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Beginner

Unable to connect to Core Switch

Hello All,

I have a problem with extending the LAN on a client site . They are looking to extend the LAN with a 2960S-series switch. Already in place is a 4510 switch which the 2960 is connected to via fibre. The 2 switches are both set up but there is no connectivity as I cant ping between them or anything.

The management VLAN on the 2960 shows line up, protocol down, which I believe means the VLAN is enabled but there is a form of physical mismtach on the ports. I have attached the configs of both switches. I would appreciate if anyone can take a look and help out with what might be wrong. I feel it might be a problem with GBIC module compatibility. The SFP installed on both ends of the switch are GLC-SX-MMD. On the 4510, the SFP sits in a twingig converter (CVR-X2-SFP) but there is no light on it at all when the cables are plugged in.

I need to be sure its not a configuration issue. 

Everyone's tags (3)
40 REPLIES 40
Beginner

Unable to connect to Core Switch

Hy Abayomi,

Well , I'm a fresh CCNP so my answer probably will not help you, but until someone will response...

Firt vlan 5 is up down because no interface is in  access vlan 5. from what i saw all the interface in access are for vlan 100. so i believe when you will configure an interface for vlan 5, it will be up up.

And another thing, from what i see on core, it has port-channel to connect to your extensio, maybe if you try to make a port-channel on the extension the ping will work.

I'm waiting a pro to answer your question.

Best regards,

Dragos Tudor

Beginner

Re: Unable to connect to Core Switch

Thanks a lot for your response dragos, if I understand you well, you are saying that the access ports should also have the management vlan enabled on them? If thats what you are saying, I don't think so, however of you are saying they should be enabled on the trunk ports, they have and the issue still remains.

Beginner

Unable to connect to Core Switch

Hy!

No no, the acces port should not have also the vlan 5, but vlan 5 will shown up down until you will configure a port with vlan 5. You can configure a single port with vlan 5 to see that. that will not influence  the ping . and i see the two switches are leased with a port-channel but i don-t see wich one is active and wich one is passive, and that i think is a big problem.

Best regards,

Dragos Tudor

Enthusiast

Unable to connect to Core Switch

Hi Dragos,

Well it depends on the implementation as you can see here :

http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a0080160b14.shtml

You will eiter see interface vlan down, down or up,down.

But in these configuration files you can clearly see that a trunk is configured with vlan 5 allowed on it. Therefore I think that the problem will be not resolved by configuring an port associated with vlan 5.

Best regards,

Jan

Beginner

Unable to connect to Core Switch

Hy Jan,

Agree with you, but what do you say about port-channel configuration, i don't see what is active/passive.  maybe this is the problem...

Best regards

Dragos

Enthusiast

Unable to connect to Core Switch

Hi Dragos,

thank you! Well keep on searching with me . Maybe it could be in port-channel configuration, better check out if the port-channel is formed if there is no spanning-tree instance for vlan 5.

Best regards,

Jan

Beginner

Re: Unable to connect to Core Switch

thanks for your help Jan( I have got a friend who is called Janko but shortens his name to Jan though I call him Janko all the time so I just assumed...lol)...upon issuing the command and checking I am still getting the same thing "no instance of spanning tree exist for vlan 5"....it proves it's more than spanning tree like u said...brought in new SFP's just to check but still no luck....

Sent from Cisco Technical Support iPhone App

Enthusiast

Re: Unable to connect to Core Switch

Hi Abayomi,

well in my experience interface vlan Up, Down is seen when STP is misconfigured. Make sure that STP for the management vlan is up and running!

sh spanning-tree vlan 5

(I believe that vlan 5 is your management vlan)

Hope that Helps.

Best regards,

Jan

Beginner

Re: Unable to connect to Core Switch

thanks a lot Janko, I get "no spanning tree info available for vlan 5" when I issue the command.

However on enabling it for vlan 5 and doing the show command to check, I still get the same thing, no spanning tree info available for vlan 5...dunno whether I need to enae it for the physical interface connecting to the core switch... What do u think?

Enthusiast

Unable to connect to Core Switch

Hi,

you're welcome. Have you tried sh spanning-tree vlan 5 or sh spanning-tree interface vlan 5? Because I made an mistake and then I edited the post .

sh spanning-tree vlan 5 is what we need here.

Best regards,

Jan

Beginner

Re: Unable to connect to Core Switch

hi Janko, sorry I did it for int vlan 5. So for vlan 5, should the stp type be auto or IEEE?

Sent from Cisco Technical Support iPhone App

Enthusiast

Unable to connect to Core Switch

Hi Abayomi,

First of all - how do you know the other form of my name?

And the second thing, would you be able to actually paste the output here?

I see in your configuration setting that you are running rapid-pvst. So the output should not show IEEE but rstp - if we are talking about Spanning tree mode.

Something like:

Switch#sh spanning-tree vlan 5

VLAN0005

  Spanning tree enabled protocol rstp

I'm still looking through the configuration files to see if something isn't wrong.

Best regards,

Jan

Beginner

Re: Unable to connect to Core Switch

Sorry Janko, do u have the syntax to enable it under vlan 5? When I do sh spanning-tree vlan 5, I get spanning-tree instance for Vlan 5 does not exist

Sent from Cisco Technical Support iPhone App

Enthusiast

Unable to connect to Core Switch

Hi Abayomi,

Well there we have it! I hope so... If everything is fine and just somehow the vlan 5 is missing it can be added by issuing command:

Switch(config)#spanning-tree vlan 5

But I have a bad feeling something else is going on here. Because from the configuration files I see, It just seems to me that the switch should have created instance for vlan 5 automatically.

Best regards,

Jan

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