nanog mailing list archives

Re: Comcast Ethernet Feed


From: Brielle Bruns <bruns () 2mbit com>
Date: Thu, 29 Mar 2012 18:47:11 -0600

On 3/29/12 6:36 PM, Brian R. Watters wrote:
We are about to accept a 20MEG Ethernet feed via Comcast and their
fiber plant as well as a BGP feed across the same link.

I have a space GIGE interface on a 7206VXR and would like to know
best practice for deploying for optimal performance across this
interface.

Any ideas and or direction would be extremely helpful as we are
seeing some real issues such as.

Direct connect (without BGP) to the CPE from Comcast (Fiber to
Ethernet) via a laptop gives the level of performance we would
expect, However as soon as we terminate to our router via the GIGE
which is set to 100MB full duplex and all flow control turned off
(Negotiation auto) per Comcast and connect up via a 100MB fast
Ethernet interface directly connected we get a fraction of the speed
when direct connected.



From my own experience here with our 7200s, some of the PA based 100BaseT interfaces (ie: not on the IO module) can not negotiate 100-full, but rather only half. This leaves one end diff then the other and creates issues with performance. Try forcing both the laptop and router to 100-full and see if it helps.


--
Brielle Bruns
The Summit Open Source Development Group
http://www.sosdg.org    /     http://www.ahbl.org


Current thread: