[f-nsp] ALB + VRRP

[Nick Morrison]

Hi,

Has anyone got any first-hand experience with servers running ALB (adaptive
load balancing is what Linux calls it - windows machines know it by other
names, maybe "active active" load sharing - where the host is connected
with multiple NICs to multiple edge switches (same segment), and
round-robins its ARP replies so that different hosts on the same segment
know the single IP by different MACs) ... in conjunction with RX routers
running VRRP-E?

I'd like to hear about your experiences.  I'm having a few issues that look
like our two VRRP-E RX routers are trying to be smarter than I want them to
be (ARP snooping, but buggering it up so that their ARP table ports don't
match their MAC table ports, and so sending traffic destined to one of the
NICs on the server out of the wrong port) but it's hard to pinpoint the
cause of the problem...

Topology is two edge RX-8s, cross-connected to two distribution RX-8s.
Edge RX-8s just do L2, distro RX-8s hold the default gateway and do VRRP-E.
Host is connected to both edge RX-8s.  One IP address, two MAC addresses
(one per NIC), same VLAN, both NICs up and active, host manages ARP replies
carefully.  (In theory.)


Cheers,

Nick!