Ethernet Switches & Routers

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New Contributor
Posts: 2
Registered: ‎10-27-2016

mac-address table displays impossible connection

I did a show mac-address | include xxxx.xxxx. using the first 4 octets from the mac of another switch. The results showed a mac address belonging to a port with copper media connected to a port with fiber (sfp) media. How can this be? FESX448 connected to ICX6610 On the FESX448 i do the following: FESX448# show mac-address | include fa68.7248. I get the following results... FESX448#show mac-address | include fa68.7248. fa68.7248.9278 2 Dynamic 1454 23 The problem is...that mac address belongs to a copper port, and port 2 on the FESX448 is fiber. What gives?
Brocade Moderator
Posts: 77
Registered: ‎02-04-2015

Re: mac-address table displays impossible connection

Hello,

 

Is this the only mac address you see on port 2?

 

Sometimes, ICX advertises its Managment MAC when the port first comes up. this usually disappears after a while.

 

You may issue command "show chassis" on the ICX and confirm the BootProm/Management MAC.

 

Regards,

Os 

Any and all information provided by me is not reviewed, approved or endorsed by Brocade and is provided solely as a convenience for Brocade customers.

All systems and all networks are different and unique. If you have a service affecting network problem, please open a TAC service request for service through Brocade, or through your OEM equipment provider. If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution" .
New Contributor
Posts: 2
Registered: ‎10-27-2016

Re: mac-address table displays impossible connection

I should restate my question. How can I figure out which ports are the uplinks between two switches? Can't I do that by looking at the mac tables?
Brocade Moderator
Posts: 77
Registered: ‎02-04-2015

Re: mac-address table displays impossible connection

Hello,

 

You can, although it is not the ideal way since ports connecting switches carry multiple MAC addresses. If you see 2 MAC addresses belonging the same switch, one might be the Mgmt/BootProm MAC Address as I mentioned in my previous reply 

 

LLDP is the best way to check uplink neighbour switches.

 

Regards,

Os 

Any and all information provided by me is not reviewed, approved or endorsed by Brocade and is provided solely as a convenience for Brocade customers.

All systems and all networks are different and unique. If you have a service affecting network problem, please open a TAC service request for service through Brocade, or through your OEM equipment provider. If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution" .
Contributor
Posts: 22
Registered: ‎05-21-2014

Re: mac-address table displays impossible connection

Make sure you enable FDP on the Brocades (fdp run).  Issue the command "sho fdp neighbor" to see the connected switches.

 

If you have the Brocade connected to a Cisco switch, ensure cdp is enabled on the Cisco and on the Brocade (fdp run, cdp run).  Then issue a "show fdp neighbor" from the Brocade.  It will identify any Cisco switch with an asterisk.  You cannot issue a "show cdp neighbor" from the Cisco and see the Brocade.  It will only work from the Brocade.

 

 

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