Note: When you create IP interfaces a route of interface route type will becreated automatically.

3.3.1 Creating static routes

To create a static route, you go to the Media Gateway MFA and select NetworkConfiguration. On the Create menu click Static Route. Type the subnet addressand mask length of the destination network and select the next hop address to reachthe destination network. Then click Create.

If you want to create a default route for media you set the Remote subnet addressto 0.0.0.0 and the Remote subnet mask length to 0.

The following attributes must be specified for the route:

• Remote subnet address, see Section 4.3.1.2

• Remote subnet mask length, see Section 4.3.1.3

• Next hop address, see Section 4.3.1.1.

3.3.2 Listing routes

To display route information, in the Media gateway MFA select Networkconfiguration. On the Open menu click Virtual Router, and select a route.

The list contains both the Static routes that have been created manually and theinterface routes that have bee created by the system when you create IP interfaces.

Note: H.248 routes are not listed here under the Virtual Router menu but underthe Open H248 route menu. See Section 3.7.2.

3.3.3 Add or remove next hop to and from route

When you select a route (that is, click its table row icon on the Virtual router menu)you can add one or more Next hops to the existing route. Additional next hops areneeded if there are IP interfaces in different subnet segments that must use the sameroute. The route must then have a next hop address in each subnet segment.

You can also remove a next hop from the route. Open the route for viewing by clickingits table row icon on the Virtual router menu. You delete a next hop from the routeby marking the delete box of the particular next hop and then clicking the Deletebutton at the bottom of the page.

Note: Removal of a next hop from the route will not delete the Next hop objectitself. How to delete a Next hop is described in Section 3.2.3.

Note: Next hops cannot be added to a Route of type interface route.

Note: Removal of a Next hop from a route will only affect new call setups thatuses the particular route. Already established calls will still use the next hopaddress until the calls are released.

3.3.4 Deleting routes

After selecting the Route from the Virtual router menu, you can delete it by clickingthe Delete button.

Note: Deletion of a Route will not delete the Next hop(s) that the route uses.How to delete a Next hop is described in Section 3.2.3.

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Note: Routes of the interface routes type cannot be deleted. They are deletedwhen the corresponding IP interfaces are deleted.

Note: Deletion of a Route only affects the setup new calls that use the particularroute. Already established calls continues using the next hop address(es)of the route until the calls are released.

3.4 Virtual routerThe virtual router in the MGW represents the core IP network to which the MGW isconnected. There exist only one Virtual router in the MGW, and this object is createdautomatically.

The virtual router menu presents an overview in table format of the configured IPinterfaces, Next hops, and Routes used for media transport.

See also:

• IP interface configuration, Section 3.1

• Next hop configuration, Section 3.2

• Static Route configuration, Section 3.3.

From the virtual router menu you can also delete or modify the objects listed above.

Note: Interface routes cannot be deleted in the route table. The interface routesare deleted automatically when you delete the corresponding IP interface.

Note: The H.248 routes are not listed on the Virtual router menu. Only objectsassociated with media transport are listed here.

3.5 ARP parametersThe MGW blade system uses the Address Resolution Protocol (ARP) to detectcertain network problems for media (payload) communication:

• failure to contact the Next hop address

• IP address collision.

All Next hop addresses for media are supervised with ARP to make sure that theaddresses are reachable from the MGW IP interfaces. Also, when you create a newIP interface for media, the IP address of the interface will be checked via ARP toverify that it does not conflict with other already created IP interface addresses.

The corresponding alarms are next hop Alarm and address Collision Alarm, seeRef. [9]. There are a number of parameters that control how the ARP monitoringworks.

To display and update ARP monitoring parameters, you go to the Media gatewayMFA and select Network configuration. On the Open menu, click ARPparameters.

The following parameters are displayed, and can be updated:

• Event filter, see Section 4.5.1.2

• Poll time up, see Section 4.5.1.5

• Poll time down, see Section 4.5.1.4

• Poll time collision, see Section 4.5.1.3

• Address collision filter, see Section 4.5.1.1.

To save your changes, click Apply.

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3.6 Media supervisionThe media supervision is a function used to detect media streams (connections) thatare inactive.That is, no IP packets have been received for a specified period of time(Hanging media supervision time) on a particular media stream.

The media supervision is used when the end users might have released the calls butthe GC and the MGW have not been informed due to errors in the network etc. Whenthe media supervision is used for a TDM-to-IP call, only the media flow in onedirection, from the IP network to the TDM side, will be supervised.

The GC orders (via H.248) the MGW to supervise media per termination or mediastream. For a description of the concepts of terminations and streams, see Ref. [12].

When the MGW detects a hanging media stream, it notifies the Gateway Controllervia H.248, and the Gateway Controller releases the streams of the associated call.

You may specify the following parameter for the media supervision:

• Hanging media supervision time, see Section 4.6.1.1.

3.7 H.248 route configurationThe MGW uses an H.248 route to know via which next hop it should send its H.248signalling to a Gateway Controller (GC). For each H.248 IS subnet segment thatneeds to be routed, one or several H.248 routes must be created.

The Local subnet segment attribute in the H.248 route points at an IS subnetsegment that contains information about which next hop (router) IP address will beused to reach a certain destination network (IP subnet), that is, a network where oneor more Gateway Controllers (GCs) is located.

When SCTP multihoming is used, multiple H.248 routes are needed. Note that youmust also configure one of the H.248 routes to contain the node address of theremote GC. You can also create a separate H.248 route for this purpose.

There are also other cases when you need to configure multiple H.248 routes. Forexample, when different virtual media gateways are controlled by different remoteGCs that have their H.248 IP interfaces located in different subnets that cannot becombined into one route.

Note: It is recommended not to create more than a few (less than five) H.248routes, since the performance of the H.248 signaling may decrease.

Note: It is important that the remote subnet addresses used for the H.248 routesdo not conflict with the addresses used for internal MGW communication(see Section 2.2), since both are used by the MGW Call Processors (CPs).Neither should the remote subnet addresses in the H.248 routes use theaddress range of the ISBS, ISOB, ISOS, or ISLCT networks used for ISOAM, since these networks are also used by the Call Processors. To viewthe IS networks, go to the Integrated Site Services MFA and the NetworkConfiguration service, where you select IS Logical Networks.

Note: It is not allowed to create default routes for H.248. That is, it is not permittedto create a H.248 route with Remote subnet address 0.0.0.0.

3.7.1 Creating H.248 routes

To create a H.248 route, go to the Media gateway MFA and select Networkconfiguration. On the Create menu, click H.248 route. Enter the attributesaccording to the list below and click Create.

You must specify the following attributes for the route:

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• Remote subnet address, see Section 4.7.1.2

• Remote subnet mask length, see Section 4.7.1.3

• Local subnet segment, see Section 4.7.1.1.

Note: The Local subnet segment also identifies the next hop (router) addressto use for the H.248 route.

3.7.2 Listing H.248 routes

To display route information, select Network configuration in the Media gatewayMFA. On the Open menu, click H.248 Route, and select a route.

3.7.3 Deleting H.248 routes

After selecting a route in the H.248 Route menu, you can delete it by clicking theDelete button.

3.8 SCTP parametersThe SCTP parameters that are common to all H.248 Control links using SCTP canbe changed on the SCTP Parameters page. The default values of these parametersare the values specified by Ref. [11].

Changes made to these parameters will only take effect when an SCTP Control linkis established. That is, if you change these parameters, and there is already an activeSCTP control link present, you have to lock and unlock this H.248 Control link toenforce an update of the parameters. See SG Virtual media gateway for moreinformation on how to lock and unlock a control link.

Caution

Do not change the SCTP parameters unless you are conscious of the consequencesof your changes.

Note: There are also SCTP counters that are presented per H.248 control link.See SG Virtual media gateway for more information on these counters.

3.8.1 Smoothed round-trip time and time variation calculation

The round-trip timeout (RTO) used for SCTP transport is updated continuouslyaccording to the method described below. This is, for example, to enable the SCTPprotocol function to know when to resend a message in the event of noacknowledgement from the remote end.

According to the SCTP RFC, Ref. [11], the message round-trip timeout is calculatedfrom the smoothed round-trip time and the time variation. This value is used tocalculate the round-trip timeout (RTO) as:

RTO = SRTT + 4 * RTTV

where the smoothed round-trip time SRTT is calculated as:

SRTT = (1 – RTO.Alpha) * SRTT + RTO.Alpha * R’

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where:

• SRTT is the smoothed round-trip time, initially set to the configured Initial RTOvalue

• R’ is the measured round-trip time for this message

• RTO.Alpha is the smoothing factor according to Table 13 below,

and the round-trip time variation RTTV is calculated as:

RTTV = (1 – RTO.Beta) * RTTV + RTO.Beta * | SRTT – R’ |

where:

• RTTV is the smoothed round-trip time variation, initially set to 0

• SRTT is the smoothed round-trip time above

• R’ is the measured round-trip time for this message

• RTO.Beta is the smoothing factor according to Table 13 below.

When the RTO timer expires, the message is resent using 2 * RTO as the new timervalue.

Note: The round-trip timeout (RTO) mentioned in this section may vary betweenthe limits specified by the Minimum RTO and Maximum RTO described inSection 3.8.2. From start the RTO will be set to the Initial RTO. At SCTPmultihoming, separate RTO values will be calculated for each pair of localand remote IP address combinations.

Table 13

3.8.2 Changing SCTP parameters

To display the SCTP parameters, go to the Media gateway MFA and select Networkconfiguration. On the Open menu, click SCTP parameters.

The following parameters are displayed, and can be updated:

• Minimum RTO, see Section 4.8.1.8

• Maximum RTO, see Section 4.8.1.5

• Initial RTO, see Section 4.8.1.3

• Alpha, see Section 4.8.1.1

• Beta, see Section 4.8.1.2

• Maximum association retransmissions, see Section 4.8.1.4

• Maximum INIT retransmissions, see Section 4.8.1.6

• Maximum shutdown retransmissions, see Section 4.8.1.7

ConfiguredAlpha or Beta

CorrespondingRTO.Alphaand RTO.Beta

1 0.5

2 0.25

3 0.125

4 0.0625

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• MTU, see Section 4.8.1.9

• Valid cookie life, see Section 4.8.1.10.

To save your changes, click Apply.

Note: To avoid IP fragmentation, you are recommended to set the SCTP MTU toa value that is less or equal to the minimum MTU used in the H.248signaling path (which is normally 1500 octets).

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4 GUI objects

4.1 IP interface

4.1.1 Attributes

4.1.1.1 Administrative state

Description: The administrative state of the IP interface.

• locked – the IP interface is locked, and there are no mediaconnections present on the interface. New connections cannot beestablished over the interface.

• shutting down – the IP interface is locked but there are stillconnections established over the interface. New connectionscannot be established over the interface. When all connections atthe interface have been released, the Administrative stateautomatically changes to locked.

• unlocked – the IP interface is unlocked.

Note: A change of the administrative state will not affect theoperational state. It is possible to have both administrativestate locked and operational state enabled, at the sametime.

4.1.1.2 IP interface address

Entry type: Input fields

Allowable: Integers 0..255

Description: The IP address of the interface.

The following IP addresses and IP address ranges are reserved andtherefore not allowed to be used for media IP addresses:

• 0.0.0.0/8

• 255.255.255.255/32

• 127.0.0.0/8

• 224.0.0.0/4

4.1.1.3 Operational state

Description: The operational state of the IP interface:

• enabled – The IP transport is enabled.

• disabled – The IP transport is disabled. This may, for example,be due to that the underlying ethernet interface is disabled.

Note: A change of the administrative state of the IP interface willnot affect the operational state. It is possible to have bothadministrative state locked and operational state enabled,at the same time.

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4.1.1.4 Port

Entry type: Selection list

Description: The physical Ethernet interface with which the IP interface isassociated. There are two interfaces:

• 0 – first interface

• 1 – second interface.

4.1.1.5 Slot


Description: The slot position of the MGW blade where the IP interface is located.

4.1.1.6 Subnet mask length

Entry type: Input field

Description: The mask length of the subnet to which the IP interface belongs.

4.1.1.7 Subnet segment mask length


Description: The mask length of the subnet segment to which the IP interfacebelongs.

4.1.1.8 Subrack


Description: The subrack of the MGW blade where the IP interface is located.

4.1.1.9 VLAN ID

Description: The VLAN identity of the IS VLAN used for external media transport.

4.1.2 Statistics

4.1.2.1 Discarded, no next hop

Description: Number of outgoing packets that were discarded due to no next hopaddress.

4.1.2.2 Discarded, other reason

Description: The number of received packets that were discarded for otherreasons, that is, one of the following:

• packets received when stream mode is one-way in the oppositedirection or inactive

• RTCP packets received (since RTCP is not supported)

4.1.2.3 Excessive octets

Description: The number of received octets that have been discarded due tobandwidth policing.

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4.1.2.4 Excessive packets

Description: The number of received packets that have been discarded due tobandwidth policing.

4.1.2.5 Filtered packets

Description: The number of received source filtered packets. Packets discardeddue to:

• wrong source address

• wrong protocol (that is, other protocol than UDP)

• wrong RTP version

4.1.2.6 Malicious packets

Description: The number of received malicious packets. The following types ofmedia IP packet are considered malicious:

• Packets sent on an unconfigured media stream (IP address andport).

• Packets with a source address indicating one of the local IPinterface addresses.

• Packets with invalid IP Length field, that is, exceeding thereceived Ethernet payload.

• Packets where the IP options field is used.

• Fragmented packets.

• Packets with unsupported L4 protocol (that is, not UDP).

• Packets with incompatible IP and UDP length (that is, IP lengthnot equal to UDP length + 20 octets) or too short UDP length.

4.1.2.7 Received octets

Description: The number of received accepted octets that shall be forwarded.

4.1.2.8 Received packets

Description: The number of received accepted packets that shall be forwarded.

4.1.2.9 Transmitted octets

Description: The number of octets to be sent. Some of these octets might bediscarded due to traffic management.

4.1.2.10 Transmitted packets

Description: The number of packets to be sent. Some of these packets might bediscarded due to traffic management.

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4.1.3 Buttons

4.1.3.1 Delete IP interface

Description: Deletes the IP interface. Note that the IP interface can only bedeleted if its Administrative state is locked.

4.1.3.2 Graceful lock

Description: Sets the Administrative state of the IP interface to eithershutting down (if there are connections) or locked (if there areno connections). New connections on the IP interface will not beallowed but existing connections remain until they are released.When all connections have been released, the Administrative statechanges to locked.

You can initiate the graceful lock action when the Administrativestate is unlocked.

4.1.3.3 Lock

Description: Sets the Administrative state of the IP interface to shuttingdown (if there are connections) or locked (if there are noconnections). When the IP interface is locked, all existingconnections on the interface will be released. As long asconnections remain on the IP interface, the Administrative statewill remain in the shutting down state. When all connections havebeen released, the Administrative state will change to locked.

When the connections are released, the Gateway Controller (GC)will be informed via notifications about the concerned connectionsover H.248.

You can initiate the lock action when the Administrative state isunlocked or shutting down.

Note: A change of the administrative state will not affect theoperational state. It is possible to have both administrativestate locked and operational state enabled, at the sametime.

4.1.3.4 Unlock

Description: Sets the Administrative state of the IP interface to unlocked.

You can initiate the unlock action when the Administrative state islocked or shutting down.

4.2 Next hop

4.2.1 Attributes

4.2.1.1 Administrative state

Description: Shows the Administrative state of the Next hop.

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• locked – the Next hop is locked, and there are no mediaconnections present over it. New connections cannot beestablished over the next hop.

• shutting down – the Next hop is locked but there are stillconnections established over it. New connections cannot beestablished over the next hop. When all connections on the nexthop have been released, the Administrative state automaticallychanges to locked.

• unlocked – the Next hop is unlocked.

4.2.1.2 Next hop address


Allowable: Integers 0..255

Description: The IP address of the next hop. The following IP addresses and IPaddress ranges are reserved and therefore not allowed to be usedfor next hop addresses:

• 0.0.0.0/8

• 255.255.255.255/32

• 127.0.0.0/8

• 224.0.0.0/4

4.2.2 Buttons

4.2.2.1 Delete next hop

Description: Deletes the next hop. The next hop can only be deleted if itsAdministrative state is locked and if it is not used by a route.

4.2.2.2 Graceful lock

Description: Sets the Administrative state of the Next hop to either shuttingdown (if there are connections) or locked (if there are noconnections). New connections at the next hop will not be allowedbut ongoing connections remain until they are released. When allconnections have been normally released, the Administrative statechanges to locked.

You may initiate the graceful lock action when the Administrativestate is unlocked.

4.2.2.3 Lock

Description: Sets the Administrative state of the Next hop to shutting down(if there are connections) or locked (if there are no connections).New connections at the next hop will not be allowed. When you lockthe next hop by means of this button, all existing connections usingit will be released. As long as there are remaining connections at thenext hop, the Administrative state will remain in the shuttingdown state. When all connections have been released, theAdministrative state changes to locked.

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When the connections are released, the Gateway Controller (GC)will be informed via notifications about the concerned connectionsover H.248.

You can initiate the lock action when the Administrative state isunlocked or shutting down.

4.2.2.4 Unlock

Description: Sets the Administrative state of the Next hop to unlocked.

You can initiate the unlock action when the Administrative state islocked or shutting down.

4.3 Route

4.3.1 Attributes

4.3.1.1 Next hop address

Entry type: Drop-down list

Description: The next hop address is the IP address of the router (ISER) that willforward IP packets to the network defined by the Remote subnetaddress.

4.3.1.2 Remote subnet address


Allowable: 0..255

Description: The IP address of the destination network. The destination networkis a subnet containing the media IP interface addresses of a remoteMGW (or multiple MGWs).

When you specify a default route, that is, a route covering allpossible destination networks, you specify:

• 0.0.0.0

as remote subnet address.

4.3.1.3 Remote subnet mask length


Allowable: 0..32

Description: The subnet mask length of the.remote subnet. That is, the numberof bits in the IP address that are significant.

When you specify a default route, that is, a route covering allpossible destination networks, you specify:

• 0

as remote subnet mask length.

4.3.1.4 Type

Description: The type of route:

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• static route – all the manually configured static routes

• interface route – the routes that are created automaticallyby the system when an IP interface is configured.

4.3.2 Buttons

4.3.2.1 Delete route

Description: Deletes the route.

4.4 Virtual routerThe virtual router contains all the IP interfaces, Routes, and Next hops that havebeen defined for media transport. See Section 4.1, Section 4.2, and Section 4.3 fordetails.

4.5 ARP parameters

4.5.1 Attributes

4.5.1.1 Address collision filter


Allowable: 1..255

Description: The Address collision filter is used to decide when to cease theaddressCollisionAlarm. In this case the parameter specifies thenumber of consecutive ARP requests to be sent without receiving anARP reply before an address collision state ceases and the alarm iscleared.

4.5.1.2 Event filter


Allowable: 1..255

Description: The number of consecutive ARP requests that will be sent withoutreceiving an ARP reply before the next hop peer is considered to bedown, and a nexthopAlarm is issued. It is also used as the numberof consecutive ARP replies received before the next hop peer isconsidered to be up and the alarm is cleared.

4.5.1.3 Poll time collision


Allowable: 1..255

Description: The time between sending gratuitous ARP requests. The valueindicates the number of 100 ms intervals between the requests. Thatis, a value of 10 gives an interval of 1 second.

If an ARP reply is received for any of the gratuitous ARPs or if agratuitous ARP with the same IP address is received from another

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host on the subnet, an address collision state exists and anaddressCollisionAlarm will be sent.

4.5.1.4 Poll time down


Allowable: 1..18000

Description: The time between sending ARP requests when the next hop peer isdown. The value indicates the number of 100 ms intervals betweenthe requests.

4.5.1.5 Poll time up


Allowable: 1..255

Description: The time between sending ARP requests when the next hop peer isup. The value indicates the number of 100 ms intervals between therequests.

4.6 Media supervision

4.6.1 Attributes

4.6.1.1 Hanging media supervision time


Allowable: off, 1 minute – 24 hours

Description: Hanging media is detected when no media (RTP or RTCP) is sent inany stream on a termination for the configured period of time (seethe note below). The time can be specified in the range from 1minute up to a maximum of 24 hours. Setting this object to offdisables the hanging media supervision. When hanging media isdetected the MGW will notify the GC of the hanging media streamsvia H.248.

Note: The hanging media supervision time specifies the intervalbetween two consecutive checks of hanging media in theMGW. That is, when the timer expires, the MGW will checkall its media streams to see whether any streams areinactive. If an individual stream has been inactive duringthe period between two consecutive hanging mediachecks, it will be reported as a hanging media stream tothe GC. This means that the actual time period that thestream has been inactive when the GC is notified may beup to twice as long as the time specified by the Hangingmedia supervision time.

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4.7 H.248 route

4.7.1 Attributes

4.7.1.1 Local subnet segment


Description: The IS subnet segment that will be routed to the destination networkspecified by the Remote subnet address and Remote subnetmask. The Local subnet segment is the subnet segment where theLocal IP address of the associated H.248 Control links is located.The Router address configured for the associated IS subnetsegment will be used as a next hop for the H.248 route.

4.7.1.2 Remote subnet address


Allowable: 0..255

Description: The IP address of the destination network. The destination networkis a subnet containing the H.248 IP interface addresses of a remoteGateway Controller (GC).

The following IP address ranges are not allowed to be used for H.248routes:

• 0.0.0.0/8

• 127.0.0.0/8

• 224.0.0.0/4

4.7.1.3 Remote subnet mask length


Allowable: 0..32

Description: The mask length of the remote subnet. That is, the number of bits inthe subnet address that are relevant.

4.8 SCTP parameters

4.8.1 Attributes

4.8.1.1 Alpha


Allowable: 1..4

Description: Alpha shift factor. Used to compute the Smoothed Round Trip Time(SRTT) for a particular destination address.The alpha shift factor isused as described in Section 3.8.1.

4.8.1.2 Beta


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Allowable: 1..4

Description: Beta shift factor. Used to compute the Round Trip Time Variation(RTTV) for a particular destination address. The beta shift factor isused a as described in Section 3.8.1.

4.8.1.3 Initial RTO


Allowable: 1..1800

Description: The initial value, in seconds, that Retransmission Time-out will take.This value is used before a round-trip time has been calculated. If theRTO timer expires, the message is resent using 2 * RTO as the newtimer value.

4.8.1.4 Maximum association retransmissions


Allowable: 1..20

Description: The maximum number of consecutive retransmissions to a remotepeer from a specific local peer before the peer is considered to bedown.

4.8.1.5 Maximum RTO


Allowable: 1..1800

Description: The maximum value, in seconds, that Retransmission Time-out(RTO) will take. If the RTO timer expires, the message is resent using2 * RTO as the new timer value until the Maximum RTO value isreached. After that the RTO will stay at this maximum level until anew contact with remote peer is reached.

4.8.1.6 Max INIT retransmissions


Allowable: 1..16

Description: The maximum number of retransmissions allowed for the INIT andCOOKIE-ECHO messages. If the Max INIT retransmissions isreached, the sender gives up, sends an ABORT message andcloses the SCTP association.

4.8.1.7 Max shutdown retransmission


Allowable: 1..16

Description: The maximum number of retransmissions during the shutdown of anassociation. When the SHUTDOWN message has been sent theMax shutdown retransmissions number of times, an ABORTmessage is sent and the SCTP association is closed.

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4.8.1.8 Minimum RTO


Allowable: 1..5

Description: The minimum value, in seconds, that Retransmission Time-out(RTO) will take. The RTO will never be decreased below this valueeven if calculations based on measured round-trip times indicatesshorter RTO.

4.8.1.9 MTU


Allowable: 256..9180

Description: The maximum number of octets a user is allowed to pass asnon-fragmented user data in an SCTP message. To avoid IPfragmentation, the value of this attribute should not be set to a valuegreater than the minimum MTU used in the signaling path (which isnormally 1500 octets).

4.8.1.10 Valid cookie life


Allowable: 120..60000

Description: Valid cookie lifetime, in milliseconds, in the 4-way start-uphandshake procedure. The value of this timer must be higher thanthe round-trip time in the network, but as small as possible forsecurity reasons. This parameter sets up the life span of the statecookie sent in the INIT_ACK chunk.

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5 Acronyms and abbreviationsARP Address Resolution Protocol

BS Blade System

DHCP Dynamic Host Configuration Protocol

DiffServ Differentiated Services

DSCP Differentiated Services Code Point

GC Gateway Controller

GUI Graphical User Interface

GVRP GARP VLAN Registration Protocol

ICMP Internet Control Message Protocol

ID Identity

IMS IP Multimedia Subsystem

IP Internet Protocol

IPsec Internet Protocol Security

IS Integrated Site

ISBS IS Internal OAM Boot Network

ISLCT IS Locally Connected Terminal Network

ISM Integrated Site Management

ISOB IS Internal OAM Basic Network

ISOS IS Internal OAM Supplementary Network

L2 Layer 2

L3 Layer 3

L4 Layer 4

LAN Local Area Network

MAC Medium Access Control

MFA Management Function Area

MFAG Management Function Area Guide

MGW Media Gateway

MXB Main Switch Board

OAM Operation and Maintenance

OPI Operation Procedure Instruction

P-bits Priority bits

QoS Quality of Service

RTCP RTP Control Protocol

RTO Retransmission Time-Out

RTP Real-time Transport Protocol

RTTV Round-Trip Time Variation

SAP Service Access Point

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SCTP Stream Control Transmission Protocol

SDH Synchronous Digital Hierarchy

SG Service Guide

SIS Site Infrastructure Support

SONET Synchronous Optical Network

SRTT Smoothed Round-Trip Time

TCP Transmission Control Protocol

TDM Time Division Multiplex

UDP User Datagram Protocol

VLAN Virtual LAN

VR Virtual Router

VRRP Virtual Router Redundancy Protocol

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6 Terms and expressionsBlade pair Two blades in a blade system that work together for call

processor redundancy. One of the blades performs callhandling and the other is stand-by.

Call handling blade The blade that coordinates the resource control of theH.248 call setups. The call handling blade controls theTDM and IP resources of both itself and the stand-byblade. State information of all calls that have been fullyestablished is copied (replicated) to the stand-by blade. Ifthe call handling blade fails, the stand-by blade takes overthe call handling and becomes the new call handling blade.

Core network In this document: The IP network to which the MGW, otherMGWs and the GC are connected.

H.248 control link An H.248 control link represents an H.248 communicationchannel between the media gateway and a gatewaycontroller. The H.248 control link uses SCTP as transportprotocol. The control link may also use SCTP multihomingfor H.248 signaling redundancy.

Interface route A route that represents the subnet where an IP interface islocated. This subnet is directly accessible at the MGWphysical Ethernet interface, which means that no Route orNext hop is needed to reach the subnet. For the MGW,interface routes will be automatically created at IP interfacecreation.

IP interface An entity terminating the IP layer (L3). The IP interface hasan associated IP address.

Next hop A node via which IP traffic is routed. A Next hop is neededwhen an IP source address and an IP destination addressare not in the same subnet, that is, when IP routing isneeded to send an IP packet from the source to thedestination. A next hop address is normally located on theISER, or, if no ISER is used, on an external router.Separate next hops are normally configured for mediatransport and for H.248 signaling. A next hop is normallyassociated with one route but may also be associated withmore than one route.

Route The path(s) IP packets travel on their way to a specificdestination network (IP subnet). A route is thereforedefined by the destination network and is the next hop(s)to use when routing packets to this network. For the MGW,separate routes must be configured for media transfer(Static Route) and for H.248 signaling (H.248 route).Note that a route is only needed when the destinationnetwork of the media transport or H.248 signaling islocated in a subnet other than the associated MGW IPinterfaces for the media or H.248 signaling.

SCTP association A protocol relationship between SCTP end points,composed of the two SCTP end points and protocol stateinformation. An association is uniquely identified by the IPaddresses used by the end points in the association. Onlyone association between two SCTP end points is allowed.For the MGW, an SCTP association is established

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between the MGW SCTP end point and the associatedgateway controller SCTP end point.

SCTP end point The logical sender or receiver of SCTP packets. In theMGW the SCTP end point always has two local IPaddresses to enable SCTP multihoming. For the MGW, aSCTP end point is created when a virtual media gatewayusing SCTP is created. The IP addresses used by anSCTP end point with multihoming will use the same portnumber.

Stand-by blade The blade in a blade pair that serves as a stand-by for thecall handling blade and takes over if the call handling bladefails. The stand-by blade has TDM and IP resources thatare controlled by the call handling blade. When the callhandling blade fails, the H.248 control link, including the IPinterfaces for H.248, is moved to the stand-by blade whichbecomes the new call handler.

Subnet A contiguous IP address range, that is, an IP address or IPprefix, which is the first address in the subnet, and anaddress mask that specifies the size of the subnet. Forexample, the 10.10.10.0/24 subnet has the IP prefix10.10.10.0, and the mask is 24 bits, thus allowing 256addresses within the subnet. A subnet is associated with aspecific VLAN (although more that one subnet are allowedto be associated with the same VLAN).

Subnet segment A subset of the address range within a subnet. Thus, theaddress range of a subnet segment is always smaller than(or equal to) the address range of the associated subnet.The address range of a subnet segment is contiguous anddefined by an IP prefix and an address mask. For example,the 10.10.10.0/24 subnet can be divided into two subnetsegments 10.10.10.0/25 and 10.10.10.128/25. The subnetsegment 10.10.10.0/25 has the IP prefix 10.10.10.0 andthe mask is 25 bits, thus allowing 128 addresses. Theaddress ranges of two subnet segments within a subnetmust not overlap.A subnet segment is normally associated with at least onenext hop address (router address) that is used whensending data to and receiving data from the networks(subnets) outside of IS. This means that dividing a subnetinto subnet segments is, for example, a means to usedifferent routers for different IP interfaces (hosts) within thesame subnet.Note that IP packets can be sent directly between twodifferent IP interfaces (hosts) in two different subnetsegments belonging to the same subnet without goingthrough a router.

Virtual media gateway A logical representation of a media gateway in an MGWblade system. There can be more than one virtual mediagateway within an MGW blade system. A virtual mediagateway controls a set of TDM resources in the systemand has access to all the media transport IP resources (IPaddresses) of the MGW blade system. Each virtual mediagateway has one H.248 control link to a gateway controller.

Virtual router In this document either of:

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– A virtual router in the media gateway, which always existsin one predefined instance and is used to group all thenetwork configuration objects (IP interfaces, Next hops,Routes) needed for a particular network.

– A virtual router used in the ISERs, for example, to groupthe routing configuration data for a particular purpose(H.248 signaling or media transport).

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7 References1. The ISM user interface (1/1551-CNA 113 13 Uen)

2. MFAG: Integrated Site Services (2/155 13-CNA 113 13 Uen)

3. SG, IS services: Network configuration (4/154 43-CNA 113 13 Uen)

4. MFAG: Media Gateway (2/155 13-CNA 113 061 Uen)

5. MFAG: ISER (1/155 13-CNA 113 079 Uen)

6. OPI: Configuring IKE and IPsec (9/1543-CNA 113 079 Uen)

7. SG: Virtual media gateway (17/154 43-CNA 133 061 Uen

8. OPI: Configuring the IS network (5/1543-CNA 113 061 Uen)

9. SN: Network and equipment (7/190 83-CNA 113 056Uen)

10. OPI: Configuring QoS (5/1543-CNA 113 079 Uen)

11. RFC 2960: Stream Control Transmission Protocol

12. ITU-T H.248.1: Gateway control protocol version 3

14/154 43-CNA 113 061 Uen Rev PA43 2006-11-08 49 (49)

Is MGW Network Configuration

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