About Sctp

7/31/2019 About Sctp

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About SCTP

Bersifat Connection-oriented

Merupakan inti dari sigtrans

Menyediakan layanan lapisan transport over IP Merupakan suatu layer yang terletak antara layer user

adaptation dan layer IP di dalam protokol Sigtran.

Layer ini dirancang untuk menyediakan aplikasi

protokol transmisi


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SCTP User Application

SCTP Transport Service

IP Network Service

Asso

ciationstar

upand

takedown

Sequence dilivery within

stream

User Data Fragmentation

Acknowledgement and

Congestion Avoidance

Chunk Bundling

Packetv Validation

Path Management


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Sekilas Proses Aliran Data Dalam

Protokol SCTP


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Header

MAC Add IP Add SCTP Packet Header

Source Dest Source Dest S.Port D. Port Tag CRC Payload

Chunk Chunk

Type Length TSN SI SSN Data Type Length TSN SI SSN Data

SCTP Data Chunks

Format of an SCTP Datagram

Reference : RFC 2960


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SCTP Control Chunk


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SCTP Paket Chunk


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Chunk Types

ID Value Chunk Type ----- ---------- 0 - Payload Data (DATA) 1 - Initiation (INIT) 2 - Initiation Acknowledgement (INIT ACK) 3- Selective Acknowledgement (SACK) 4 - Heartbeat Request (HEARTBEAT) 5 - Heartbeat Acknowledgement (HEARTBEAT ACK) 6 -Abort (ABORT) 7 - Shutdown (SHUTDOWN) 8 - Shutdown Acknowledgement (SHUTDOWN ACK) 9 - Operation Error (ERROR) 10- State Cookie (COOKIE ECHO) 11 - Cookie Acknowledgement (COOKIE ACK) 12 - Reserved for Explicit Congestion Notification Echo (ECNE)13 - Reserved for Congestion Window Reduced (CWR) 14 - Shutdown Complete (SHUTDOWN COMPLETE)

15 to 62 - reserved by IETF

63 - IETF-defined Chunk Extensions





192 to 254 - reserved by IETF 255 - IETF-defined Chunk Extensions

00 - Stop processing this SCTP packet and discard it, do not process

any further chunks within it.

01 - Stop processing this SCTP packet and discard it, do not process

any further chunks within it, and report the unrecognized

parameter in an 'Unrecognized Parameter Type' (in either an

ERROR or in the INIT ACK).

10 - Skip this chunk and continue processing.

11 - Skip this chunk and continue processing, but report in an ERROR


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Chunk flag:

Chunk Length

Chunk Value: variable length


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SCTP Chunk Definitions

A. Initiation (INIT)

This chunk is used to initiate a SCTP association between

two endpoints. The format of the INIT chunk is shown

below:


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B. Initiation Acknowledgement (INIT ACK)

The INIT ACK chunk is used to acknowledge

the initiation of an SCTP association. The

parameter part of INIT ACK is formatted

similarly to the INIT chunk. It uses two extra

variable parameters: The State Cookie and

the Unrecognized Parameter: The format ofthe INIT ACK chunk is shown below:


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Cookie

When sending an INIT ACK as a response toan INIT chunk, the sender of INIT ACK creates aState Cookie and sends it in the State Cookie

parameter of the INIT ACK. Inside this StateCookie, the sender should include a MAC (see[RFC2104] for an example), a time stamp onwhen the State Cookie is created, and the

lifespan of the State Cookie, along with all theinformation necessary for it to establish theassociation.


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Cookie Echo (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. This chunk MUST

precede any DATA chunk sent within the

association, but MAY be bundled with one or

more DATA chunks in the same packet.


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Cookie Acknowledgement (COOKIE

ACK)


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INIT : INIT (Initiation) adalah chunk pertama yang dikirim oleh connecting host, INIT digunakan untukmemulai hub baru dgn host tujuan

4-Way Handshake

INIT-ACK : Respon ACK untuk INIT (Initiation) yang pertama dikirim oleh connecting host

COOKIE-ECHO : Dikirimkan oleh inisiator untuk melengkapi proses handshake, Cookie-Echo ini harumengawali semua data tap bisa juga dikirimkan berbarengan pada kiriman pertama

About Sctp

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