[c-nsp] Cisco gig ethernet config question

Todd, Douglas M. DTODD at PARTNERS.ORG
Fri Dec 17 09:16:01 EST 2004 

Rob:

Do a sh counters int gig5/1 and see if you have any errors etc.  If you are a
short distance 100M or so then you should use SX and not LX gbic unless you are
using an attenuator on one of the ends to bring the powerlevel down on the
sending/receiving gbic. I would also enable cdp on this link until you get the
testing complete (if possible), cdp is a good troubleshooting tool. 

See if you have any errors on the ports that is a good starter.

As for your configuration - 
I would change your trunk to the following (are you using vlan 1 for any
purpose?)
switchport trunk allowed vlan 100,240,500
Switchport nenegotiage add to your configs this will make the port trunk and not
try to negotiate a trunk.
I would also add the command udld enable to the global and then udld port
aggressive on both ends. This will detect unidirectional with your fiber.  If
you have one the port will go into error disabled. This will help diagnose bad
fiber.

What's the reason for changing the native vlan on the gig interface?  


interface GigabitEthernet5/1
switchport trunk encapsulation dot1q
switchport trunk native vlan 100
switchport trunk allowed vlan 1,240,500,1002-1005  
switchport mode trunk  
description MSPBES001P (Gi1/1)  
speed nonegotiate  
no snmp trap link-status  
no cdp enable


==DMT>

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Douglas M. Todd, Jr.
Network Engineering (MGH/CNY/NSMC/MCLEAN)
Partners Health Care
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old>>-----Original Message-----
old>>From: cisco-nsp-bounces at puck.nether.net 
old>>[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of 
old>>Robert Walton
old>>Sent: Thursday, December 16, 2004 20:00
old>>To: Church, Chuck; cisco-nsp at puck.nether.net
old>>Subject: RE: [c-nsp] Cisco gig ethernet config question
old>>
old>>cheers guys... it turns out our reseller installed one of 
old>>the switches with LX gbics instead of SX!!! 
old>>
old>>many thanks,
old>>Rob
old>>
old>>-----Original Message-----
old>>From: Church, Chuck [mailto:cchurch at netcogov.com]
old>>Sent: 16 December 2004 23:12
old>>To: Robert Walton; cisco-nsp at puck.nether.net
old>>Subject: RE: [c-nsp] Cisco gig ethernet config question
old>>
old>>
old>>Robert,
old>>
old>>	Couple possible config issues.  You're not allowing the 
old>>native VLAN.  Not sure what that would do.  Also, the 
old>>speed nonegotiate command doesn't seem needed.  GBICs only 
old>>do gigabit, no speed could ever be negotiated.  Away from 
old>>the config, are these singlemode GBICs?  It's possible 
old>>your fiber distance is too short and you're over-driving 
old>>the receiver.  When you loop it and it works, you've just 
old>>doubled the distance, possibly making it work.  Just a 
old>>couple ideas... 
old>>
old>>
old>>Chuck Church
old>>Lead Design Engineer
old>>CCIE #8776, MCNE, MCSE
old>>Netco Government Services - Design & Implementation Team 
old>>1210 N. Parker Rd.
old>>Greenville, SC 29609
old>>Home office: 864-335-9473
old>>Cell: 703-819-3495
old>>cchurch at netcogov.com
old>>PGP key: 
old>>http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x4371A48D 
old>>
old>>
old>>-----Original Message-----
old>>From: cisco-nsp-bounces at puck.nether.net
old>>[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of 
old>>Robert Walton
old>>Sent: Thursday, December 16, 2004 5:08 PM
old>>To: cisco-nsp at puck.nether.net
old>>Subject: [c-nsp] Cisco gig ethernet config question
old>>
old>>Hi,
old>>
old>>	Bit of a newbie question here but I've got two Gig E 
old>>switches directly connected with fibre - both catalyst 4006's.
old>>
old>>	When i put fibre loops on at each end of the link i can 
old>>bring the opposite gbic up but as soon as i terminated the 
old>>fibre pairs on the gbics i get nothing... and yes i've 
old>>tried switching the ends round.
old>>
old>>The config i have at both ends is as follows...
old>>
old>>interface GigabitEthernet5/1
old>> switchport trunk encapsulation dot1q
old>> switchport trunk native vlan 100
old>> switchport trunk allowed vlan 1,240,500,1002-1005  
old>>switchport mode trunk  description MSPBES001P (Gi1/1)  
old>>speed nonegotiate  no snmp trap link-status  no cdp enable
old>>
old>>any hints would be much appreciated... or example configs. ;o)
old>>
old>>cheers guys...
old>>Rob
old>>
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