Solved

Cisco stacked 3750 switch

Posted on 2011-02-28
8
1,037 Views
Last Modified: 2012-05-11
Hi,

I have a stacked Cisco 3750 switch, two of them in this stack.  They have dual power to a Cisco 2200 redundant power unit.  It appears (according to tac) that the on board power unit on the second switch in the stack has failed, and the 2200 is what is keeping it up and running.  They told me the onboard power supply is not hotswappable, and the second switch in the stack must be replaced.  

What is the best way to do this ?  Do I shut down both switches, swap out the second switch, plug cables back in and power up ?  Do I just shutdown the second switch with the failed power supply, pop in the new one, plug in cables and power up ?  The cfg is on the first switch in the stack correct ?  Is there anything I need to pull off of the second switch ?

Thanks
0
Comment
Question by:Elemental12
[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
8 Comments
 
LVL 22

Expert Comment

by:eeRoot
ID: 35000143
If the switch with the failed power supply is NOT the stack master and is NOT the switch with the network uplink to the rest of the network, then you can replace it while leaving the primary switch up.  In a stack, the config is stored on all switches and synchronized automatically whenever there is a config change.  When the new switch powers up, it will inheret the config from the master switch.

Also, it would be a good practive to make sure that the new switch has the same firmeware version as the switch it's replacing.
0
 
LVL 32

Accepted Solution

by:
aleghart earned 333 total points
ID: 35000279
^ second that.  If the firmware levels do not match, you may end up with a brick.  The master may attempt replacing firmware.  If it is writing old over new...brick.  If it is writing new over old, but stalls/fails...brick.

Better to do the firmware upgrade offline, while the existing stack units are still functioning.
0
 

Author Comment

by:Elemental12
ID: 35000742
ewww ... Very nice thought guys, I did not even think of the firmware between the two.  I will add that to the list.  Dumb question, but what is the cmd to find out which one is the master ?

Thanks
0
IoT Devices - Fast, Cheap or Secure…Pick Two

The IoT market is growing at a rapid pace and manufacturers are under pressure to quickly provide new products. Can you be sure that your devices do what they're supposed to do, while still being secure?

 

Author Comment

by:Elemental12
ID: 35000882
show ver showed me :



Switch   Ports  Model              SW Version              SW Image
------   -----  -----              ----------              ----------
*    1   52     WS-C3750G-48TS     12.2(35)SE2             C3750-IPSERVICESK9-M
     2   52     WS-C3750G-48TS     12.2(35)SE2             C3750-IPSERVICESK9-M
 
So i assume the top switch is the master.  I am going to confirm by comparing ints plugged in (ie, if g0/1 in switch 1 is active, and g0/1 in switch 2 is inactive, and I go down there, and the top switch has something plugged into g0/1, then I know the top one is the master).  And as Cisco says switch 2 is the one with the failed power supply, then I know the bottom one is the one to swap out ...
0
 
LVL 13

Assisted Solution

by:kdearing
kdearing earned 167 total points
ID: 35001419
A stack automatically updates all switches to the same version.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_25_see/configuration/guide/swstack.html
"All stack members are eligible stack masters. If the stack master becomes unavailable, the remaining stack members participate in electing a new stack master from among themselves. A set of factors determine which switch is elected the stack master. One of the factors is the stack member priority value. The switch with the highest priority value becomes the stack master."
0
 

Author Comment

by:Elemental12
ID: 35001483
Ok, so I confirmed which physical switch is switch 2.  Once it shows up, I will check the version and downgrade accordingly.  Anything else I need to keep an eye out for ?

Thanks
0
 
LVL 32

Assisted Solution

by:aleghart
aleghart earned 333 total points
ID: 35001664
In general, watch cable position.  Label them accordingly before disconnecting.  When you unplug them, all ports may not be equal.

For instance, did you have one forced to 10Mb duplex, or aggregated with other ports.

When replacing, I was able to move the downed switch 2u down, and mount the replacement.  Then I could move the patch cables over one-by-one.

YMMV.  But it made it easy that I could replicate the cable layout and not have to change any notes or documentation.
0
 

Author Comment

by:Elemental12
ID: 35007011
Thank you for the suggestion of racking first ... Unfortunately, there are items above and below, so I cannot rack ahead of time, but I can label the interfaces before I pull them so I can put them back in the same port on the new one.

0

Featured Post

[Live Webinar] The Cloud Skills Gap

As Cloud technologies come of age, business leaders grapple with the impact it has on their team's skills and the gap associated with the use of a cloud platform.

Join experts from 451 Research and Concerto Cloud Services on July 27th where we will examine fact and fiction.

Question has a verified solution.

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

When it comes to security, there are always trade-offs between security and convenience/ease of administration. This article examines some of the main pros and cons of using key authentication vs password authentication for hosting an SFTP server.
When you try to share a printer , you may receive one of the following error messages. Error message when you use the Add Printer Wizard to share a printer: Windows could not share your printer. Operation could not be completed (Error 0x000006…
Viewers will learn how to connect to a wireless network using the network security key. They will also learn how to access the IP address and DNS server for connections that must be done manually. After setting up a router, find the network security…
Internet Business Fax to Email Made Easy - With  eFax Corporate (http://www.enterprise.efax.com), you'll receive a dedicated online fax number, which is used the same way as a typical analog fax number. You'll receive secure faxes in your email, f…
Suggested Courses
Course of the Month6 days, 8 hours left to enroll

634 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