Physically swapping out switches

[wwwillster07]

Little bit different of a question.  I'm going to be swapping out the floor closet switches where all the users are connected.

Never fun and generally I just brute force it, config side it good so not terribly worried on that front, but I thought i'd reach out and see what other people generally do, as the boss asked a few questions and it got me thinking.

New switches in the IDF's are going to be larger and the port numbers don't match, going from int gig 1/1 and so on to int gig 1/0/1 so on the config front really just a matter of search and replace even in something as basic as notepad.

The question I really have is insights on how people handle getting the right cables to the correct ports, which are largely unlabeled and in a couple of locations it's a rats nest.  We have a lot of ports that are individually configured and different than the standard user port.  Yes it would be nice if these user ports were all configured exactly alike but they are not.  So there's no mass unplugging and just plugging the new ones into whichever port they reach.

How do you folks out there handle such situations?

[balaji.bandi · Accepted solution]

My suggestions :

1. Capture all ip arp table

2. capture show mac address table

3. capture show interface status

before you doing any work.

4. If you replacing same capacity switch - if the existing switch underneath have space, rack it same place so you can move one cable at a time to same port for the new switch. ?

if that is not the case - you have 2 methods ?

1. buy a lable tag, and tag to each port or

2. buy or use emptry patch pannel plug all the ports to the dummy patch pannel

remove the old switch and rack the new switch and configure, keep plug each cable in right place.

do same steps as mentioned arp , mac, interface status, (if that is matched pre and post you alsmost good).

[wwwillster07]

Yup grabbing the tables I consider as part of the config side and due diligence...

I should have mentioned there's no room whatsoever so yeah, old switch is coming out, cables all need to be unplugged to get the new switch in then all the cables back in.

I so didn't want to label as that just becomes a mess and was hoping someone came up with a brilliant alternative and there you go, a spare dummy patch panel, what a fantastic idea!

anyone else got any ideas out there to share?

[balaji.bandi]

I so didn't want to label as that just becomes a mess 

This hard work pay you next time when you have same Migration - that helps the quality work you did (so next engineer follow you)

take example if you are disaster that will give direction on each cable labled correctly and you plugged in correctly (this cost few quids to lable -but this pay for long run)

so dummy patch pannel we use most time where switch fails and service to restore as quick as possible to save time.

if you planning to replace with time then suggest to LABLE.

[nict]

I totally agree with balaj bandi's approach - Same things I would do.

If possible, I would configure all the new switches before your maintenance window, so you only have to unrack the old switches and rack the new onces and of course do the cables. By doing this, you always verify that both switches types share the same syntaxes.

This is nice to know beforehand, so you don't stand in a situation where you have to use time on finding the right syntaxes for some configuration, in the middle of a maintenance window.

... And another great thing would be to get 802.1x configured, so you don't have to worry about the cables for next time

Good luck with your new implementation!

[Joseph W. Doherty]

For a planned move to another device, the dummy patch panel is a wonderful approach.

Also, of course, labeling the cables works, but would likely take more time, both the labeling, and identifying each cable, in a bundle, for which port they should be connected to.

Another approach would be color coding the cables into functional groups, to correspond to functional switch port groups.  E.g. any green cable can be connected to any port in the range 1..15, etc.

The 3 above approaches are not mutually exclusive, but each has its specific advantages in certain use cases.

Possibly the color coded approach's advantage isn't clear.  In case of an "emergency" movement of cables, you just need to match groups.  For example, in a switch with ports 1..15 in the "green" group fails, you can relocate those ports to any other switch, or switches, (same closet) supporting that functional group, even if the port number differ.  E.g. "green" group might be ports 10..20 on another switch and ports 30..48 on another switch.  (NB: in a closet or rack, I do like, whenever possible, use the same port range, for a functional group, across all the switches [or line cards].  With a single ASIC, line card or switch failure, often I can get ports back on-line, functionally, within minutes, especially, if I have N+1 bank of ports.  Not much longer to swap an, on-hand, spare line card.  A little longer to swap an, on-hand, 24/48 port switch.)

[Leo Laohoo]

First thing we do is generate a list of ports that are un-used for, say, the last 90 days.  

Next, we visit the site and we unplugg everything that appears on that report.  While we are there, we physically inspect the space we are going to shove the new switches in and plan (sequence of events) how to get it done.  Since part of our work is to replace the existing thick copper patch cables with thinner ones, we measure the length of the cables required.  

[wwwillster07]

Awesome insights everyone!  Thanks a million.  Definitely a great topic to discuss.