[NANOG] Comcast latency

Tim Thompson tbt at ycrdi.com
Fri May 2 12:53:29 UTC 2008


> Tim Thompson wrote:
>> Here, in New England, I normally see 20% packet loss between Comcast
>> and Level3 in NewYork using MTR. It has been as high as 60% in the
>> past so this is an improvement.
>>
James Michael Keller wrote:
> Remember that a number of ISP's 'core' routers are going to have ICMP 
> rate limits in place when one of their interfaces is the target.   While 
> you may see high packet loss across an ISP link, unless you are getting 
> similar numbers from all hops past that point you aren't looking at real 
> packet loss, since the transit packets are getting through fine.  It's 
> just the routers themselves that are ignoring requests or discarding 
> responses in favor of pushing routed packets.

Yes, the routers after Level3's edge router don't show similar packet 
loss, so this must be the edge router just de-prioritizing ICMP. Thank 
you for pointing out my mistake.

-Tim




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