3550 voice over ip

[darryl.hobbs]

I have a new customer with multiple 3550 SMI. I need to put in a voice over ip network for them. The 3550's will be performing the layer 3 routing. The IP phone system is from Mitel. The ip phone system is looking for 802.1q tagged packets for the voice and untagged packets for the data. My question is will I need to implement the Cisco's voice vlan solution to tag the voice packets? If not how will I tag the voice packets?

[andrew.butterworth]

Voice VLAN's (or auxiliary VLAN's) are simply access-ports that have an un-tagged access VLAN and one tagged VLAN (the voice VLAN). In addition to this Cisco switches advertise the Voice VLAN via CDP so Cisco IP Phones can use this VLAN. The following configurations would give the same result:

interface fastethernet0/1

switchport mode trunk

switchport encapsulation dot1q

switchport trunk native vlan 10

switchport trunk allowed vlan 10,100

!

interface fastethernet0/1

switchport mode access

switchport access vlan 10

switchport voice vlan 100

The newer Mitel phone firmware supports the CDP detection of the Voice VLAN. For the earlier firmware phones they initially transmit packets without any tagging but should receive via DHCP a vendor-specific option for the VLAN id. They then restart using the VLAN tag.

I have used the Cisco Voice VLAN feature with Mitel IP Phones but the QoS settings need tweaking due to the differences between the Mitel & Cisco implementations.

Good luck

Andy