[Last Call] Learn about multicloud storage options and how to improve your company's cloud strategy. Register Now

x
?
Solved

Cisco switch not acting right

Posted on 2013-01-17
10
Medium Priority
?
623 Views
Last Modified: 2013-01-17
On a new install of a WS-C2960S-48TS-L.  The switch has 4 SFP ports.  I have other Cisco switches with the same SFP port module this one has and am fimiliar with them.  The documentation claims I am using the correct SFP module.  

I installed a new GLC-SX-MM module in one of the ports and connected it to a SFP port on my WS-C2960G-24TC-L.  Here is what happens:

C2960S (new) - Gi1/0/50 1000 BaseSX SFP Status: Port is disabled.

C2960G  (existing) - Gi0/23 1000 Base SX SFP Status: Link up  Speed 1000 mbps  Duplex Full.

I can't find any way to get it to work.  I have disabled and enabled the port without luck. I have used different SFP modules in different ports.  Same result.

Is the switch defective?
0
Comment
Question by:skkinney
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 4
  • 2
10 Comments
 
LVL 11

Expert Comment

by:rharland2009
ID: 38788773
It sounds remarkably like the port is blocking.
Do a sh spanning-tree blockedports while the interface in question is connected.
Do a sh spanning-tree gi1/0/50 as well.
0
 

Author Comment

by:skkinney
ID: 38788834
CS-G-830-1>sh spanning-tree

VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32768
             Address     0009.5bb3.c8c9
             Cost        20004
             Port        1 (GigabitEthernet1/0/1)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     5897.1ea7.5000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------
Gi1/0/1             Root FWD 4         128.1    P2p
Gi1/0/8             Desg FWD 4         128.8    P2p
Gi1/0/14            Desg FWD 4         128.14   P2p
Gi1/0/30            Desg FWD 4         128.30   P2p
Gi1/0/33            Desg FWD 4         128.33   P2p
Gi1/0/34            Desg FWD 4         128.34   P2p
Gi1/0/35            Desg FWD 4         128.35   P2p
Gi1/0/47            Desg FWD 4         128.47   P2p
Gi1/0/48            Desg FWD 4         128.48   P2p
Gi1/0/50            Altn BLK 4         128.50   P2p
0
 
LVL 11

Expert Comment

by:rharland2009
ID: 38788867
It's blocking - BLK tells us that.
Before you unblock it, find out why it's doing this - and by that I mean find out what loop you're being protected from by spanning-tree.
If you want redundant links, etc. I would suggest configuring the links as Etherchannel.
0
NEW Veeam Agent for Microsoft Windows

Backup and recover physical and cloud-based servers and workstations, as well as endpoint devices that belong to remote users. Avoid downtime and data loss quickly and easily for Windows-based physical or public cloud-based workloads!

 

Author Comment

by:skkinney
ID: 38788938
So you are saying it is protecting itself, probably from loopback?  I have no other direct connections to the other switch.  There is a third switch involved that provides an indirect link.  Could this be the problem?

How do I unblock it?
0
 
LVL 50

Accepted Solution

by:
Don Johnston earned 2000 total points
ID: 38789056
How do I unblock it?
You could unplug the G1/0/1 port. It's blocking G1/0/50 because there's another path to the root.  Spanning-tree has determined that the best path to the root is out the G1/0/1 port.
0
 

Author Comment

by:skkinney
ID: 38789066
OK, so that confirms the third switch is the problem.  Thanks for your help.
0
 
LVL 11

Expert Comment

by:rharland2009
ID: 38789095
You're welco-oh wait, you weren't thanking me....guess I gave you zero info that helped. Good times!
0
 
LVL 50

Expert Comment

by:Don Johnston
ID: 38789114
Yeah... These points should go to rharland2009.
0
 

Author Comment

by:skkinney
ID: 38789124
Oh, I am so sorry.  I wasn't paying attention.  How do we get the points to the correct person?
0
 
LVL 11

Expert Comment

by:rharland2009
ID: 38789142
Don't sweat it...I was just being snarky. Glad you got your gear rockin.
0

Featured Post

Tech or Treat! - Giveaway

Submit an article about your scariest tech experience—and the solution—and you’ll be automatically entered to win one of 4 fantastic tech gadgets.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This tutorial will go through the steps required to write a script that will back up the configuration settings of a HP-ProCurve switch. You will need to get the following things to follow this tutorial: Telnet Scripting Tool e.g. TST10.exe …
Arrow Electronics was searching for a KVM  (Keyboard/Video/Mouse) switch that could display on one single monitor the current status of all units being tested on the rack.
This course is ideal for IT System Administrators working with VMware vSphere and its associated products in their company infrastructure. This course teaches you how to install and maintain this virtualization technology to store data, prevent vuln…
This tutorial will teach you the special effect of super speed similar to the fictional character Wally West aka "The Flash" After Shake : http://www.videocopilot.net/presets/after_shake/ All lightning effects with instructions : http://www.mediaf…
Suggested Courses

650 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question