08-06-2009 03:24 AM - edited 03-06-2019 07:07 AM
I can't find the doc anywhere to answer my question so I'm am hoping someone can help me out ;)
I have a 3750 set as a gateway router on one of the VLANs. From a host somewhere out there on the VLAN I send an ARP request for the gateway address which is the 3750. The ARP is received by the 3750 as a tagged packet with pbit=0. The 3750 sends an ARP reply as expected but the pbit=7.
My question is why is the ARP reply marked with pbit=7? I have my hunches as to why but I usually get into trouble when I assume.
I'd really appreciate the feedback.
Gayle
08-06-2009 04:52 AM
I tried to find a document on the Cisco website supporting this but I haven't found one, so my supposition is the following:
ARP replies originated by the Cisco devices are treated as Network Control frames, just like spanning-tree bpdus, therefore they are set with CoS=7.
Cheers:
Istvan
08-06-2009 04:55 AM
Thanks for the feedback. This is my theory too from some other experience I have.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide