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Community Member

MGT port on a 4948

How is the MGT (Not console) port on the 4948 configured?

I cannot locate instructions for this in the documentaion for this device.


Re: MGT port on a 4948

Established physical link 100MB Full Duplex

Network layer connectivity may take a few seconds

The MGT port auto-negotiates speed and duplex with the connected device. Currently, you can not hardcode speed and duplex settings. Since this port is available only in ROMmon mode and for TFTP only, it is not a major concern if the speed and duplex are mismatched due to any potential auto-negotiating problem. The TFTP application has an internal packet loss mechanism to prevent any corruption of the system image being downloaded.

Issue the

set interface fa1

command to configure an IP address for the 10/100 MGT port, as this example shows. If the subnet mask is not specified, the IP address would take the default classful mask.

rommon 7 >set interface fa1

Issue the

set ip route default

command to configure the default gateway for the switch to use to get to the TFTP server, as this example shows. The default gateway should be a routing device in the same subnet as the IP address configured in above step.

rommon 8 >set ip route default

In ROMmon versions earlier than 12.1(12r)EW, even if the TFTP server is in the same subnet as the 10/100 MGT port, you still need to configure the default gateway by issuing the set ip route default command. If you are directly connecting your PC, which has the TFTP server application installed, use the IP address of the PC for the default gateway IP address. If the default gateway is not configured, the TFTP can not be performed. This restriction is resolved starting in ROMmon version 12.1(12r)EW or later. You do not need to specify the default gateway IP address if the TFTP server is in the same subnet as the management IP address.

Issue the set command to verify the configurations which have been made.

rommon 11 >set

PS1=rommon ! >





RET_2_RTS=13:36:46 UTC Tue Aug 15 2000









Ping the TFTP server to ensure that there is connectivity to the server from the MGT port on the Supervisor Engine. Enter the ping command, as this example shows:

rommon 9 >ping

Host is aliveIf the ping is not successful, troubleshoot the IP connectivity issue from the default gateway to the TFTP server. If the TFTP server is the same subnet, make sure it is configured with the IP address you are pinging. Refer to Common Problems in Installing Images Using TFTP or an RCP Server for more information.

Once the ping to the TFTP server is successful, you can issue the boot tftp:/// command to specify the system image which is available in the TFTP server to boot the Supervisor III.

rommon 6 >boot tftp://

hope this helps.



Community Member

Re: MGT port on a 4948

Hello Salman,

Thanks for the insight.

Community Member

Re: MGT port on a 4948

Hello Salman,

As a follow-up. Once this port has been configured and the IOS is running, is this

port for only snmp read/write access?


Re: MGT port on a 4948

The 4948 management port exists because the the 4948 is actually a cat 4.5k sup V. The cat 4.5k supervisors have a management port because Cisco needed a consistent interface for disaster recovery of the switch. They couldn't code rommon for every line card that might be produced so they put 1 interface in the sup itself.

That said, the mgmt interface has no use after the switch boots. I suppose you could leave this interface connected to a segment that is used in the event that Something Bad(tm) happens. Just add in a terminal server.

Community Member

Re: MGT port on a 4948

Great, thanks for the knowledge.

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