slowing down every 60 seconds due to BGP scaner

Fri Sep 14 21:11:00 UTC 2001

Jesper Skriver wrote:

> ping's to the router will show this, and cannot be used for anything,
> what about end to end traffic ?

"David McGaugh" <david_mcgaugh at eli.net> writes:

> We've brought this concern up to Cisco before and they assured us that
> everything is performing normally. You will see this when performing
> router to router pings as well however, we have been told that packet
> forwarding does not suffer. ICMP replies from the router (not through
> the router) are given a very low CPU priority.

"Robert E. Seastrom" wrote:

> Seconded.  Ping response times or lack of ping response from routers
> signifies *nothing*.  Ditto for traceroutes, &c.  Ping *through* the
> router, not *to* the router.

I think we're all in agreement here. Here's what I said Tang after he 
said what his platform was. The original message didn't have that info, 
so I sent several possibilities - all off channel. Wasn't on nanog-post
at the time (which is why the larger group was not CC'd).

-------- Original Message --------
Subject: Re: slowing down every 60 seconds due to BGP scaner
Date: Fri, 14 Sep 2001 12:13:46 -0700
From: Chris Konger <ckonger at internap.com>
To: tang bing <tang_bing at yahoo.com>

tang bing wrote:

> We will put more memory and enable CEF on the line cards 
> to see if its better .

If the customer is doing the test from their *router*, the lags
are due to the pings being process-switched and thus impacted by
the correlated bgp-scanner.

The best test is to ping *through* the routers via other src/
dst boxen (some servers hanging off the routers). That way the
'pings from the routers always being process-switched' won't
be impacted. Alternatively, you can ping for a long long time
and the 60 second spikes will wash out in the average (but will
still show up in the max value).

Hope this helps!

CK

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