1. 1 IPFIX Default Transport IPFIX IETF-58 November 10, 2003 Stewart Bryant Benoit Claise

2. 222 IPFIX Transport IETF-58 The Issue IPFIX needs to specify a default, TCP friendly transport protocol. TCP friendly IETF transports defined, or in late stages of specification are: TCP, SCTP, PR-SCTP and DCCP. Some members of the WG propose that we standardise on TCP because it is ubiquitous. Other members of the WG propose that we standardise on PR-SCTP because its greater range of functionality better addresses the spectrum of IPFIX needs.

3. 333 IPFIX Transport IETF-58 Why SCTP + PR-SCTP Architecturally it’s the right protocol for the job.

4. 444 IPFIX Transport IETF-58 Best Fit to Architecture. SCTP with the PR-SCTP extensions Delivers reliable information just as TCP does. During uncongested periods, all the records marked for deletion under congestion will be reliably delivered. During congested periods, the sender will begin to drop packets to protect the network. PR-SCTP therefore offers all the advantages of TCP together with much of the flexibility of UDP, and is at all times TCP-friendly.

5. 555 IPFIX Transport IETF-58 PR-SCTP Flexibility PR-SCTP allows the IPFIX application the flexibility to use reliable, partially reliable and unreliable, over one association with multiple streams. For example some Options Template reporting and some metering info might use the reliable stream while the Data Records would use the partially reliable stream.

6. 666 IPFIX Transport IETF-58 Availability promotes use Choosing PR-SCTP as the default protocol means that PR-SCTP will be available to all exporters and collectors. quicker failover multihoming These would otherwise have to be constructed at applications level.

7. 777 IPFIX Transport IETF-58 PR-SCTP availability "PR-SCTP is not deployed widely enough to be considered a default for any IETF technology." There are about 20 implementations for SCTP. PR-SCTP is an extension of SCTP which is available. PR-SCTP may not yet be there in all of the implementations, but that is not a problem either since if you don't have PR-SCTP then you end up with basic SCTP with full reliability, which is no different than TCP.

8. 888 IPFIX Transport IETF-58 We need a Transport with an RFC "The default transport for a standards track protocol should at least be an RFC. " RFC PR-SCTP finished TSVWG last call quite some time ago, and will go to IESG last call as soon as the AD review phase is complete. This will happen shortly. PR-SCTP will be an RFC long before IPFIX.

9. 999 IPFIX Transport IETF-58 Weaning the Internet off UDP Ultimately the IPFIX RFC is only a guide. The customer will specify the system they need for their business, and vendors will build them. UDP is available today for export and demand for this is likely to continue. UDP is a very low overhead protocol and is available on ALL platforms under consideration. The IETF needs to migrate users away from UDP and SCTP better provides better prospect for this than TCP.

10. 10 IPFIX Transport IETF-58 Availability Assertion: "SCTP is not widely implemented" SCTP is available on: HP-UX Solaris Linux BSD Windows

11. 11 IPFIX Transport IETF-58 Why not TCP? TCP has a single mode - reliable congestion aware. Partial reliability has to be synthesised in the application. By the time you have the code to do this synthesis, you have implemented an inferior version of SCTP in the application.