VLAN related question

[rajuswarnakar]

Hi,  Have

a question on VLAN. If a switch is configured with

VLAN Interface and connacted to a core switch, what is the

best possible way to locate the switch management IP to login remotely?

[snakayama]

Hello,

The following Cisco's document

Best Practices for Catalyst 6500/6000 Series and Catalyst 4500/4000 Series Switches Running Cisco IOS Software
http://www.cisco.com/en/US/partner/products/hw/switches/ps700/products_white_paper09186a00801b49a4.shtml#topic4

said that

==========
Make the management VLAN a VLAN other than VLAN 1. Keep all user data out of the management VLAN. Instead, configure a loopback0 interface as the management interface on each switch.

The arrangement separates management traffic from user data.
The management IP address is in a separate subnet, VLAN, and switch for security.
There is higher assurance for management data delivery during network failures.
There is no active spanning tree in the management VLAN. Redundancy here is not critical.
==========

Your switch may not be Cat6500/6000 or 4500/4000 but I think it useful information for you.

Regards,

Shinichi

[rajuswarnakar]

Hi Shinichi,

    Thank you for the reply. But my question was apart from the configuration. Probably I was not so cleared according to my question, sorry. My question was, if I need to locate any perticular switch, which is connacted to core switch through VLAN interface, how can I do that. Through cdp neighbour it will not show.

Regards,

Raju

[snakayama · Accepted solution]

Hi Raju,

Sorry for my misunderstanding.

Is your question how we can find out the IP address of access switches connected to core to execute remote login, but can not get the information from CDP because of CDP not working?

If so I think this is difficult question but I might execute the following procedure.

It assume that I know which port on core connected to access switch I want to remote login to

(1) On core examine MAC address table

(2) From the result of (1), pick MAC addresses out on the port to which connected access switch

(3) examine the OUI of those MAC addresses to find out which MAC address belongs to vendor of access switch

For example, I pick xxxx.xxyy.yyyy as MAC address out from (2).
Go to http://standards.ieee.org/regauth/oui/index.shtml and enter xxxxxx as OUI into "Search for:" field , and then the result is displayed as follows,

      xxxxxx        xxxxx, Inc.

(4) On core examine ARP entry find out IP address which has MAC address matches the result of (3), in this case xxxx.xxyy.yyyy.

(5) I try to remote login to the IP address which get from (4)

I still misunderstanding your question but I hope this help to you.

Please rate if this help you.

Regards,

Shinichi

[rajuswarnakar]

Hi Shinichi,

   This time you didn't miss understood my question. Thanks for the answare.

Regards,

Raju Swarnakar

[deyadav]

Hi Raju,

As far as I know, there is no way to get that information. CDP always advertises the lowest Vlan's IP address in it's updates. Probably try to use lowest Interface Vlan for management:

https://www.ciscotaccc.com/kaidara-advisor/lanswitching/showcase?case=K79493067

I am not sure which devices use this command, but most of the switching platforms don't:

cdp source-interface 

This may help CDP to advertise the intended interface's IP.

Regards,

Deepak