0aa000009 sigtran protocol issue2.0

7/30/2019 0aa000009 Sigtran Protocol Issue2.0

1/37

ISSUE

Fixed Network Curriculum

Development Section

OAA000009 SIGTRAN ProtocolPrinciple

2.0


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Confidential Information of Huawei.No Spreading without Permission. Security Level: Internal

2

Objective

Functions and structures of SIGTRAN

protocols

Commands of each protocol of

SIGTRAN protocol stack

Meanings and usage of the parameters

in commands

Message interaction process of each

protocol

After this session, you will learn:


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3

References

Product Manual -- Technical Manual -- Signaling and

Protocols Chapter 2 SIGTRAN


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About this session

Section 1 Overview

Section 2 SCTP Protocol

Section 3 M2UA Protocol



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Definitions of SIGTRAN Protocols

SIGTRAN is

a protocol stack rather than a protocol.

It includes

transmission protocol (SCTP)

adaptation protocols (M2UA and M3UA).

SIGTRAN supports transmission of SCN (Switched Circuit

Network) signaling via IP network.

SIGTRAN is responsible for the communication between

SG and MGC, with such two functions as adaptation

transmission


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SIGTRAN Protocol Stack Structure

SCTP

IP

MAC

M3UA M2UA IUA M2PA V5UA SUA

M3UA: MTP3 UserAdaptation layer


IUA: ISDN Q.921 UserAdaptation layer

M2PA: MTP2 PeerAdaptation layer

V5UA: V5 UserAdaptation layer

SUA: SCCP UserAdaptation layer


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Section 1 Overview

SIGTRAN Applications in SoftX3000

Terms

Protocol Structure


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PSTN SoftX3000

TMG

SG

Signaling stream

Media stream

SS7SIGTRAN

H.248

Switched Circuit Network Packet Switched Network

IP core network


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Section 1 Overview


Terms

Protocol Structure


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Terms

MG

MGC

SG


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Section 1 Overview


Terms

Protocol Structure


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Protocol Structure in SoftX3000

When SoftX3000 uses M2UA of the SIGTRAN protocol

stack to connect with SG:

SEP SG SoftX3000IP

ISUP

MTP

1-2

M2UASCTP

IP

M2UASCTP

IP

ISUP

MTP1-2

MTP3

MAC MAC

MTP3


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Question

What are the main functions of SIGTRAN?

What protocols are used to realize these

functions?


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Answer

The main functions of the SIGTRAN

protocol stack are transmission and

adaptation. The transmission function is

realized via SCTP while the adaptation

function is realized via M2UA and M3UA

protocols.


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Brief Summary

SIGTRAN is a protocol stack that mainly includes three

protocols: SCTP, M2UA and M3UA.

The SIGTRAN protocol stack is responsible for the

communication between SG and MGC, with such twofunctions as adaptation and transmission .

In NGN softswitch system, SIGTRAN is used to bear and

adapt interworking between SS7 of SCN and IP network

softswitch control system, acting as a bridge for

signaling conversion.


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About this session

Section 1 Overview





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SCTP Overview

SCTP(STREAM CONTROL TRANSMISSION PROTOCOL) is areliable datagram transmission protocol based on the protocol

providing unreliable transmission services, such as IP.

The SCTP is designed to transmit PSTN signaling messages

over the IP network.

SCTP improves some defects of TCP.

The design of SCTP includes proper congestion control, flooding

prevention, disguise attack and support to better real-time

performance and multi-homing attribute.

The SCTP is usually regarded as a transmission layer protocol,

whose upper layer is SCTP user application

lower layer is packet-switched network (for example, IP network).


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SCTPOverview

Transport address and IP address:

A transport address of SCTP is

IP address : SCTP port number.

SCTP port number is used for the identification of the users at the

same address, and it is identical to the concept of TCP port number.


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OverviewSCTP Terms

Host and endpoint:

SCTP

IP

A

d

d

r

e

s

s1

P

O

RT

1

User 1

User 2

EndPoint1

EndPoint2

Host

P

O

RT

2

IP

A

d

d

r

e

s

s

2


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About this session

Section 1 Overview





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Concepts

M2UA ---- SS7 MTP2-User Adaptation Layer Protocol

is a protocol for the transport of SS7 MTP2 user signaling

messages (MTP3 messages) over IP using SCTP or any

other suitable transport protocol.

Used between Signaling Gateway (SG) and Media Gateway

Controller (MGC).


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Concepts

SEP MGC

ISUP

MTP3

MTP2

MTP1

ISUP

MTP3

M2UA

SCTP

IP

M2UA

SCTP

IP

MTP2

MTP1

SS7 SIGTRANSG

PSTN IP


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Concepts

Name Description

Interface ID Used in the communication between the two ends of M2UA. It can be text

or integer. Each interface ID corresponds to one actual physical link: An

interface is the logical ID of an SS7 signaling link used between SG and

ASP.

Application server A logical entity representing certain resources and corresponding to a

specific routing context. For M2UA, AS is a group of Interface IDs.

Every AS includes a set of ASPs, and one or more of which can process

traffic

Application Server

Process

ASP is a process instance of an AS. Each ASP contains one SCTP

endpoint, and can serve a number of ASs. In the M2UA application, ASPs

work in the active/standby mode, and only the active ASP processes

traffic.

Signaling Backhaul It refers to transfer of non-local signaling from the interface connecting

with the data stream (i.e. the SG function of MGU) back to the call

processing point (i.e. MGCU)


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Item -- M2UA Link

M2UA LINK: t

The logical connection established between SG and ASP.

A Link consists of SG, ASP and SCTP associations

between SG and ASP.

Its state corresponds to ASP state and SCTP association

state


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Item -- M2UA Link

MG/SG0

MTP2 link 0

MTP2link 1

MTP2 link 2

MTP2 link 3

ASP0

ASP1

ASP2

ASP3

SCTP assoc 0

SCTP assoc 1

SCTP assoc 2

SCTP assoc 3

AS0

AS1

AS0 includes MTP2 link0 and link 1

AS1 includes MTP2 link2 and link 3

MGC


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Item -- M2UA Link

MG/SG0

MTP2 link 0

MTP2 link 1

MTP2 link 2

MTP2 link 3

M2UA LINK 0(servered for MTP2 link 0and link1)AS0

AS1

M2UA LINK 1(servered for MTP2 link 2and link3)

MGC


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Item -- M2UA Function

Support for MTP2/MTP3 interface boundary that enables

a seamless, or as seamless as possible, operation of the

MTP2 users in the PSTN and IP network.

Support for management layer communication betweenSG and MGC.

Support for management of SCTP association between

SG and MGC.


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About this session

Section 1 Overview





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Overview

Services provided by M3UA


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Concepts

M3UA is the SS7 MTP3 user adaptation layer

providing the primitive communication service for the MTP3

user in the IP network and MTP3 at the network edge

interworking between TDM SS7 and IP .

M3UA supports the following functions:

SS7 SPC presentation

Routing function

Interworking between SS7 and M3UA

Congestion management

SCTP stream mapping

Client/server model


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ConceptArchitecture of M3UA Protocol

SCTP

IP

MAC

M3UA M2UA IUA M2PA V5UA SUA



IUA: ISDN Q.921 UserAdaptation layer

M2PA: MTP2 PeerAdaptation layer

V5UA: V5 UserAdaptation layer

SUA: SCCP UserAdaptation layer


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Concept -- M3UA Application

M3UA application in SGP-ASP mode:

SS7ISEP

IITP1

TP2

TP3

IMTPUser

MTP3

MTP2

MTP1


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M3UA Application

M3UA application in IPSP-IPSP mode:

IMGC

User

M3UA

SCTP

IP


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Overview



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Support for the transport of MTP3 user messages

Local management functions

Interworking with MTP3 network management function

Support for the management of SCTP associations

between SGP and ASPs

Support for the management of associations to multiple

SGPs


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Summary of the Chapter

SIGTRAN is a protocol stack consisting of SCTP, M2UA and

M3UA. SIGTRAN itself is not a protocol

Compared with TCP and UDP, SCTP has lots of advantages in

reliability, security and real-time performance, and it supports

multi-homing feature. SCTP is used as the bearer transportlayer of M2UA and M3UA.

M2UA and M3UA are used as the IP adaptation layers of MTP2

and MTP3 respectively, and are used for interworking between

SCN and IP network. The upper layer user of M2UA is MTP3 and

the further upper layer user is ISUP, while the very upper layer

user of M3UA is ISUP directly. MTP2 needs no signaling point

while MTP3 must have its own signaling points.


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