ICMP latency jumps every 60 seconds ?!?

[FilthyMinx]

Hi all,

I wonder if anyone's ever seen this. If I do an extended ping from the router, say 100000 packets , everything goes just fine for a bit and then suddenly slows up drastically. It then picks up OK but almost exactly 65 seconds later the problem recurrs ??!

Sitting with a stop watch I can predict the start of this behaviour to the second time and time again.

So far I'm drawing blanks trying to figure out why this is happening - anyone got any ideas ?

TIA !!

 

[svermill]

Routing protocol updates? Something along those lines?

 

[tcvander]

Are you running IPX? and or you running RIP for IP?

Both of these have a default timer of 60 seconds for updates. Todd VanDerwerken, CCNA, CCDA
Technical Consultant

http://www.ciscolinks.net

"If at first you don't succeed...then sky diving isn't for you!"

 

[svermill]

As is SAP I believe....

 

[tcvander]

Correct, IPX RIP/SAP updates are every 60 seconds. The number and size of the updates can sometimes bring a network to it's knees. Todd VanDerwerken, CCNA, CCDA
Technical Consultant

http://www.ciscolinks.net

"If at first you don't succeed...then sky diving isn't for you!"

 

[svermill]

Or at least slow things down a bit. I understand that a Cisco device places very low priority on ICMP packets generated by the device itself. So, if pinging from the router while it has better things to do (updates, etc), some latency might be observed. On the other hand, I understand that Cisco devices place a very high priority on "pass-through" ICMP. The results might change if he were to ping from an attached machine vs. the router itself.