[f-nsp] ARP and VRRP-E on FastIron

[frnkblk at iname.com]

We turned up a feature on an access shelf downstream of our Brocade ICX6650
stack that broke most end-user connectivity. 

We're using VRRP-E, with x.y.z.2 and x.y.z.3 as physical IPs on routers A
and B, respectively, and x.y.z.1 as the virtual IP.

After our vendor did some troubleshooting they shared that while the devices
downstream of the access shelf were ARPing for the virtual IP of .1, ICX
6650 "B" was responding to the ARP with a source IP address of .3, and the
access shelf would (properly) discard it (it appears spoofed, of course).

We hope to get packet capture overnight, but while that's in process, does
anyone have insight into how it should and does work?

According to the documentation
(http://www.brocade.com/content/html/en/configuration-guide/fastiron-08030b-
l3guide/GUID-5E2D993A-C30C-4998-A98E-5B75731A2BA1.html), "When an ARP
request packet for the virtual router IP address is received by the Backup
router, it is forwarded to the Master router to resolve the ARP request.
Only the Master router answers the ARP request for the virtual router IP
address."  That doesn't make it clear if the Master router (in our case, A),
uses it's physical or virtual IP.

Frank