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

[Alex]

Paul,
I'd check a couple of things more:
1/ Are the pings actually being sent?
2/ if yes which physical interface the pings go out of? Can you sniff the 
wire?
Rgds
Alex

--------------------------------------------------
From: "Paul Stewart" <paul at paulstewart.org>
Date: 29 December 2009 16:12
To: "'Cisco-nsp'" <cisco-nsp at puck.nether.net>
Subject: [c-nsp] Weird ARP Issue with 3rd party equipment

> 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
>
>
>
>
>
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