Grenville Armitage and Gorry Fairhurst TCPM WG - IETF 94, Yokohama 5 - PowerPoint PPT Presentation

Update on TCP Alterna0ve Backoff with ECN (ABE) dra=-khademi-alterna0vebackoff-ecn Naeem Khademi, Michael Welzl, Grenville Armitage and Gorry Fairhurst TCPM WG - IETF 94, Yokohama – 5 November 2015

I-D’s Scope An experimental update to RFC3168: updates the TCP sender-side • reacMon to a congesMon noMficaMon received via ECN RFC3168 Sec0on 6.1.2: • “If the sender receives an ECN-Echo (ECE) ACK packet…the indicaMon of congesMon should be treated just as a conges0on loss in non-ECN-Capable TCP. That is, the TCP source halves the congesMon window cwnd and reduces the slow start threshold ssthresh .” Update to RFC3168 Sec0on 6.1.2: • “If the sender receives an ECN-Echo (ECE) ACK packet…the indicaMon of congesMon SHOULD induce a less conserva0ve reac0on than loss: the TCP source mulMplies the congesMon window cwnd with 0.8 and reduces the slow start threshold ssthresh .” 2

Status of the I-D Discussions on the TCPM ML (up to IETF Prague): • – Addressed Mark Allman’s comments with regards to beta ecn as a percentage – Review from Anil Agarwal is responded Discussions on the ICCRG ML (a=er IETF Prague): • – Responded to comments from Michael Scharf and Bob Briscoe SubmiXed -01: • – Some editorial work, more elaboraMve text on the raMonale behind ABE in IntroducMon (SecMon 1) and Discussion (SecMon 2) – Discussion (SecMon 2) explains: • where ABE can be useful (lightly mulMplexed, high-BDP access links) • ABE is prac,cal rather than ideal (staMc beta rather than an adapMve one) • The choice of mulMplier (no change to beta loss ) – should -> SHOULD in the update of RFC3168 (SecMon 3) – The proposed update is “experimental” rather than standard-track 3

Q&A 4