Switch Port config for ATA

Unanswered Question
Jan 29th, 2008
User Badges:

Dear All,

Please elaborate on the following config,,,

interface FastEthernet0/24

switchport mode access

switchport voice vlan 999

no mdix auto

spanning-tree portfast

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
jeroenhermans Wed, 01/30/2008 - 00:58
User Badges:


Switchport mode access means this is an access port and not a trunk port for instance.

Switchport voice vlan means any voice device (determined by CDP) you connect will be put in vlan 999.

no mdix auto means you will need to connect to this port with a straight through cable. if you turn it on, it means you can use a cross or a straight through and the port will adjust itself with whatever is needed.

Spanning tree is used to avoid loops in your network. if your switch is connected with more than 1 connection to the backbone for instance, spanning tree is used to make sure you have no loops.

Portfast will make the the connection come back on line faster after there has been a connection loss on 1 of the redundant uplinks.

Hope this helps (please rate if it does),


jhasen Wed, 01/30/2008 - 01:06
User Badges:

The "switchport host" macro available in most of the Catalyst IOS based CLI is a very useful tool to optimize the port for a host connection, the switchport host command sets switch port mode to access, enables spanning tree Port Fast, and disables channel grouping. Only an end station can accept this configuration, of course.

Hope this also helps

sohaildxbfze Wed, 01/30/2008 - 05:03
User Badges:

Hi again,

My qs was not to ask function of each line..

my qs was to have configuration possibilities @ 3560POE with ATA!!!!!!

MARTIN STREULE Fri, 02/08/2008 - 11:46
User Badges:
  • Silver, 250 points or more

This config puts ATA in the Voice VLAN correctly.

Be aware that if you have "mls qos" enabled on the switch this port will not be trusted and TOS/COS will be set to zero in this case.

On the port "mls qos trust dscp" will do.

I encoutered problems with ATAs with "mls qos trust device cisco-phone".

It's a lot easier to give correct answers if the questions are clear. :-)



This Discussion