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.
[cid:[email protected]]
Best Regards
Eduard Vasilenko
Senior Architect
Europe Standardization & Industry Development Department
Tel: +7(985) 910-1105, +7(916) 800-5506
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