Hitachi vMME Product Overview
description
Transcript of Hitachi vMME Product Overview
-
vMME Product Overview
Document Number: 10-0100-082
Document Revision Number: 1.02
Document Status: Draft
Issue Date: 2015-05-19
Release Identifier 8.2
Security Status: Hitachi-CTA Confidential
Abstract:
This document provides an overview of the release 8.2 version of the Hitachi vMME product.
-
2015 Hitachi-CTA
All rights reserved.
UNCONTROLLED COPY: The master of this document is stored on an electronic database and is write
protected; it may be altered only by authorized persons. While copies may be printed, it is not
recommended. Viewing of the master electronically ensures access to the current issue. Any hardcopies
taken must be regarded as uncontrolled copies.
HITACHI-CTA CONFIDENTIAL: The information contained in this document is the property of Hitachi-
CTA. Except as expressly authorized in writing by Hitachi-CTA, the holder shall keep all information
contained herein confidential, shall disclose the information only to its employees with a need to know,
and shall protect the information from disclosure and dissemination to third parties. Except as expressly
authorized in writing by Hitachi-CTA, the holder is granted no rights to use the information contained
herein. If you have received this document in error, please notify the sender and destroy it immediately.
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
iii
Publication History
Issue Change Summary Date
1.00 This is the initial draft version of the document. 04/24/2015
1.01 Input 8.2 feature content based on the latest FD documents. 05/04/2015
1.02 Update TS specification versions to Release 11; input feature content based on the
latest FD documents.
05/19/2015
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
iv
Table of Contents
1 About the Document ............................................................................................................................ 1
1.1 Purpose of the Document .......................................................................................................... 1
1.2 What is New in 8.2 Software Release........................................................................................ 1
1.3 Documentation changes ............................................................................................................ 3
1.4 Structure of this document ......................................................................................................... 3
2 Wireless Packet Network Overview..................................................................................................... 4
2.1 GPRS and UMTS network architecture ..................................................................................... 4
2.2 EPS network architecture .......................................................................................................... 6
3 Software Environment ......................................................................................................................... 9
3.1 Operating System ...................................................................................................................... 9
3.2 Application Management ........................................................................................................... 9
3.3 Time Management ................................................................................................................... 10
3.4 OAM ......................................................................................................................................... 10
4 MME/SGSN Software ........................................................................................................................ 12
4.1 Architectural Highlights ............................................................................................................ 12
4.2 Software Components ............................................................................................................. 12
4.3 Management VM ...................................................................................................................... 13
4.4 Resource Manager VM ............................................................................................................ 14
4.5 Call Processing VM .................................................................................................................. 15
4.6 Signaling VM ............................................................................................................................ 18
4.7 Data VM ................................................................................................................................... 20
4.8 Steering Load Balancer VM ..................................................................................................... 21
5 Interfaces ........................................................................................................................................... 22
5.1 Supported Interfaces ................................................................................................................ 22
5.2 Summary .................................................................................................................................. 22
6 Features and Services ....................................................................................................................... 88
6.1 Combined MME/SGSN Node .................................................................................................. 88
6.2 Mobility Management ............................................................................................................... 90
6.3 Customizable Cause Code Mapping ....................................................................................... 95
6.4 Session Management .............................................................................................................. 99
6.5 UE Security Management ........................................................................................................ 99
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
v
6.6 Subscriber Management ........................................................................................................ 101
6.7 User Bearer ............................................................................................................................ 106
6.8 HSPA+ Support ...................................................................................................................... 109
6.9 Direct Tunnel .......................................................................................................................... 109
6.10 Access Sharing .................................................................................................................... 110
6.11 UE Reachability Management ............................................................................................. 114
6.12 UE/MS Purge ....................................................................................................................... 114
6.13 RAN Information Management ............................................................................................ 114
6.14 DNS Support ........................................................................................................................ 115
6.15 SGW, PGW, MME, GGSN and SGSN Selection ................................................................. 117
6.16 Advanced Tracking Area Management................................................................................ 118
6.17 Session-less UE Automatic Detach ..................................................................................... 119
6.18 GGSN Black Listing ............................................................................................................. 119
6.19 Dynamic Load Status Based SGW and PGW Selection ..................................................... 119
6.20 3GPP Trace ......................................................................................................................... 119
6.21 Call Summary Log................................................................................................................ 120
6.22 Subscriber Location Notification .......................................................................................... 120
6.23 P-GW Relocation ................................................................................................................. 121
6.24 Peer node anchor point relocation ....................................................................................... 121
6.25 Accounting Service .............................................................................................................. 122
6.26 Signaling IP Traffic Management ......................................................................................... 125
6.27 1x CSFB Id to eNodeB Mapping .......................................................................................... 126
6.28 Priority Paging for Emergency 1xCSFB Call ....................................................................... 126
6.29 Multiple-SIM Sharing the Same MS-ISDN ........................................................................... 126
6.30 Diameter Based Interface Future Compatibility ................................................................... 126
6.31 Single Radio Voice Call Continuity (SRVCC) ...................................................................... 126
6.32 IMS Emergency Call ............................................................................................................ 127
6.33 VoLTE Support ..................................................................................................................... 128
6.34 Femto Cell Support .............................................................................................................. 129
6.35 Multi-SIM Support ................................................................................................................ 130
6.36 Camel Support and Enhancements ..................................................................................... 130
6.37 Sigtran Enhancements ......................................................................................................... 131
6.38 Unknown RAI Reporting ...................................................................................................... 131
6.39 Multimedia Priority Service .................................................................................................. 131
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
vi
6.40 HSS and PCC Based Network Provided Location Information ........................................... 132
6.41 S6d Override Support and Enhancements .......................................................................... 132
6.42 Non Responsive PGW Quarantine ...................................................................................... 132
6.43 Location Service ................................................................................................................... 133
6.44 TAC level service control ..................................................................................................... 134
7 Carrier Grade Capabilities ............................................................................................................... 135
7.1 Redundancy ........................................................................................................................... 135
7.2 Overload Control .................................................................................................................... 135
7.3 SON Support .......................................................................................................................... 136
7.4 In-service Upgrade ................................................................................................................. 137
7.5 In-service Patching................................................................................................................. 137
8 Operation, Admin and Maintenance Capabilities ............................................................................ 138
8.1 Configuration Management .................................................................................................... 138
8.2 Fault Management ................................................................................................................. 139
8.3 Performance Management .................................................................................................... 139
8.4 CLI .......................................................................................................................................... 144
9 Security Capabilities ........................................................................................................................ 145
10 Capacity ......................................................................................................................................... 146
11 Specification Compliance .............................................................................................................. 147
12 Deployment Examples ................................................................................................................... 148
12.1 Stand-alone MME for a green field LTE operator ................................................................ 148
12.2 Combined MME/SGSN for a G/U operator .......................................................................... 150
12.3 Stand-alone MME for a CDMA Operator ............................................................................. 153
12.4 Stand-alone Gn SGSN for a UMTS only operator ............................................................... 154
13 8.2 Software Release Document Map ........................................................................................... 156
14 References and Related Documents ............................................................................................ 157
14.1 Internal References .............................................................................................................. 157
14.2 External References............................................................................................................. 157
15 Glossary ......................................................................................................................................... 166
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
vii
List of Figures
Figure 1. Gn/Gp Based 3GPP Network Architecture ....................................................................... 4
Figure 2. S4-Based 3GPP Network Architecture ............................................................................. 5
Figure 3. Non-roaming architecture for 3GPP access ..................................................................... 7
Figure 4. Roaming architecture for 3GPP access ............................................................................ 7
Figure 5. Protocol Stack for S1 Interface for Control Plane ........................................................... 24
Figure 6. Protocol Stack for S3 and other Mobility Management interfaces .................................. 28
Figure 7. Protocol stack for S4 interface and other Session Management interfaces ................... 30
Figure 8. Protocol stack for S4 user plane interface ...................................................................... 32
Figure 9. Protocol Stack for S6 interface ........................................................................................ 33
Figure 10. Protocol stack for S11 interface ...................................................................................... 36
Figure 11. Protocol Stack for S13 interface ...................................................................................... 38
Figure 12. Protocol stack for S101 interface .................................................................................... 41
Figure 13. Protocol stack for S102 interface .................................................................................... 42
Figure 14. Protocol Stack for CBC eNB ........................................................................................ 43
Figure 15. Protocol Stack for SGs interface ..................................................................................... 44
Figure 16. Protocol stack for Sv interface ........................................................................................ 46
Figure 17. Protocol Stack for SLg interface ...................................................................................... 47
Figure 18. Protocol Stack for SLs interface ...................................................................................... 48
Figure 19. Protocol Stack for Fxa interface ...................................................................................... 49
Figure 20. Protocol stack for Ga interface ........................................................................................ 50
Figure 21. Protocol stack for Gb interface (IP based transport) ....................................................... 51
Figure 22. Protocol Stack for Gb User Bearer Plane ....................................................................... 55
Figure 23. Protocol Stack for Gd interface ....................................................................................... 57
Figure 24. Protocol Stack for Ge interface ....................................................................................... 61
Figure 25. Protocol Stack for Gf interface ........................................................................................ 63
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
viii
Figure 26. Protocol Stack for GTP-U ................................................................................................ 66
Figure 27. Protocol Stack for Gr interface ........................................................................................ 67
Figure 28. Protocol Stack for Gs interface ....................................................................................... 69
Figure 29. Protocol Stack for Iu User Bearer Plane Anchored on the SGSN ............................... 71
Figure 30. Protocol Stack for Iu User Bearer Plane Direct Tunnel ............................................... 71
Figure 31. Protocol Stack for Iu User Bearer Plane S4-SGSN case ............................................ 72
Figure 32. Protocol Stack for Iu Control Plane ................................................................................. 73
Figure 33. Protocol Stack for Control Plane for UE - MME .............................................................. 78
Figure 34. Protocol Stack for Control Plane MS SGSN in A/Gb Mode ......................................... 82
Figure 35. Protocol Stack for Control Plane MS SGSN in Iu Mode .............................................. 82
Figure 36. Protocol Stack for X interface between the MME and the LIG ....................................... 84
Figure 37. Protocol Stack for HI2 ..................................................................................................... 86
Figure 38. Protocol Stack for Domain Name Service interface ........................................................ 86
Figure 39. Combined MME/SGSN in a wireless network with 2G/3G/4G access technologies ...... 89
Figure 40. National roaming network Example .............................................................................. 104
Figure 41. Deployment example 1 Network Level View ............................................................ 149
Figure 42. Deployment example 1 Nodal level view .................................................................. 150
Figure 43. Deployment example 2 Nodal level view .................................................................. 152
Figure 44. Deployment example 3 Nodal level view .................................................................. 154
Figure 45. Deployment example 4 Nodal level view .................................................................. 155
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
ix
List of Tables
Table 1. vMME Application Software Composition ........................................................................... 13
Table 2. Logical Interfaces ................................................................................................................ 22
Table 3. S1-AP Messages................................................................................................................. 24
Table 4. S3 Interface Messages ....................................................................................................... 28
Table 5. S4 interface GTP-C Messages ........................................................................................... 30
Table 6. S4 User Bearer Plane Messages ........................................................................................ 32
Table 7. S6 Messages ....................................................................................................................... 33
Table 8. S10 Messages ..................................................................................................................... 34
Table 9. S11 interface Messages ...................................................................................................... 36
Table 10. S13 Messages ................................................................................................................. 39
Table 11. S16 Messages ................................................................................................................. 39
Table 12. S101 Interfaces Messages .............................................................................................. 41
Table 13. S102 Interface Messages ............................................................................................... 42
Table 14. SBc Interface Messages ................................................................................................. 43
Table 15. SGs Interface Messages ................................................................................................. 44
Table 16. Sv Interface Messages .................................................................................................... 46
Table 17. SLg Interface Messages ................................................................................................. 47
Table 18. SLs Interface Messages .................................................................................................. 48
Table 19. Fxa Interface Messages .................................................................................................. 49
Table 20. Ga Interface Messages ................................................................................................... 50
Table 21. Gb NS messages ............................................................................................................ 52
Table 22. Gb IP Sub-Network Service Control messages .............................................................. 52
Table 23. Gb BSSGP messages ..................................................................................................... 53
Table 24. SNDCP Messages .......................................................................................................... 55
Table 25. LLC Messages ................................................................................................................ 56
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
x
Table 26. Gd Messages .................................................................................................................. 57
Table 27. M3UA Layer Messages ................................................................................................... 58
Table 28. SCCP Layer Messages ................................................................................................... 59
Table 29. TCAP Layer Messages ................................................................................................... 59
Table 30. Ge Interface messages ................................................................................................... 61
Table 31. Gf Messages ................................................................................................................... 63
Table 32. Gn/Gp Interface Mobility Management Messages .......................................................... 64
Table 33. Gn/Gp Interface Session Management Messages ......................................................... 64
Table 34. Gn/Gp Interface User Bearer Plane Messages .............................................................. 66
Table 35. Gr Messages ................................................................................................................... 67
Table 36. Gs Messages .................................................................................................................. 69
Table 37. Iu Messages .................................................................................................................... 73
Table 38. SCCP Layer Messages ................................................................................................... 76
Table 39. M3UA Layer Messages ................................................................................................... 77
Table 40. NAS Evolved Mobility Management Messages .............................................................. 79
Table 41. Evolved Session Management messages ...................................................................... 80
Table 42. NAS GPRS Mobility Management Messages ................................................................. 83
Table 43. Session Management messages .................................................................................... 83
Table 44. X Interface Messages ..................................................................................................... 85
Table 45. Mobility Scenarios Supported ......................................................................................... 91
Table 46. DNS Procedure and service parameter usage ............................................................. 115
Table 47. 3GPP Technical Specifications ..................................................................................... 122
Table 48. Group Sets and Groups ................................................................................................ 139
Table 49. System Capacity and Performance............................................................................... 146
Table 50. Per Subscriber Capacity ............................................................................................... 146
Table 51. Documentation Map ...................................................................................................... 156
Table 52. External References and Related Documents (3GPP) ................................................. 157
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
xi
Table 53. External References and Related Documents (3GPP2) ............................................... 164
Table 54. External References and Related Documents (IETF)................................................... 164
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
1
1 About the Document
1.1 Purpose of the Document
This document presents the technical information regarding the virtualized combined MME/SGSN
node. The technical detail includes functions and capabilities implemented up to the 8.2 Release.
With virtualization complete, the combined MME/SGSN node is no longer confined to the computing
power of a physical chassis or a frame.
This product can be deployed as a combined MME/SGSN node. In addition, it can also be deployed
as a standalone MME, or a standalone SGSN, depending on the needs of the wireless network
operator. For operators that are currently using earlier releases on Advanced Telecom Computing
Architecture (ATCA) platform, the vMME can be introduced to the MME/SGSN pool and gradually
phase out the ATCA based nodes.
The term vMME in this document refers to the product as a whole, which includes both the MME
function and the SGSN function. When the term MME is used alone, it means the MME function of
the vMME whether it is a standalone MME or part of a combined MME/SGSN. When the term
SGSN is used, it means the SGSN function of the vMME whether it is a standalone SGSN or part of
a combined MME/SGSN. The term S4-SGSN refers to one configuration of the SGSN function that
utilizes the S4 interface for session management. The term Gn-SGSN refers to one configuration of
the SGSN function that utilizes the Gn interface for session management. The SGSN can
simultaneously support Gn-SGSN and S4-SGSN capability.
1.2 What is New in 8.2 Software Release
The following features/functionalities are added in this release:
AGW-21835 Proprietary RAN and NAS cause code to SGW This feature enables the MME to
support the inclusion of RAN/NAS causes in S11 messages: Delete Session Request and Delete
Bearer Command
AGW-23552 EMBMS - This feature implements the Multimedia Broadcast and Multicast Service
(MBMS) specified in TS 23.246 on the MME. MBMS is a point-to-multipoint service which data is
transmitted from a single source entity to multiple recipients. Multiple subscribers can receive the
same data at the same time on the same frequency.
AGW-24378 CLI Initiated Explicit Detach This feature allows the operator to choose the detach
type (implicit or explicit) when clearing the subscriber. Previous functionality performed an implicit
detach.
AGW-24908 MME Collision With this feature, the MME is enhanced to provide the following
collision handling:
-
About the Document
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
2
An enhanced Mobility Management (eMM) procedure (except network initiated Detach)
suspended due to handover (HO) is implicitly completed if the X2 or S1 HO indicates a
Tracking Area Identity (TAI) change.
Radio Link Failure (RLF): When eNodeB (eNB) sends UE Context Release Request with
cause Radio Connection with UE lost during HO, the MME aborts any suspended eMM
and/or enhanced Session Management (eSM) procedures, aborts the HO and releases
all S1 connections. During HO, if the MME receives a UE initiated procedure on a new S1
connection due to RLF, the MME aborts any suspended eMM and/or eSM procedures,
aborts the HO, releases all old S1 connections and processes the UE initiated procedure.
If another X2 or S1 HO request is received while the MME is waiting for the handover-
resource-release-timer to expire or in the middle of cleaning up sessions from the source
Serving Gateway (S-GW) due to S-GW relocation, the new HO request is buffered until
the MME completes cleaning up the sessions on the source S-GW.
UE is implicitly detached by MME when an expected Tracking Area Update (TAU)
Request after HO is not received.
For Mobile Terminated (MT) Circuit Switched Fallback (CSFB) in ECM-Active mode, the
Non-Access Stratum (NAS) CS Service Notification message is queued when MME
receives NAS Non Delivery Indication from the eNB indicating the NAS message is not
delivered due to HO in progress. After HO completes, the MME resends the NAS CS
Service Notification message to the UE.
Home Subscriber Server (HSS) initiated T-ADS Retrieval via Insert-Subscriber-Data-
Request (IDR) is immediately processed by the MME even if the MME is in the middle of
paging, handover or an eMM procedure. The last known TAI for the UE is used to provide
information such as VoLTE support in the Insert-Subscriber-Data-Answer (IDA) message
to the HSS.
AGW-25446 MME 3GPP Interfaces to Release 11 - The MME interfaces are upgraded to be
compliant to the September 2014 version of the Release 11 specifications. Further, for each
interface, an attribute is added to allow the operator to control the version of the interface used by
the node. The operator can use the latest version when the related network nodes are ready to
utilize the new version of the related protocols.
AGW-25498 CLI Ping through Routing Instance This feature provides a CLI command to ping
adjacent 3GPP nodes (an eNodeB) using a configured 3GPP source IP (s1 interface address)
through an LB VM.
AGW-25809 MME LCS Emergency Service Enhancement - This feature enhances the MME
Location Service (LCS) functionality for the emergency. The enhancements are categorized into
configuration, counters, messages and new supported functionality for LCS.
AGW-25811 Inter PLMN Roaming Restriction - This feature enables the network operator to
restrict idle mode inter-node inter-PLMN TAU procedure. The operators are given the ability to
reject or allow the idle mode inter-node inter-PLMN TAU procedure based on the source PLMN
derived from the old GUTI in the TAU request.
-
About the Document
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
3
AGW-25814 GW Blacklisting Enhancements - This feature allows the operator to manually
blacklist SGWs and PGWs and improves the GW selection process by dynamically detecting
failed SGW and PGW.
1.3 Documentation changes
None in this release.
1.4 Structure of this document
The Hitachi vMME is the ultimate mobility management product for the wireless packet network. Its
capabilities span the Evolved Packet System (EPS); aka, 4G networks, as well as the widely
deployed GPRS (2G) and UMTS (3G) packet networks. The rest of the document presents the
capabilities and functions of the vMME.
Wireless Packet Network Overview provides an overview of the wireless packet network from the
standards point of view. Readers familiar with reference network architecture as defined by the 3GPP
standards body should already be familiar with the content of this chapter.
Software Environment provides an overview of the software Environment.
MME/SGSN Software discusses the MME/SGSN software.
Interfaces covers the supported logical interfaces, including both 3GPP defined interfaces and a few
proprietary interfaces.
Features and Services details the features and services provided by the vMME. This chapter also
showcases a rich set of value-add features available on the node. Many of the features are unique in
the industry. Carrier grade capabilities are one of the key differentiators of the vMME and are detailed
within this chapter. To enable ease of use, the vMME also boasts a rich set of OAM capabilities. A
highlight of the key functions is described. To ensure both nodal and end user security, the vMME
supports both network domain and user domain security. The chapter ends with a description of the
capacity and performance of the vMME.
Deployment Examples showcases a few possible network level use cases and related configurations.
This helps the network operators better understand how the vMME can be integrated smoothly into
their networks.
8.2 Software Release Document Map provides a document map for the other documents available to
our customers for this release.
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
4
2 Wireless Packet Network Overview
2.1 GPRS and UMTS network architecture
Prior to the publication of release 8 specifications by 3GPP standards body, the General Packet
Radio Service is a second generation (2G) wireless standard based on a GSM access network and
MAP (Mobile Application Part) core. The Universal Mobile Telecommunications System is a third
generation (3G) wireless standard based on a Code Division Multiple Access (CDMA) access
network and a MAP core.
Since release 8, the traditional network architecture is now referred to Gn/Gp based network whereas
the new network architecture is referred to as S4-based architecture. The following figure shows the
Gn/Gp based architecture as defined by 3GPP specification TS 23.060.
Figure 1. Gn/Gp Based 3GPP Network Architecture
Gf
Uu
Um
D
Gi
Gn
Iu
Gc
C E
Gp
Gs
Signalling Interface (including SMS) Signalling and Data Transfer Interface
TE MT UTRAN TE PDN
Gr Iu
Other PLMN
Gd
SMS-SC SMS-GMSC SMS-IWMSC
GGSN
EIR SGSN
Gn CGF
Ga Ga
Billing
System
Gb
TE MT BSS
R
A
R
gsmSCF
Ge
SGSN
HLR MSC/VLR
GGSN
As part of the release 8 specification, the core network has evolved to be a mixture of MAP and
Diameter core. Further, the wireless architecture is gradually evolving towards a unified packet core
that is embodied in the EPC network architecture discussed in the next section. The R8 based 2G/3G
packet network is referred as the S4-based network.
-
Wireless Packet Network Overview
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
5
Figure 2. S4-Based 3GPP Network Architecture
S13
Uu
Um
D
SGi
S4
Iu
C E
S8
Gs
Signalling Interface (including SMS) Signalling and Data Transfer Interface
MSC/VLR
TE MT UTRAN TE PDN
S6d/Gr (see Note) Iu
HSS
Other PLMN
SGSN
Gd
SMS-SC SMS-GMSC SMS-IWMSC
EIR SGSN
S16
Gb
TE MT BSS
R
A
R
gsmSCF
Ge
P-GW
S-GW
S5
S12
P-GW
In this section we will provide basic introduction to the interfaces that are relevant to the SGSN. The
readers are referred to the 3GPP specifications (mainly TS23.060) for a full discussion of each node
in the network architecture and its interfaces. See section External References.
Regardless of the architecture flavor, the interfaces from the core to the access nodes remain the
same. For the 2G network, the interface between the SGSN and the Access node is the Gb interface.
For the 3G network, the interface between the SGSN and the Access node is the Iu interface. The
interfaces used to bridge the packet network and circuit network are also the same. Additionally,
some SS7 based interfaces remain:
Gs: Interface between the SGSN and MSC/VLR for combined attached subscribers.
Gd: Interface between the SGSN and the SMS Gateway MSC for SMS delivery for the Short
Message Center.
Ge: Interface between the SGSN and the SCF to control UEs usage of the packet network. It is
typically used for prepaid data services.
The interfaces between the packet core nodes have changed from the Gn/Gp based architecture to
S4 based architecture.
-
Wireless Packet Network Overview
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
6
Gn: Interface between the SGSN and GGSN for user session management as well as between
two SGSNs for user mobility management. Another flavor for Gn is Gp, which is the same
interface but between networks belonging to two operators.
S4: Interface between the SGSN and the SGW for session management. S4 supersedes the
session management aspect of the Gn interface when a network moves from Gn/Gp based
architecture to S4 based architecture.
S16: Interface between two SGSNs for user mobility management, replacing the mobility
management aspect of the Gn interface.
Gr: Interface between the SGSN and the HLR for authentication information and subscription
information management.
S6d: Interface in the S4-based architecture between SGSN and the HSS for authentication
information and subscription information management. This interface supersedes the Gr
interface.
Ga: Interface between the SGSN and the CGF for SGSN Accounting.
Gf: Interface between the SGSN and the EIR for equipment validation.
S13: Interface between the SGSN and the EIR for equipment validation. S13 interface replaces
Gf interface in the S4 based 3GPP Network Architecture.
2.2 EPS network architecture
The EPS network evolves from the GPRS and UMTS network. There are a few major changes
compared to the GPRS and UMTS network:
All IP based infra-structure: Not only is the interface between the access nodes and the core
nodes IP based, the interfaces between the core nodes are also all IP based. The Diameter
based protocol replaces MAP based interfaces.
No more circuit domain: Unlike the 2G and 3G network, the 4G EPS network no longer has a
circuit domain that used to provide parallel mobility management for the UEs. Voice services are
achieved using either: IMS (VoLTE) or CS Fallback (SGs).
The following figures show the network architecture as defined by TS 23.401.
-
Wireless Packet Network Overview
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
7
Figure 3. Non-roaming architecture for 3GPP access
SGi
S12
S3
S1-MME
PCRF
Gx
S6a
HSS
Operator's IP Services
(e.g. IMS, PSS etc.)
Rx
S10
UE
SGSN
LTE-Uu
E-UTRAN
MME
S11
S5 Serving Gateway
PDN Gateway
S1-U
S4
UTRAN
GERAN
Figure 4. Roaming architecture for 3GPP access
The following interfaces are related to the MME:
S1-MME: Interface used to connect the E-UTRAN access nodes to the MME for signaling. The data
plane interface is the S1-U between the access nodes to the Serving Gateway.
S3: Interface between the MME and the S4-SGSN for mobility management purpose.
S6a: Interface between the MME and the HSS for subscription and authentication information
management.
S6a
HSS
S8
S3
S1 - MME
S10
UTRAN
GERAN
SGSN
MME
S11
Serving
Gateway UE
LTE - Uu
E - UTRAN
S12
HPLMN
VPLMN
PCRF
Gx Rx
SGi Operators IP Services
(e.g. IMS, PSS etc.)
PDN
Gateway
S 1 - U
S4
-
Wireless Packet Network Overview
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
8
S10: Interface between two MME nodes for inter-MME mobility management.
S11: Interface between the MME and the S-GW for PDN and bearer management. The S-GW
extends the signaling from the MME to the PGW via the S5 or S8 interface.
The readers are referred to TS23.401 for more details on the other interfaces mentioned in the figures
above. Please note, EPC network architecture figures in this section do not cover all the interfaces.
For example, the SGs interface between the MME and the VLR/MSC. This interface allows UE in the
4G network to fall back to 2G GSM or 3G UMTS network for voice call. Another interface not depicted
here is the S13 interface between the MME and the EIR for equipment validation.
In addition to the interfaces discussed above, the vMME also supports other interfaces used to bridge
the existing CDMA 1xRTT network with the 4G E-UTRAN network:
S101: Interface between the HRPD access nodes with the MME to facilitate mobility between the
E-UTRAN network and the HRPD network.
S102: Interface between the MME and the InterWorking System (IWS) to facilitate falling back to
the 1xRTT circuit domain for voice call.
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
9
3 Software Environment
The vMME adopts layered software architecture. From a high level, the system can be divided into
three layers1.
The operating system layer
Platform services (also referred to as middleware) layer
The application layer
This section delves into the function and capability of the Operating System layer and Platform
Services layer. The application layer is detailed in the next section.
3.1 Operating System
The vMME virtual machines run the Linux operating system. The Linux OS is based on the Ubuntu
12.04.2 LTS server distribution, with customization to remove un-needed software. The Linux kernel
from Ubuntu has been optimized to run in the virtual environment, and configured to exclude options
and functions that are not needed. Carrier grade extensions developed by Hitachi are incorporated to
enable the high availability application environment and tools necessary to meet Hitachis stringent
reliability requirements.
The same operating system runs on every virtual machine of the system.
3.2 Application Management
The vMME software is partitioned into several types of virtual machines. One of the virtual machine is
the management VM (or MGMT VM), which is responsible for the Operations, Administration and
Maintenance of a logical vMME node. The six types of virtual machines of the vMME are:
MGMT (OAM)
RM (resource management)
CALLP (call processing, control plane)
DATA (data plane for SGSN)
1 For a virtualized environment, there are other layers of software to support and orchestrate the virtualized
machines. We will not discuss details of that layer of software in this document.
-
Software Environment
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
10
SIG (signaling)
SLB (steering load balancer)
The Application Management software is part of the platform middleware that runs mainly on the
MGMT VM, with local agent on every VM. The Application Management software manages the
lifecycle of application software installed on the system. It is responsible to control the start, stop,
switch of activity of application software entities. Further, it performs monitoring of the application
software to ensure they are running properly.
There can be multiple instances of a VM type. For a given VM type, the redundancy scheme is fixed.
Two types of redundancy schemes are used by the vMME. One is 1:1 active/standby synchronized
redundancy, the other is N-way load shared redundancy. For 1:1 spared VMs such as CALLP and
MGMT, there are up to two units in a VM service pair. For N-way load shared VMs such as DATA, all
the VMs are active while the collection is engineered at capacity and performance of N-1 instances. If
one VM fails, the remaining N-1 VMs are able to take over the capacity without exceeding
engineering limit on each VM.
Each VM contains an aggregation of software functions where each software function represents a
running software resource, for example, a set of processes.
A comprehensive set of CLI commands are supported to allow the operator to configure and manage
the VMs required for a particular vMME.
3.3 Time Management
The vMME uses Network Time Protocol (NTP) to manage time both across the network and within
the system. It is imperative to configure at least one NTP server to ensure that all the nodes in the
network to have synchronized timestamps for all events generated, including charging, fault reporting
etc.
3.4 OAM
For Operations, Administration and Maintenance, the vMME (mme-sgsn) provides the following
functions and northbound interfaces to an NMS (Network Management System):
CM (Configuration Management):
All semantic rules run on the MGMT VM prior to commit
Supports connections via IETF NETCONF
CLI (Command Line Interface): SSH and local serial console
Multiple concurrent CLI and NETCONF sessions are supported
-
Software Environment
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
11
Hierarchical organization of commands and config
Tab based auto-completion and short form on-line help
PM (Performance Management):
One file per node per collection interval
Collection intervals: 5, 15, 30 minutes
CLI access cumulative registers
SFTP pull via external IP address of MGMT VM
Format: 3GPP XML - per 3GPP Technical Specifications: 32.401, 32.404, 32.406,
32.426, 32.432, 32.425
FM (Fault Management):
Customer logs and alarms available by IETF RFC-5424 compliant syslog
Supports SNMPV2 (MIB and OpenNMS eventconf.xml files provided for MME/SGSN)
SNMP and syslog streams presented to NMS via OAM interface of MGMT VM
CSL (Call Summary Log):
One binary file per node per collection interval
SFTP pull of output file via external IP of MGMT VM
Off-board SCTP streaming mode available, recommended for large systems
Captures configurable call release events per UE including
Category: failure, reject, release (abnormal and normal releases), success
Units: mobility, bearer, PDN, radio bearer
TRACE:
Up to ten UE may be configured persistently per: IMSI, IMEI, or MSISDN
One XML file per UE session
SFTP pull of output file via external IP of MGMT VM
Implemented per 3GPP technical specifications: 32.421/422/423
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
12
4 MME/SGSN Software
The vMME software traces its origin back in late 1990s when the GPRS SGSN was first developed.
By the year 2000, the UMTS SGSN completed development and was being deployed in customer
networks worldwide shortly thereafter. With the support for LTE being defined by the 3GPP
organization, our vision for LTE has been to leverage the field-tested and successful SGSN software
base combined with support for MME utilizing common procedures wherever possible. With MME 6.0,
the product can be deployed to customer networks in a combined MME/SGSN configuration, allowing
Operators to reduce operational and capital expenditures by providing high-capacity LTE solutions
while at the same time allowing the same node to manage the 2G and 3G access networks. The
previous release introduced the virtualization technology to the combined MME/SGSN, where the
MME/SGSN is no longer confined to the physical limitations of a chassis.
4.1 Architectural Highlights
The vMME follows the following architectural principle in developing a highly reliable carrier grade
core node:
No single point of failure: From the hardware to platform software to the application software,
redundancy is innate to the design. The system continues to maintain normal service even if there is
a single fault on the system. Furthermore, mobile users that have already attached to the node are
not impacted and continue to receive service.
IP Address efficiency: Despite the high capacity of the vMME, the IP address consumption is at
minimum. Packet steering technology is used within the system to ensure the same IP address can
be serviced by multiple VMs across multiple compute nodes.
Separation of Data and Control: To ensure independent scaling of the signaling load and user bearer
load, the vMME separates control plane software and data plane software on two different sets of
VMs. This ensures CPU resource between the control plane and data plane is properly fenced.
Independent scaling of subscriber capacity and access node connection capacity: The subscriber
capacity and the access node connection capacity are two competing requirements on an MME or an
SGSN. To allow the maximum flexibility, the vMME allows scaling of the two requirements
independently.
4.2 Software Components
The vMME software is grouped based on its function into six different types of virtual machines. Each
virtual machine represents an instance of Linux Operating System running on a compute node that
has a host operating system and a hypervisor. There can be more than one virtual machine on a
single compute node.
-
MME/SGSN Software
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
13
4.2.1 Summary
The details of each type of virtual machine are examined in the ensuing sections. In this section we
provide a tabular view of all the different types that can be configured.
Table 1. vMME Application Software Composition
VM Type Function Max number
of Active per
System
Max total
number per
System
Used by
MME
Used by
S4-
SGSN
Used by
Gn-
SGSN
Management Operations,
Administration and
Maintenance
1 2 Yes Yes Yes
Resource
Manager
Application layer
resource management
1 2 Yes Yes Yes
Call
Processing
Subscriber Control
function
112 22 Yes Yes Yes
Signaling Termination of logical
interfaces
2 20 Yes Yes Yes
Data Handling of user data
plane
15 15 Yes Yes
Steering
Load
Balancer
Handling control plane
IP packet steering
2 8 Yes Yes Yes
For a node that is deployed to support multiple functions, all the required virtual machine types should
be configured. For example, a combined MME/SGSN node that supports both S4-SGSN and Gn-
SGSN capability should have all the VM types present in the system.
4.3 Management VM
The Management VM is the center of Operations, Administration and Maintenance for the vMME. It
runs in 1:1 active/standby mode. It hosts software functions that perform configuration management
of the vMME, collect performance data from the application layer, monitor faults and process status
queries from the operator or the north-bound element manager.
Only one active instance of Management VM and one standby is required.
2 One instance is deployed for Diameter Client use only if the operator wants to use single Diameter instance.
-
MME/SGSN Software
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
14
On top of the above mentioned standard OA&M functions, the Management VM also hosts a couple
of data collection applications. One is the collector for the Call Summary Logs that are generated as
the result of call processing; the other is the collector for the 3GPP Trace data when the activities of
traced subscribers are captured.
4.4 Resource Manager VM
The Resource Manager VM is responsible for managing the application layer resources. It also hosts
single active instance applications on the vMME. The following software functions can be instantiated
on the Resource Manager VM.
4.4.1 Resource Manager
The Resource Manager (RM) manages the global resources of the vMME, which is built on a
distributed virtualized environment. It enables multi-dimensional scaling of subscriber count, access
fan-out and user data throughput. The application software, such as the Subscriber Control in the
CallP VM, needs the resources to manage a slice of the subscribers on the vMME. The Resource
Manager ensures that system resources are utilized to their maximum extent without collision
between the applications on various virtual machines. The Resource Manager is also responsible for
the load-balancing within the cluster of VMs that form one vMME node.
4.4.2 SBc
The MME supports the SBc interface to start, stop and receive Public Warning System (PWS) and
Commercial Mobile Alert System (CMAS) messages from the CBC, and broadcast the message to all
the eNodeBs in the tracking area designated by the CBC. The SBc interface uses the SBc
Application protocol and SCTP as the message transport. The SBc function is responsible for the
following functions:
Maintain up to four SCTP connections to the CBC
Encode/Decode SBc-AP layer messages
Deliver the warning message to the eNodeB with highest priority
Notify the CBC about the message delivery. The response to CBC will not wait for eNodeBs
response to MME
Support redundancy in case of blade failure
Ability to start and stop the broadcasting of PWS and CMAS messages
-
MME/SGSN Software
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
15
The instantiation of SBc function depends on if the operator requires the use of the SBc interface for
emergency broadcasting purpose. If the interface is configured, the vMME instantiates the SBc
function on the Resource Manager VM.
4.4.3 LI
The LI function is used to provide Legal Interception (LI) capability to the vMME. It maintains
connection to the Legal Intercept Gateway which directs the MME/SGSN on the monitoring
information.
The LI function supports the reporting of activity of the UE, known as Intercept-Related Information, or
IRI to the Legal Intercept Gateway (LIG). In the case when user bearer is also established on the
node (SGSN with 2G subscribers, or non-direct tunnel 3G subscribers), the LI function can also report
the communication content of the UE to the LIG if requested.
The LI function is only instantiated if Legal Intercept interface is required and configured on the
vMME.
4.4.4 Ga
The Ga function is used for the SGSN to transfer charging records to the Charging Gateway Function
via the Ga interface. It can also store the charging records locally on the file system for retrieval. The
SGSN can be configured to generate M-CDRs for mobility related records, S-CDR for session related
records and SMS-CDRs for short message service related records. The generated CDR records are
transferred to the CGFs. If the CGFs are down, the records are spooled in the local disk. The spooled
records are replicated on the standby Resource Manager VM.
The Ga function is only instantiated on the Resource Manager VM when the Ga interface is
configured on the vMME.
4.5 Call Processing VM
The Call Processing VM is the signaling processing center of the vMME. It runs in 1:1 active/standby
mode. The key function of the Call Processing VM is subscriber management.
Each vMME can have multiple pairs of Call Processing VMs running in 1:1 spared mode. The
capacity of the vMME grows with the number of Call Processing VMs configured.
The following functions are hosted on the Call Processing VM.
-
MME/SGSN Software
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
16
4.5.1 Subscriber Control
The Subscriber Control (SC) is responsible for processing signaling for the UE, regardless whether it
is originated by the UE or initiated by a network node. The Subscriber Control is the processing
engine for all UE related messages.
The following functions are provided by the Subscriber Control:
Mobility Management
Session Management
Layer 2 Mobility management for optimized active mode handover
The SC process is responsible for handling user signaling. The SC also handles commands received
from the OAM interface, and the CLI interface.
At least one Call Processing VM pair should be deployed on the vMME. For higher subscriber
capacity, more Call Processing VMs can be deployed (up to ten pairs3). Each VM pair is deployed in
1:1 redundancy scheme on two different compute nodes.
4.5.2 Diameter Client
The MME and S4-SGSN utilize the Diameter Clients configured on the MME/SGSN for the S6 (S6a
and S6d) interface, the S13 interface, as well as the SLg interface. The MME or the SGSN requests
the subscription related information via the S6 interface from the HSS. The above mentioned
interfaces use Diameter and SCTP as the message transport. The Diameter Client is responsible for
the following functions:
Maintain the SCTP connections to a set of Diameter peers
Encode/Decode S6,S13 and SLg Application layer messages
Route the messages to the correct SC process
When Diameter protocol is required for the vMME, the Diameter Client is instantiated on at least one
of the CallP VM pairs. For higher Diameter Client processing capability, multiple instances can be
deployed. At maximum, there can be a Diameter Client per CallP VM pair on the vMME.
3 One additional pair of CallP VMs can be deployed if only Diameter Client is enabled on the pair.
-
MME/SGSN Software
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
17
4.5.3 lu
The Iu function provides interface to the 3G access network, or the UTRAN. The Iu function is
responsible for the following:
terminate the RANAP and SCCP layer between the RNC and the SGSN
route the RANAP messages to the correct SC process
manage the SCCP layer connections for UE signaling
Please note, unlike the S1 function which provides connectivity to 4G access network, the Iu function
does not maintain direct SCTP association to the access network. The SCTP associations are fulfilled
by the IPSP function hosted on the Signaling VM discussed in the next section.
The Iu function is instantiated on the CallP VM if the SGSN supports 3G access technology.
4.5.4 SGs
The SGs function is used to terminate the SGs interface between the MME and the VLR. The key
functions of the SGs are:
Maintain SCTP association with the VLRs
Encode/Decode SGs-AP layer messages
Route the message to the current Subscriber Control
The SGs function can be instantiated on the CallP VM when the SGs interface is configured.
4.5.5 SLs
The SLs function is used to terminate the SLs interface between the MME and the eSMLC. The key
functions of the SLs are:
Maintain SCTP association with the eSMLCs
Encode/Decode LCS-AP layer messages
Route the message to the current Subscriber Control
The SLs function can be instantiated on the CallP VM when the SLs interface is configured.
-
MME/SGSN Software
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
18
4.6 Signaling VM
The Signaling VM is responsible for terminating the logical interfaces with an external node. All the
interfaces hosted on the Signaling VM use N-way load-sharing redundancy. As such, multiple active
instances of a signaling VM can be deployed on the vMME. The higher the number of Signaling VMs,
the higher the fan-out and signaling processing capability of the vMME.
The following functions are hosted on the Signaling VM.
4.6.1 S1
The S1 function provides interface to the 4G access network, or the E-UTRAN. The S1 is responsible
for the following:
receive and maintain SCTP connections from the eNodeBs that are in the service area of the
MME
terminate the S1-AP layer
route the S1-AP messages to the correct SC process
The instantiation of the S1 function on the Signaling VM depends on whether the vMME is used to
support 4G Access technology or not.
4.6.2 UDP Path Manager (UPM)
The UPM function is used to process all GTP-C based interfaces, as well as other UDP based
interfaces, including the following:
S11
S10
Fxa (Radius based)
S3
S4
S16
Sv
Gn/Gp
S101
S102
-
MME/SGSN Software
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
19
Details of afore-mentioned interfaces are discussed in Supported Interfaces.
The function of UPM includes:
For GTP based protocols:
GTP-Path Management
Decoding/Encoding GTP headers
Routing the GTP messages to the correct SC process
For RADIUS based protocols (Fxa):
RADIUS Fxa Path Management
Routing the messages to the correct SC process
1x CS based protocol
S102 Path Management
Relay S1AP CDMA2000 messages between the MME and IWS
Routing the messages to the correct SC process
4.6.3 TCAP
The Transaction Capabilities Application Part (TCAP) application provides a communication channel
towards an SS7-based network for a number of applications that are based on MAP.
The TCAP function supports the Gf, Gr, Ge and Gd interfaces.
The instantiation of the TCAP function depends on if SS7 signaling is used for the SGSN.
4.6.4 SIGTRAN
The SIGTRAN function (also referred to as SIGTRAN ASP or ASP) implements the M3UA layer, and
provides signaling transport over an IP network for the Gr, Gs, Gf, Ge and Gd interfaces to the HLR,
MSC/VLR, EIR, SCF and SMSC. This application provides support for both ANSI and ITU based
signaling.
Similar to TCAP, the instantiation of the SIGTRAN depends if SS7 signaling is required or not on the
vMME.
-
MME/SGSN Software
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
20
4.6.5 IPSP
The IPSP function is used to provide M3UA connectivity to the 3G access network, or the UTRAN to
support the Iu function that runs on the CallP VM. It provides the M3UA layer function for the Iu
function discussed above. The IPSP function maintains SCTP associations with the peer M3UA
based peer node. The IPSP further routes the incoming messages based on the destination point
code to the correct Iu function residing on the right CallP VM.
The instantiation of IPSP depends on whether 3G access technology is supported on the vMME or
not.
4.7 Data VM
The Data VM is used only with the SGSN function to support 2G or 3G user data packets. Multiple
active instances are configured to support the needed throughput required for the SGSN. When 2G
access technology is required, it is recommended to be configured in pairs to provide redundant
connectivity to every 2G BSS node. Otherwise, any number of active instances of Data VM can be
configured.
The following functions are hosted on the Data VM.
4.7.1 Gb
The Gb function provides the Gb interface to the 2G access network, or the GERAN. It terminates
both the BSSGP layer and NS layer towards the BSS. The SGSN IP based NS layer. It can be used
to connect to BSS nodes that support IP based Gb interface directly via an IP backbone network. The
instantiation of the Gb function depends on whether connectivity to a 2G access network is required.
To provide redundancy, two Data VMs should be used to connect to the same BSS node. The two
data VMs support the same set of BSS nodes and run in active/active load-sharing redundancy
mode. The two VMs are synchronized with regard to the connectivity information to the BSSs.
Connectivity to the BSS is maintained as long as one of the two VMs is in service.
4.7.2 Subscriber Data
The Subscriber Data (SD) function provides user bearer service on the SGSN. For 3G subscribers, it
acts as a split tunnel that relays user packets from the GGSN to the RNC and vice versa. For 2G
subscribers, it provides additional services. The services include:
Link layer: The SD function supports both acknowledged and unacknowledged LLC layer
between the UE and the SGSN. Additionally, it performs ciphering/de-ciphering based on agreed
ciphering algorithm on the link layer frames.
-
MME/SGSN Software
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
21
SNDCP layer: This layer bridges the LLC layer and the IP layer for the UE. The SD function can
provide both header compression and V.42bis data compression at this layer to reduce the data
size over the air.
The SD function is required for the SGSN. It is instantiated on every Data VM unless the data VM is
used for SGSN specific signaling functions below.
4.8 Steering Load Balancer VM
The SLB VM, or LB VM, forwards ingress packets to the 3GPP address of the target VMs. On the
SLB VM, the LBCtrl process programs steering policies into a forwarding infrastructure running within
the SLB VM kernel. This configuration is used to steer incoming traffic to specific target VMs.
Two or more (up to eight) SLB VMs can be instantiated on separate hosts. All policies are
programmed on each SLB VM allowing the ability to load balance ingress 3GPP traffic across all SLB
VMs. Egress traffic is handled on the target VM by routing the packets back to the SLB VM using
multi-path routing (in order to load balance the egress 3GPP traffic). 2G and 3G user data does not
transverse the SLB VM and is routed directly to the target Data VMs with a static route configured in
the next-hop router/L3-capable switch.
-
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
22
5 Interfaces
5.1 Supported Interfaces
The vMME supports a plethora of interfaces that make it the most flexible mobility management core
node on the market. It can be deployed as a legacy 2G-only SGSN, 3G only SGSN, a combined
2G/3G SGSN, an S4-based SGSN, a standalone MME (suitable for both current CDMA operators as
well as GPRS/UMTS operators) or a combined 2G/3G/4G MME/SGSN.
In this section, we will discuss the characteristics of each interface supported. The sub-section below
captures the summary of all interfaces while the ensuing sub-sections provide an in-depth look for
each interface.
5.2 Summary
As a combined MME/SGSN, the vMME supports an extensive array of 3GPP defined interfaces as
well as a few value-added proprietary interfaces. The following table provides a condensed view of all
the logical interfaces available on the MME/SGSN. The ensuing sections provide a more detailed
view of each interface.
Table 2. Logical Interfaces
Interface
Name
Peer Node Relay Node Local IP Usage
Name Cardinality Name Cardinality Min Max Type
S1 eNodeB 25000 N/A 1 4 IPv4 and IPv6
S3 SGSN or
MME
1000 N/A 14 2 IPv4 and IPv6
S4 SGW 1000 N/A 1 2 IPv4 and IPv6
S6 HSS 1000 if via
Relay
248 if direct
connect
Diameter
Agent
248 1 20 IPv4 or IPv6
S10 MME 1000 N/A 1 2 IPv4 and IPv6
S11 SGW 1000 N/A 1 2 IPv4 and IPv6
4 The IP addresses of a GTP-C based interface can be shared with other GTP-C interfaces. Thus the minimum
IP consumption for all the interfaces sharing the IP addresses can be 1 in total, instead of 1 for every interface.
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
23
Interface
Name
Peer Node Relay Node Local IP Usage
Name Cardinality Name Cardinality Min Max Type
S13 EIR 1 Diameter
Agent
248 Shared with S6. IPv4 or IPv6
S16 SGSN 1000 N/A 1 2 IPv4 and IPv6
S101 eAN 15000 N/A 1 2 IPv4 and IPv6
S102 IWS 200 N/A 1 2 IPv4 and IPv6
SBc CBC 4 N/A 1 2 IPv4 or IPv6
SGs VLR 256 N/A 1 2 IPv4 or IPv6
Sv VLR 256 N/A 1 2 IPv4 and IPv6
SLg GMLC 50 DRA 248 Shared with S6. IPv6 and IPv6
SLs eSMLC 20 N/A 1 2 IPv6 or IPv6
Fxa AAA 128 N/A 1 1 IPv4 or IPv6
Ga CGF 2 N/A 1 1 IPv4
Gb BSS
(PCU)
600 N/A 1 15 (GbIP)
IPv4
Gn/Gp
(tunnel)
GGSN 1000 N/A 1 2 IPv4 and IPv6
Gn/Gp
(mobility)
SGSN 1000 N/A 1 2 IPv4 and IPv6
Gn/Gp
(user
bearer)
GGSN No limit N/A 1 15 IPv4
Gd SMS-
GMSC or
SMS-
IWMSC
No limit M3UA
peer
500 1 10 IPv4
Ge SCP 128
Gf EIR 1
Gr HLR 1000
Gs VLR 2565
Iu
(signaling)
RNC 4096 M3UA
peer
8192 1 40 IPv4
Iu (user RNC No limit N/A 1 15 IPv4
5 Shared with the SGs interface for a combined MME/SGSN.
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
24
Interface
Name
Peer Node Relay Node Local IP Usage
Name Cardinality Name Cardinality Min Max Type
bearer)
NAS UE 4,160,000 Access Node (See Gb,
Iu and S1)
0 0 N/A
X1 LIG ADMF 1 N/A 1 1 IPv4 or IPv6
X2/X3 LIG DF 1 N/A
DNS DNS
Server
8 N/A 1 1 IPv4 or IPv6
5.2.1 S1 Interface
The S1 Interface allows the eNodeBs to communicate with the Evolved Packet Core network. The
interface is split between S1-MME (also referred to as S1-C) for Control plane and S1-U for User
plane. The MME only terminates the S1-MME, whereas the Serving Gateway terminates the S1-U.
The following figure shows the protocol stack for S1-MME.
Figure 5. Protocol Stack for S1 Interface for Control Plane
For the S1 interface, the peer node for the MME is the eNodeB.
The MME allows the operator to configure the version of the S1-AP specification to be used over the
S1 interface. The supported versions of TS36.413 are: V9.5.1, 10.6.0 or 11.8.0. The following table
shows the messages supported for each of the configured versions.
Table 3. S1-AP Messages
S1-AP
SCTP
IP
L2
L1
eNodeB
S1-MME
MME
S1-AP
SCTP
IP
L2
L1
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
25
# Message Type Message
Direction
V9.5.1/V10.6.0/V11.8.0
1 E-RAB Setup Request eNB MME Supported
3 E-RAB Modify Request eNB MME Supported
5 E-RAB Release Command eNB MME Supported
7 E-RAB Release Indication eNB -> MME Supported
8 Initial Context Setup Request eNB MME Supported
10 Initial Context Setup Failure eNB -> MME Supported
11 UE Context Release Request eNB -> MME Supported
12 UE Context Release Command eNB MME Supported
14 UE Context Modification Request eNB MME Supported
16 UE Context Modification Failure eNB -> MME Supported
17 Handover Required eNB -> MME Supported
18 Handover Command eNB
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
26
# Message Type Message
Direction
V9.5.1/V10.6.0/V11.8.0
36 Reset eNB MME Supported
37 Reset Acknowledge eNB MME Supported
38 Error Indication eNB MME Supported
39 S1 Setup Request eNB -> MME Supported
40 S1 Setup Response eNB MME Supported
62 MME Direct Information Transfer eNB MME Supported
64 MME Configuration Transfer eNB MME Not supported
66 Kill Request eNB MME Supported
68 Downlink UE Associated LPPA Transport eNB MME Supported
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
27
# Message Type Message
Direction
V9.5.1/V10.6.0/V11.8.0
70 Downlink Non UE Associated LPPA
Transport
eNB MME Supported
At the SCTP layer, the MME supports multi-home function as well as SCTP association recovery
capability required by TS36.412. For the multi-home support, up to two IP addresses are supported at
the local end-point or the remote end-point. The two IP addresses for the same multi-home
association must be of the same IP address type (either IPv4 or IPv6). Mixture of IPv4 address and
IPv6 address for the same SCTP association is not supported. The MME also supports configurable
number of streams for both directions.
At the IP layer, the MME supports both IPv4 and IPv6 addresses at the same time, thus allowing
connectivity to both IPv4 eNodeBs and IPv6 eNodeBs simultaneously. At the minimum consumption,
only a single local IPv4 address is required. At maximum, two local IPv4 addresses and two local
IPv6 addresses are used to support SCTP multi-home to IPv4 eNodeBs and IPv6 eNodeBs.
The maximum number of eNodeBs that the MME can connect to is 25,000 in this release.
5.2.2 S3 Interface
The S3 interface facilitates the UE mobility between an S4-SGSN and an MME. This interface along
with mobility interfaces between the S4 SGSNs (S16), Gn-SGSN (Gn/Gp), and between the MMEs
(S10) is based on the prevalent GTP protocol. For the S-based EPC interfaces, GTPv2 is used. For
the legacy Gn/Gp interface, GTPv1 is used.
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
28
Figure 6. Protocol Stack for S3 and other Mobility Management interfaces
The peer node for the S3 interface is either the MME if this node is acting as the source or old SGSN,
or the SGSN if this node is acting as the source or the old MME.
The vMME allows the operator to configure the specification version of the GTPv2 to be used over
the S3 interface. The same version is also used for the S10/S16 interfaces. The supported versions
of TS 29.274 on the MME/SGSN are: V9.5.0, V10.10.0 and V11.13.0. The following table shows the
messages supported for each of the configured versions.
Table 4. S3 Interface Messages
# Message Type Message Direction V9.5.0/V10.10.0/V11.13.0
1 Echo Request Source SGSN -> Target MME,
Source MME -> Target SGSN
Supported
2 Echo Response Source SGSN
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
29
# Message Type Message Direction V9.5.0/V10.10.0/V11.13.0
8 Context Acknowledge Source SGSN Target SGSN
Supported
10 Forward Relocation
Response
Source SGSN Target SGSN
Supported
12 Relocation Cancel
Response
Source SGSN
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
30
5.2.3 S4 Interface
The S4 interface is used for session management between the S4-SGSN and the SGW. This
interface along with the other session management interfaces between the Gn SGSN and the GGSN
(Gn/Gp) or between the MME and the SGW (S11) is based on the GTP protocol. For the S-based
EPC interfaces, GTPv2 is used. For the legacy Gn/Gp interface, GTPv1 is used.
Figure 7. Protocol stack for S4 interface and other Session Management interfaces
The peer node for the S4 interface is the SGW. The versions supported in this release are TS29.274
V9.5.0 and TS29.274 V10.10.0. The following table shows the messages supported for each of the
configured versions.
Table 5. S4 interface GTP-C Messages
# Message Type Message Direction V9.5.0/V10.10.0
1 Echo Request S-GW SGSN
Supported
2 Echo Response S-GW SGSN
Supported
3 Create Session Request S-GW SGSN Supported
5 Create Bearer Request S-GW -> SGSN Supported
6 Create Bearer Response S-GW
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
31
# Message Type Message Direction V9.5.0/V10.10.0
10 Modify Bearer Response S-GW -> SGSN Supported
11 Delete Session Request S-GW SGSN Supported
13 Delete Bearer Request S-GW -> SGSN Supported
14 Delete Bearer Response S-GW SGSN Supported
16 Downlink Data Notification Acknowledge S-GW S-GW Supported
38 Trace Session Deactivation SGSN -> S-GW Supported
39 Change Notification Request S-GW -> SGSN Not supported
40 Change Notification Response SGSN -> S-GW Not supported
41 Delete PDN Connection Set Request SGSN S-GW Not supported
42 Delete PDN Connection Set Response SGSN S-GW Not supported
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
32
At the GTP layer, the vMME supports up to 1000 peers for session (or tunnel) management purpose.
Each peer is represented by a unique IP address of the peer. Path management function is used to
monitor the health and/or reach-ability of the peer node. For the S4 interface, DNS procedures as
defined in TS29.303 are used for the discovery of the peer IP addresses.
At the IP layer, the SGSN supports both IPv4 and IPv6 addresses at the same time, thus allowing
connectivity to both IPv4 SGW and IPv6 SGW at the same time. Up to two local IP addresses (one
IPv4, one IPv6) are needed for the S4 interface. If only IPv4 is used by all the peer nodes, then the
IPv6 address is not required. The local IP addresses can be shared with all other GTP-C based
interfaces.
Figure 8. Protocol stack for S4 user plane interface
The SGSN uses only one local IPv4 address for the purpose. The number of IP addresses that can
be used by the GGSNs is not limited. The following table shows the messages supported.
Table 6. S4 User Bearer Plane Messages
# Message Type Message Direction V9.3.0
1 Echo Request SGSN GGSN Receive only
2 Echo Response SGSN GGSN Supported
3 Error Indication SGSN GGSN Supported
4 Supported Extension Header Notification SGSN GGSN Supported
5 G-PDU SGSN GGSN Supported
GTP-U
UDP
IP
L2
L1
SGSN
S4 user plane
SGW
GTP-U
UDP
IP
L2
L1
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
33
5.2.4 S6 Interface
The S6 interface permits the MME or SGSN to retrieve the Authentication information and
Subscription data from the Home Subscriber Server (HSS). The interface between the MME and the
HSS is referred to as S6a, and the interface between the SGSN and the HSS as S6d. In this
document, S6 is used to refer to both.
The following figure shows the protocol stack used by the S6 interface.
Figure 9. Protocol Stack for S6 interface
The peer node for the S6 interface is the HSS. The vMME can connect directly to the HSS nodes, or
indirectly via a set of Diameter Agents. The vMME has a limitation of 248 direct connected peer
nodes. If all the HSSs are directly connected, then the total number is limited to 248. However, if
Diameter Agents are used, the number of HSSs that can be supported is 1000.
The vMME allows the operator to configure the specification version of the S6 to be used. The
supported versions of TS.29.272 are: V9.5.0 ,V10.7.0 and 11.11.0. The following table shows the
messages supported for each of the configured versions.
Table 7. S6 Messages
# Message Type Message Direction V9.5.0/10.7.0/11.11.0
1 Update Location Request Command HSS MME/SGSN Supported
3 Authentication Information Request Command HSS MME/SGSN Supported
5 Cancel Location Request Command HSS -> MME/SGSN Supported
6 Cancel Location Answer Command HSS MME/SGSN Supported
S6
Diameter
SCTP
L2
L1
MME/SGSN
S6
HSS
S6
Diameter
SCTP
L2
L1
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
34
# Message Type Message Direction V9.5.0/10.7.0/11.11.0
8 Insert Subscriber Data Answer Command HSS MME/SGSN Supported
10 Delete Subscriber Data Answer Command HSS -> MME/SGSN Supported
11 Purge UE Request Command HSS MME/SGSN Supported
13 Reset Request Command HSS -> MME/SGSN Supported
14 Reset Answer Command HSS
-
Interfaces
vMME Product Overview
Document Status: 8.2, Draft Hitachi Proprietary and Confidential
35
3 Identification Request Old MME New MME Supported
5 Context Request Old MM