What are TCP proxy engines? What are TCP flow engines?
In which RFCs are they described? On Mon, 2 Aug 2021, 02:47 Vasilenko Eduard, <[email protected]> wrote: > Hi Alexander, > > > > Have I understood your presentation right? > > The client SHOULD change IPv6 flow label after SYN RTO to have a chance to > be moved to the working path inside DC fabric (if DC fabric supports flow > label for hash calculation) > > But at the same time > > The client SHOULD NOT change the IPv6 flow label after SYN RTO to avoid > being switched to a different TCP proxy engine. > > > > Looks like a deadlock, especially if both things should happen for the > same traffic: > > it should reach DC fabric > > and > > it should be hash load-balanced between different TCP proxy engines (or > applications) inside DC Fabric. > > > > I see one bad solution (“Disable Flow Label”): > > Routers up to TCP proxy engine SHOULD be configured not to use flow label > (by the way these are all routers on the Internet), > > TCP flow engines SHOULD be outside of the DC Fabric (CLOS) – probably in > front of it. > > Routers/Switches inside DC Fabric SHOULD use flow labels. > > > > I see another bad solution (“Disable Anycast”): > > Disable anycast on routers in principle, use only stateful LB. > > > > > > It has been commented in the chat that Anycast is not possible in > principle for stateful connection. It is too general a statement. > > Anycast is just not compatible with Flow Label. It is not a problem for > IPv4 anycast even if the connection is stateful (TCP) because 5-tuple for > hash would not change. > > Hence, IPv6 anycast has become dead at the time when Flow Label change has > been added in LINUX for active TCP session. > > > > Among 3 thins: > > - Anycast > > - Flow Label load balancing (basic Flow Label functionality) > > - Flow Label change on the active session for application to be > more active in new path search > > You have to choose which one to kill – all 3 are not compatible with each > other at the same. > > I vote to disable Flow Label change in LINUX. Then wait till the network > would fix itself. > > We have so many fancy TE tools our days. A broken link or a broken node > could be excluded from routing for 50ms. > > > > PS: I am not subscribed to the RTGWG alias, please keep me on a copy of > this thread. > > [image: cid:[email protected]] > > Best Regards > > Eduard Vasilenko > > Senior Architect > > Europe Standardization & Industry Development Department > > Tel: +7(985) 910-1105, +7(916) 800-5506 > > > _______________________________________________ > rtgwg mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/rtgwg >
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