nanog mailing list archives

Re: Comcast Ethernet Feed


From: Randy <randy_94108 () yahoo com>
Date: Thu, 29 Mar 2012 19:32:58 -0700 (PDT)

Never mind control and what Comcast says about hard-coding speed and duplex!
The question is:

What happens when you set the int facing Comcast CPE to auto?
Does the link even come up?
*IF* the link comes up, can you ping your next-hop?

If you can, leave auto-neg on despite what what Comcast may say/require.

Post a "sh int gix/y" and "sh int fax/y"

If the above outputs are *clean*, I would say a TAC case is called for.


--- On Thu, 3/29/12, Brian R. Watters <brwatters () absfoc com> wrote:

From: Brian R. Watters <brwatters () absfoc com>
Subject: Re: Comcast Ethernet Feed
To: "Randy" <randy_94108 () yahoo com>
Cc: "NANOG list" <nanog () nanog org>
Date: Thursday, March 29, 2012, 7:02 PM


A couple of questions - 

1) What flavor of NPE are you using?

NPE-G1

2) Is the GigE interface on the NPE-G1/G2  OR is this a
PA?
3) Is the FaE ethernet interface that you appear to be
connecting your laptop to, on a separate PA in chassis?

Laptop connected directly to router via slot 4 
PA-FE-TX

4) Have you verified you that "bandwidth-points" have not
been exceeded for bus-1 and/or 2: slots 1,3,5 for bus1 and
2,4,6; also 0(if I/O controller is present. It is 600 points
for bus1 and 600 for bus2.

PCI bus mb1 has 390 bandwidth points
PCI bus mb2 has 500 bandwidth points


Have you *hard-coded* speed and duplex on any of you eth
ints? Please don't!

GIGE has been both hard and auto .. same results .. Fast
Ether has always been set @ auto

Let both ints auto-negotiate speed&duplex.

Comcast states that we are required to have a hard code FULL
DUPLEX and SPEED 100 as well as flow control OFF however I
can not appear to be able to disable it :(


after having done so, post the output of:

sh int gi x/y and sh int fa x/y

(hardcoding speed/duplex is sometimes required when dealing
with brain-dead CPE. I have also seen other flavors of
brain-dead CPE that *only* work when speed/duplex are set to
auto)

./Randy




Current thread: