Mailing List Archive: [nsp] router-switch port speed negotiation

[nsp] router-switch port speed negotiation

Aug 24, 2002, 8:27 AM

Post #1 of 4 (2364 views)

Hi
I have cisco router(2600) and switch (2950)

Now I am connecting router's ethernet port in switch.

But I seen in the show int fastethernet on switch, showing me half
duplex and 10 mbps,

and all other ports are working on 100/full .

All the ports on switch and router are in Auto mode.

Than why the port connected to router is not working on 100/full and
working on 10/half????

Any clue.

Thanks
--pakucable

Re: [nsp] router-switch port speed negotiation [ In reply to ]

ssprunk at cisco

Aug 24, 2002, 1:05 PM

Post #2 of 4 (2302 views)

Permalink

Thus sapke "pakucable" <pakucable@nettaxi.com>
> I have cisco router(2600) and switch (2950)
>
> Now I am connecting router's ethernet port in switch.
>
> But I seen in the show int fastethernet on switch, showing me half
> duplex and 10 mbps,
>
> and all other ports are working on 100/full .
>
> All the ports on switch and router are in Auto mode.
>
> Than why the port connected to router is not working on 100/full and
> working on 10/half????
>
> Any clue.

2600's do not auto-negotiate. You must hard-code both sides.

S

Re: [nsp] router-switch port speed negotiation [ In reply to ]

jlewis at lewis

Aug 24, 2002, 9:10 PM

Post #3 of 4 (2312 views)

Permalink

On Sat, 24 Aug 2002, Stephen Sprunk wrote:

> 2600's do not auto-negotiate. You must hard-code both sides.

Don't do it well, or don't do it at all??

cisco 2620 (MPC860) processor (revision 0x102) with 53248K/12288K bytes of
memory.

FastEthernet0/0 is up, line protocol is up
Hardware is AmdFE, address is 0002.fd39.2fc0 (bia 0002.fd39.2fc0)
Internet address is xxxxxxxxxxxx
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, 100BaseTX/FX

interface FastEthernet0/0
ip address xxxxxxxxxxxx
duplex auto
speed auto

----------------------------------------------------------------------
Jon Lewis *jlewis@lewis.org*| I route
System Administrator | therefore you are
Atlantic Net |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________

Re: [nsp] router-switch port speed negotiation [ In reply to ]

james+cisco at vincentsystems

Aug 25, 2002, 9:18 PM

Post #4 of 4 (2310 views)

Permalink

On Sun, Aug 25, 2002 at 12:10:45AM -0400, jlewis@lewis.org wrote:
|
| Don't do it well, or don't do it at all??

It doesn't do it well. Speed is (usually) negotiated properly, but duplex
usually isn't. Do a "show controller fast 0/0" and look for a line
starting with "BCR9". If it says half-duplex, but "show interface" says
full (as below), you need to force full duplex.

| Full-duplex, 100Mb/s, 100BaseTX/FX

In my experience, output from "show interface" is wrong. I've also noted
that the full-duplex LED on the back never lights up. I'm on 12.0(7)T,
and have seen this behavior against Cisco 3500XL and HP 4000M switches.

-James