2 Vlans Stopped Communicating

[ccoperryc]

Our School District has 25 buildings and each have it's own vlan assigned to it. Recently one of our building vlans, 111, just stopped communicating with another, 157, but does communicate with the remaining 23 vlans. Vlan 157 is not able to communicate with vlan 111 but can communicate with the other 23 vlans.

We have a 6509 sup720 running CatOS with 3500 series edge switches.

Any suggestions on where to start looking would be greatly appreciated.

Cathy Perry

WWCSD Tech Group

[Jon Marshall]

Bruce

This was my thought too but Cathy says that servers are connected directly into the 6500 switch. So i thought it might just complicate things to start checking trunk links to access-layer switches etc.

But might be worth a try.

Jon

[ccoperryc]

Jon,

You are correct both servers connect directly to the 6500. I have looked at the module ports for both servers several times and can confirm that both ports are set to allow all vlans through.

As I have been reading the different posts I have been pouring over configurations from different points in time from the 6500 and two things continue to stick out to me:

PortInstanceCost on the Sup 720

and

Control Plane on the MSFC.

Is there any remote possiblity that either of these could be the cause?

I will run the trace routes on Friday for you as requested in an earlier post.

Thanks to all,

Cathy

[lamav]

Cathy/Jon:

Not to be a budinski, but how about Cathy just post the entire 6500 switch config so we dont have to keep guessing what the configs are?

Just a thought instead of shooting in the dark...

Thanks

Victor

[lamav]

Cathy:

Is it fixed?

VL

[ccoperryc]

Still having issues.

Thank you for asking.

Cathy

[t814687]

is it feasible for you guys do this after hours:

shut

no shut

on the VLAN interfaces you are having issues.

this should clear the cef tables....

-serg

[ccoperryc]

Serg,

That could be a definate possibility I would have to schedule it through our Network Administrator.

Let you know.

Thanks

Cathy

[lamav]

Cathy, sorry to hear it.

If you decide to reboot the switch, do not forget to do a 'wr mem" on the MSFC so that you dont lose any unsaved configurations.

After that, do the reboot on the supervisor and the MSFC.

Thanks

VL

[ccoperryc]

Serg,

Id the shut no shut on the two vlans having problems. No change in the status.

Thanks for the suggestion.

Cathy

[t814687]

Cathy,

from configuration perspective the configs of 6509 look pretty normal and if there is no any acl involved the directly attached subnets should talk to each other. Unless people have any other ideas I would schedule a reload of the box at some time after hours.

Think about that...

-serg

[lamav]

I agree with Serge. You've been playing footsies with this for days.

Save config and reload.

If that doesn't work, you may be able to apply one last resort to the switch:

http://www.timbertools.com/Images/handtools/djaerf_axesLG.jpg

HTH

Victor

[ccoperryc]

Victor,

Thank you for the support and humor.

We have discussed and agree that we are at the point of a reboot and will be scheduling this soon.

Cathy

[lamav]

OK, cool. Let us know what happens, for sure.

Victor

[dmooreami]

Humm, I had a very similiar problem. see my post here:

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=LAN%2C%20Switching%20and%20Routing&topicID=.ee71a04&fromOutline=&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.2cc07deb

Short was one vlan could not even ping its default l3 gateway. had to remove the interface in the IOS and re-apply it.

All L3 Vlans on the switch could ping the problem Vlans L3 gateway. It was like the marriage between the L3 and L2 in the cat where broken and not talking. I onl have Sup2's, not fancy 720's like you do. :)

[ccoperryc]

Found something very interesting last Thrusday morning after getting this post in the Cisco Forum.

I can ping the gateway for Vlan 157 (AMS) from the server in vlan 111(SMS) with no problem. (ping 10.91.48.2 from 10.91.72.4 server)

I cannot ping the gateway for Vlan 111(SMS) from the server in Vlan 157 (AMS). (ping 10.91.72.2 from 10.91.48.4 server)

Any thoughts?

Thank you

Cathy