Is there anything special about the address that the switch is ARPing for?
Is it the switch that is ARPing (from its management address) or is it something on the switch that is ARPing? If it is the switch itself, does it have its default gateway set up? I don't know the behavior of your non-Cisco switch, but I can imagine that if its default gateway was not configured, or if it was configured with its own management address as gateway, then it might ARP on all VLANs. Especially if it does not attach its management functions to any particular VLAN.
I dn't understand what you are asking. Over 1,000 is a lot of VLANs. You also suggest hosts configured with /32 masks. Is this one vlan per host? What type of router is the PE and how is it configured.
I hav a suspicion that the VPLS-PE router may just be bridging all the VLANs together. I must admit to no familiarity with VPLS though, my knowledge can be summed up as "it looks like LANE for MPLS"
I was more asking if you could add at least a part of the config.
The trick with troubleshooting it to at least at a top level work out what could cause a problem and check it.
In this case, you have ARPs goig to a number of VLANs. The two obvious causes are that something is bridging across VLANs or the device generating the ARP is sending it to multiple VLANs. So we need to check if it is either of those.
What does a debug ip arp tell you on the PE?
I note you added an extract of the config that suggested that adress should be routed to nu0 - if that is correct, the router should not be arping at all. It might be worth a sh ip ro a.b.c.205 to see if there is a more specific route that beats that comparatively wide route.
That is a bit of the "is it sending to multiple VLANs?" next is "is there something bridging?" a look at the local config would help, but this may be the more challenging one to look at, as bridging may not be hapenning locally. I assume the 0017.0fa6.dc1b address is an address associated with the PE? it may be worth looking if you can sniff the MPLS side of the PE, just to see if the PE is sending into the cloud, and something elsewhere is bridging. Is any other traffic being replicated across the VLANS?
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...