[c-nsp] Weird ARP Issue with 3rd party equipment

[Paul Stewart]

Hi folks..

 

We've had an ongoing issue for a while involving ARP timeouts - we're pretty
confident it's a 3rd party hardware issue but wanted to solicit some
feedback please...

 

2 X Cisco 3825 and a Cisco 1841 so far have been identified - all three of
these routers have different software loads on them.

 

All of these routers connect to a Motorola CMM module which in turn connects
to 6 Motorola Access Points which in turn have dozens of Motorola subscriber
units connected.

 

The CMM module and the Access Points never have an issue - the subscriber
units have the problem of being reachable/pingable.  When they are not
reachable, the web interface doesn't work neither.  All of the Motorola
equipment involved are identical units with same software revisions.

 

Here's an actual example from one of the sites (Cisco 3825 running 12.4.17a)
:

 

dis1-rtr-cv#ping 10.254.253.49

 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.254.253.49, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

 

dis1-rtr-cv#sh arp | inc 10.254.253.49

Internet  10.254.253.49         107   0a00.3e24.aa0b  ARPA   Vlan10

 

No matter how many pings it will not respond - however - if we clear the ARP
table manually it becomes reachable after it "wakes up":

 

dis1-rtr-cv#clear arp

dis1-rtr-cv#sh arp | inc 10.254.253.49

dis1-rtr-cv#ping 10.254.253.49

 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.254.253.49, timeout is 2 seconds:

.!!!!

Success rate is 80 percent (4/5), round-trip min/avg/max = 4/8/12 ms

dis1-rtr-cv#sh arp | inc 10.254.253.49

Internet  10.254.253.49           0   0a00.3e24.aa0b  ARPA   Vlan10

 

 

The part that is very puzzling for us and for Motorola is that we have 30+
other sites with 1800/2600/2800/3800 series routers running various IOS
releases connected in the same fashion to the same Motorola equipment all
running the same software release and don't experience this issue.  I'm
trying to figure out what makes these sites "special"?

 

Thanks for any input,

 

Paul