RE: [PATCH v4 net-next 0/2] ipv4: Hash-based multipath routing

From: Peter Nørlund

Sent: 29 September 2015 12:29

...

As for using L4 hashing with anycast, CloudFlare apparently does L4
hashing - they could have disabled it, but they didn't. Besides,
analysis of my own load balancers showed that only one in every
500,000,000 packets is fragmented. And even if I hit a fragmented
packet, it is only a problem if the packet hits the wrong load
balancer, and if that load balancer haven't been updated with the state
from another load balancer (that is, one of the very first packets). It
is still a possible scenario though - especially with large HTTP
cookies or file uploads. But apparently it is a common problem that IP
fragments gets dropped on the Internet, so I suspect that ECMP+Anycast
sites are just part of the pool of problematic sites for people with
fragments.

Fragmentation is usually more of an issue with UDP than TCP.
Some SIP messages can get fragmented...

	David