Post on 26-Oct-2014
ISSUEISSUE
Fixed Network Curriculum
Development Section
Fixed Network Curriculum
Development Section
OWG000003 SIGTRAN protocolOWG000003 SIGTRAN protocol
1.01.0
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ObjectivesObjectives
SIGTRAN application in R4 network
SIGTRAN protocol structure and
message introduction
SIGTRAN signaling flow
Upon completion of this course,you will be able to:
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Course ContentCourse Content
Training.huawei.com
Chap1 overview
Chap2 SCTP protocol
Chap3 M3UA protocol introduction
Chap4 SIGTRAN application
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SIGTRAN definitionSIGTRAN definition
Two layers of protocols are included in the SIGTRAN
protocol stack, i.e., transmission protocols (such as SCTP/IP)
and adaptation protocols (such as M3UA, IUA).
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Introduction of M3UAIntroduction of M3UA
SEP MGC
ISUP
MTP3
MTP2
MTP1
ISUP
M3UA
SCTP
IP
M3UA
SCTP
IP
MTP2
MTP1
SS7 SIGTRANSG
PSTN IP
MTP3
NIF
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Course ContentCourse Content
Training.huawei.com
Chap1 overview
Chap2 SCTP protocol
Chap3 M3UA protocol introduction
Chap4 SIGTRAN application
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Chap2 SCTP protocolChap2 SCTP protocol
1.1 overview1.1 overview
1.2 SCTP terms
1.3 SCTP function
1.4 SCTP message str
ucture
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SCTP protocol introductionSCTP protocol introduction
Stream Control Transmission Protocol (SCTP) is a reliable
transport protocol that operates over a potentially unreliable
connectionless packet service such as IP.
SCTP is designed to transfer SCN narrowband signaling over
IP network.
Compared with the TCP, SCTP features higher reliability,
real-time and multi-homed performance.
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SCTP features SCTP features
Support for orderly/disorderly transmission of subscriber
datagram in the flow.
Multiple streams can be established in one association, and the
data in the streams do not interfere with each other.
Multi-home can be supported at one end or both ends of the
association to improve the reliability of the link.
The association must pass the COOKIE authentication before
establishment to guarantee the security.
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Chap2 SCTP protocolChap2 SCTP protocol
1.1 overview
1.2 SCTP terms1.2 SCTP terms
1.3 SCTP function
1.4 SCTP message str
ucture
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SCTP transmission addressSCTP transmission address
A transport address of Stream Control Transmission Protocol
(SCTP) is defined by the combination of an IP address and an
SCTP port number.
SCTP port number is used for the identification of the users at
the same address, and it is identical to that of TCP port
number in the concept.
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Host and endpointHost and endpoint
A Host is a computer, configured with one or multiple IP addresses.
It is a typical physical entity.
Endpoint is one of basic concepts of SCTP. An endpoint is the
logical sender/receiver of SCTP packets. It is a typical logical entity.
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Association and streamAssociation and stream
SCTPEndpointA
IP/SCTP-port
SCTPEndpointB
IP/SCTP-port
SCTPassociation
SCTPstream(sigleway)
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TSN and SSNTSN and SSN
TSN
Transmission Sequence Number (TSN) is a 32-bit sequence
number used internally by SCTP. One TSN is attached to each
chunk containing user data to permit the receiving SCTP
endpoint to acknowledge its receipt and detect duplicate
deliveries. TSN is maintained on the basis of association.
SSN
SSN is the acronym of Stream Sequence Number. In each strea
m of an SCTP association, a 16-bit sequence number is assigne
d to each data chunk sent in the stream by the local end, in orde
r to ensure the sequenced transmission in the stream. SSN is m
aintained on the basis of stream.
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TSN and SSNTSN and SSN
TSN is maintained on the basis of association.
For example: Endpoint A use two stream to connect endpoint B.
Now block A,B,C,D will be transmit, the sequence of transmission is
as following :block A use stream1,block B use stream2, block C use
stream3, block D use stream4. And block5 is divided into D1 and
D2.
data TSN SSN
A 1 1
B 2 1
C 3 2
D1 4 2
D2 5 2
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CWND and RWNDCWND and RWND
CWND: Congestion Window
An SCTP variable that limits the data, in number of bytes, a
sender can transmit to a particular destination transport address
before receiving an acknowledgement. SCTP is a sliding window
protocol.
RWND: Receiver Window.
An SCTP variable that a data sender uses to store the most rece
ntly calculated receiver window of its peer, in number of bytes.
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Chap2 SCTP protocolChap2 SCTP protocol
1.1 overview
1.2 SCTP terms
1.3 SCTP function1.3 SCTP function
1.4 SCTP message str
ucture
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SCTP functionSCTP function
The functions of SCTP mainly include:
association startup and takedown
sequenced delivery within streams
user data fragmentation
acknowledgement and congestion avoidance
chunk bundling
packet validation
path management.
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Chap2 SCTP protocolChap2 SCTP protocol
1.1 overview
1.2 SCTP terms
1.3 SCTP function
1.4 SCTP message str1.4 SCTP message str
uctureucture
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SCTP messageSCTP message
( COMMON HEADER)+( CHUNK)
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SCTP message typeSCTP message type
Message Name Description
DATA The payload user data
INIT This chunk is used to initiate a SCTP association between two endpoints.
INIT ACK The INIT ACK chunk is used to acknowledge the initiation of an SCTP association.
SACK This chunk is sent to the peer endpoint to acknowledge received DATA chunks and to inform the peer endpoint of gaps in the received
subsequences of DATA chunks.
HEARTBEAT An endpoint should send this chunk to its peer endpoint to probe the reachability of a particular destination transport address defined i
n the present association.
HEARTBEAT ACK An endpoint should send this chunk to its peer endpoint as a response to a HEARTBEAT chunk.
ABORT The ABORT chunk is sent to the peer of an association to close the association.
SHUTDOWN An endpoint in an association MUST use this chunk to initiate a graceful close of the association with its peer.
SHUTDOWN ACK This chunk MUST be used to acknowledge the receipt of the SHUTDOWN chunk at the completion of the shutdown process.
ERROR An endpoint sends this chunk to its peer endpoint to notify it of certain error conditions.
COOKIE ECHO This chunk is used only during the initialization of an association. It is sent by the initiator of an association to its peer to complete the
initialization process.
COOKIE ACK It is used to acknowledge the receipt of a COOKIE ECHO chunk.
SHUTDOWN COMPLETE This chunk is used to acknowledge the receipt of the SHUTDOWN ACK chunk at the completion of the shutdown process
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Startup of associationStartup of association
The startup of SCTP association is a four-way handshake process,
which has four message interactions: INIT, INIT ACK, COOKIE
ECHO and COOKIE ACK
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Termination of associationTermination of association
SCTP association can be terminated in two ways: One is
GRACEFUL close, the other is UNGRACEFUL close.
Just as their names imply, the former means that all data in
queue by either endpoint is delivered to the respective peers
before the association is shut down.
The latter means that the association is directly aborted and
the data is directly discarded.
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Course ContentCourse Content
Training.huawei.com
Chap1 overview
Chap2 SCTP protocol
Chap3 M3UA protocol introduction
Chap4 SIGTRAN application
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Chap3 M3UA protocol introductionChap3 M3UA protocol introduction
3.1 overview3.1 overview
3.2 basic concept
3.3 M3UA message st
ructure
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M3UA functionM3UA function
M3UA (MTP3 User Adaptation) protocol supports the
transport of any SS7 MTP3-User signaling (e.g., ISUP and
SCCP messages) over IP using the services of the Stream
Control Transmission Protocol.
Also, provision is made for protocol elements that enable a
seamless operation of the MTP3-User peers in the SS7 and
IP domains. This protocol would be used between a Signaling
Gateway (SG) and a Media Gateway Controller (MGC) or IP-
resident Database, or between two IP-based applications.
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M3UA protocol introductionM3UA protocol introduction
SEP MGC
ISUP
MTP3
MTP2
MTP1
ISUP
M3UA
SCTP
IP
M3UA
SCTP
IP
MTP2
MTP1
SS7 SIGTRANSG
PSTN IP
MTP3
NIF
SEP: signal endpoint SG: signal gateway MGC:media control
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M3UA protocol introduction(continue)M3UA protocol introduction(continue)
RNC
RANAP
SCCP
MTP-3b
SAAL
ATM
MGW
ATM
SAAL
MTP-3b M3UA
SCTP
IP
SERVER
RANAP
SCCP
M3UA
SCTP
IP
ATM IP
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M3UA protocol introductionM3UA protocol introduction
M3UA also can be used to transfer signaling between two
IPSP
IPMGC MGC
User
M3UA
SCTP
IP
User
M3UA
SCTP
IP
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Chap3 M3UA protocol introductionChap3 M3UA protocol introduction
3.1 overview
3.2 basic concept3.2 basic concept
3.3 M3UA message st
ructure
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Basic conceptBasic concept
AS
A logical entity serving a specific Routing Key.
ASP
A process instance of an Application Server.
IPSP
A process instance of an IP-based application. An IPSP is
essentially the same as an ASP, except that it uses M3UA in a
point-to-point fashion. Conceptually, an IPSP does not use the
services of a Signaling Gateway node.
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Basic conceptBasic concept
M3UA link state transition
M3UA_LINK_INACTIVE
M3UA_LINK_UNESTABLISH
M3UA_LINK_DOWN
Asp Inactive/Asp Inactive Ack/
Asp Alt Notify
Asp Active/Asp Active Ack
M3UA backout successful/Sctp-CDI
M3UA_LINK_ACTIVE
SCTP-RI Asp Down orAsp Down Ackor SCTP-RI
SCTP-CDI
SCTPCDI
M3UA establish successful
Asp Up orAsp Up Ack
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Basic conceptBasic concept
Relationship among M3UA Link, Linkset, Route and Entity
SGP1
SGP2
SGP3
SGP1
SGP2
SGP3
SG1
SG2
MGC
M3UA link set
M3UA route
SP
ASP1
ASP2
ASP3
M3UA linkM3UA entity MTP link
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Basic conceptBasic concept
M3UA route
The path from source entity to destination entity is called a M3U
A route.
One M3UA route corresponds to one M3UA Linkset at the home
terminal.
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Basic conceptBasic concept
M3UA entity
The logical processing unit that accomplishes some special func
tions, such as AS, SP or a logic unit that only implements specia
l message transfer function, such as SG can be classified as M3
UA Entity. Each M3UA Entity is identified by a unique signaling p
oint code.
M3UA LOCAL ENTITY: The logical entity to accomplish speci
al function in local side.
M3UA DESTINATION ENTITY: The logic entity to accomplish
special function in peer side.
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Chap3 M3UA protocol introductionChap3 M3UA protocol introduction
3.1 overview
3.2 basic concept
3.3 M3UA message st3.3 M3UA message st
ructureructure
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M3UA message structureM3UA message structure
The general M3UA message format includes a common message
header followed by zero or more variable length parameters.
The protocol messages for MTP3-User Adaptation require a message
structure, which contains a version, message class, message type,
message length, and message contents.
All the parameters contained in a message are defined in a Tag
Length-Value format as shown below.
Version(8) Reserved(8) Message Class(8) Message Type(8)
Message Length(32)
Parameter Length (16)
Parameter Value(32)
Parameter Tag (16)
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M3UA message introductionM3UA message introduction
Management messages
Transfer messages
SS7 Signaling Network Management messages
ASP State Maintenance messages
ASP Traffic Maintenance messages
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Establishment procedureEstablishment procedure
SGP ASP
ASP UP
ASP UP ACK
AS INACTIVE NOTIFY
ASP ACTIVE
ASP ACTIVE ACK
AS ACTIVE NOTIFY
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Data Transfer procedureData Transfer procedure
Determine the correct Destination Entity.
If the destination Entity is Accessible, then get the Available ro
ute to that destination entity.
Get an Active Linkset belonging to this Route.
Determine an Active Link in the given Linkset.
Determine whether to complete the optional fields of the DAT
A message.
Map the MTP-TRANSFER request primitive into the Protocol
Data field of a DATA message
Send the DATA message to the remote M3UA peer at the SG
P, over the chosen M3UA link.
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MTP_TRANSFER primitive handling at ASPMTP_TRANSFER primitive handling at ASP
MTP_TRANSFER
ASP
Choose the rightlink and map
Transferprimitive to
DATA message
SGP
DATA message
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MTP_TRANSFER handling at SGPMTP_TRANSFER handling at SGP
MTP_TRANSFER
ASP
Choose the rightlink and map
Transferprimitive to
DATA message
SGP
DATA message
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Release procedureRelease procedure
SGP ASP
ASP INACTIVE
ASP INACTIVE ACK
AS PENDING NOTIFY
Pending Timer ExpiresAS INACTIVE NOTIFY
ASP DOWN
ASP DOWN ACK
AS DOWN NOTIFY
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