1.0 SIGTRAN protocol Slide 2 Objectives SIGTRAN application in
R4 network SIGTRAN protocol structure and message introduction
SIGTRAN signaling flow Upon completion of this course,you will be
able to: Slide 3 Course Content Chap1 overview Chap2 SCTP protocol
Chap3 M3UA protocol introduction Chap4 SIGTRAN application Slide 4
SIGTRAN 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). Slide 5
Introduction of M3UA Slide 6 Course Content Chap1 overview Chap2
SCTP protocol Chap3 M3UA protocol introduction Chap4 SIGTRAN
application Slide 7 Chap2 SCTP protocol 1.1 overview 1.1 overview
1.2 SCTP terms 1.3 SCTP function 1.4 SCTP message structure Slide 8
SCTP 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. Slide 9 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. Slide 10 Chap2 SCTP protocol 1.1 overview
1.2 SCTP terms 1.2 SCTP terms 1.3 SCTP function 1.4 SCTP message
structure Slide 11 SCTP 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. Slide 12 Host 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. Slide 13 Association and stream Slide 14
TSN 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 stream of an SCTP
association, a 16-bit sequence number is assigned to each data
chunk sent in the stream by the local end, in order to ensure the
sequenced transmission in the stream. SSN is maintained on the
basis of stream. Slide 15 TSN 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. dataTSNSSN A11 B21 C32 D142 D252 Slide
16 CWND 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
recently calculated receiver window of its peer, in number of
bytes. Slide 17 Chap2 SCTP protocol 1.1 overview 1.2 SCTP terms 1.3
SCTP function 1.3 SCTP function 1.4 SCTP message structure Slide 18
SCTP 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. Slide 19 Chap2 SCTP
protocol 1.1 overview 1.2 SCTP terms 1.3 SCTP function 1.4 SCTP
message structure 1.4 SCTP message structure Slide 20 SCTP message
COMMON HEADER CHUNK Slide 21 SCTP message type Message
NameDescription DATAThe payload user data INITThis chunk is used to
initiate a SCTP association between two endpoints. INIT ACKThe 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
in the present association. HEARTBEAT ACKAn endpoint should send
this chunk to its peer endpoint as a response to a HEARTBEAT chunk.
ABORTThe ABORT chunk is sent to the peer of an association to close
the association. SHUTDOWNAn endpoint in an association MUST use
this chunk to initiate a graceful close of the association with its
peer. SHUTDOWN ACKThis chunk MUST be used to acknowledge the
receipt of the SHUTDOWN chunk at the completion of the shutdown
process. ERRORAn 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 ACKIt is used to acknowledge the
receipt of a COOKIE ECHO chunk. SHUTDOWN COMPLETEThis chunk is used
to acknowledge the receipt of the SHUTDOWN ACK chunk at the
completion of the shutdown process Slide 22 Startup 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 Slide 23 Termination 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. Slide 24 Course Content Training.huawei.com Chap1
overview Chap2 SCTP protocol Chap3 M3UA protocol introduction Chap4
SIGTRAN application Slide 25 Chap3 M3UA protocol introduction 3.1
overview 3.1 overview 3.2 basic concept 3.3 M3UA message structure
Slide 26 M3UA 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. Slide
27 M3UA protocol introduction SEP signal endpointSG signal
gatewayMGC media control Slide 28 M3UA protocol
introduction(continue) Slide 29 M3UA protocol introduction M3UA
also can be used to transfer signaling between two IPSP Slide 30
Chap3 M3UA protocol introduction 3.1 overview 3.2 basic concept 3.2
basic concept 3.3 M3UA message structure Slide 31 Basic 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.
Slide 32 Basic concept M3UA link state transition Slide 33 Basic
concept Relationship among M3UA Link, Linkset, Route and Entity
Slide 34 Basic concept M3UA route The path from source entity to
destination entity is called a M3UA route. One M3UA route
corresponds to one M3UA Linkset at the home terminal. Slide 35
Basic concept M3UA entity The logical processing unit that
accomplishes some special functions, such as AS, SP or a logic unit
that only implements special message transfer function, such as SG
can be classified as M3UA Entity. Each M3UA Entity is identified by
a unique signaling point code. M3UA LOCAL ENTITY: The logical
entity to accomplish special function in local side. M3UA
DESTINATION ENTITY: The logic entity to accomplish special function
in peer side. Slide 36 Chap3 M3UA protocol introduction 3.1
overview 3.2 basic concept 3.3 M3UA message structure Slide 37 M3UA
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. Slide 38 M3UA message introduction Management messages
Transfer messages SS7 Signaling Network Management messages ASP
State Maintenance messages ASP Traffic Maintenance messages Slide
39 Establishment procedure Slide 40 Data Transfer procedure
Determine the correct Destination Entity. If the destination Entity
is Accessible, then get the Available route 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 DATA 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 SGP, over the chosen
M3UA link. Slide 41 MTP_TRANSFER primitive handling at ASP Slide 42
MTP_TRANSFER handling at SGP Slide 43 Release procedure
