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The hitchhiker guide is a map

RFC 5411 is an informational map of the SIP document set, and it does not replace the base specification.

Learn in 5 minutes

  1. Use RFC 5411 as an index
  2. Open the specific RFC that defines a header
  3. Notice that later RFCs are outside that snapshot

Visual

The map names the document · study drawing · cyphermonkeylabs.com AliceSBCBob INVITE 100 INVITE 180 180 200 200 ACK

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Start at the map when you do not know which RFC owns a header. Finish in the RFC that defines it.

Worked example

Name the document On the 180, decide which RFC you would open if the response also contained Require: 100rel.

  1. Step to the 180.
  2. Inspect it and note that 100rel is absent.
  3. Name the RFC you would open if Require: 100rel were present.

Fault

A design cites only RFC 5411 for the ACK of a 200 OK and then retransmits that ACK on a timer copied from INVITE.

5411 does not define the transaction timers. Timer A retransmits the INVITE on UDP, not a 2xx ACK.

Quiz

RFC 5411 is


PRACK is defined in


When 5411 and a later RFC disagree


UPDATE is defined in


The base INVITE rules remain in


A header missing from RFC 3261 section 20 usually means


Ecosystem

Glossary, sister systems, and the integration seam for this room.

CRM Screen pop uses data the contact center already has: ANI, DNIS, case id. Those values may arrive in SIP headers or in a CTI event after the call is up. The CRM is not a SIP element.

Glossary · Ecosystem map · Ports · Troubleshooting

Sources and go deeper