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VOIP switch port config best practices


Hi there.  I've got a Cisco infrastructure, but a non-Cisco VOIP platform (Mitel 3300).  I've been experiencing some call quality issues lately, so I was reviewing port configs on the access switches at three of my corporate sites.  These switchport configs were setup before I joined the company, and seem to have been setup by different people at different times and with different intentions (ie. wildly varying config).    

The access switches at each site tend to be Catalyst 3750 POE, but the switchport config can vary:

eg.  Site A:

interface FastEthernet1/0/10

description typical VOIP switchport

switchport trunk encapsulation dot1q

switchport trunk native vlan 111

switchport mode trunk

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape  10  0  0  0

mls qos trust cos

auto qos voip trust

spanning-tree portfast trunk


eg. Site B:

interface FastEthernet3/0/10

description typical VOIP switchport

switchport access vlan 122

switchport mode access

switchport voice vlan 120

spanning-tree portfast


eg. Site C:

interface GigabitEthernet1/0/10

description typical VOIP switchport

switchport mode access

switchport port-security maximum 5

switchport port-security

switchport port-security violation restrict

srr-queue bandwidth share 1 30 35 5

priority-queue out

mls qos trust cos

macro description USERS

auto qos trust

storm-control broadcast level 70.00

spanning-tree portfast



Most of the end user work areas have a single LAN drop, and we connect the Mitel VOIP phone to that, and connect the user's PC/laptop to the phone's PC port.  Also, between all corporate sites, there is a 50 Mbps TLS service, provided by our ISP/telco, and we have a separate Mitel 330 VOIP switch at each site.

What is the best config, given my requirements and above, for my Cat 3750 POE switchports in order to best concurrently support data and VOIP traffic?  Are any of the above examples good enough?

Thanks so much in advance,

- Jeremy

1 Reply 1

Leo Laohoo
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VIP Community Legend

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