Switch port configuration for a pc and IP phone

[abhdivak]

Hello,

Can anyone tell me how to configure a switch port for a pc and IP phone. If we are assigning singe port to two different vlan, how switch will separate traffic ? 

Regards,

Abhijith

[Diana Karolina Rojas]

Hello!

You have to configure the voice vlan, example:

interface FastEthernet0/3
switchport access vlan 626
switchport mode access
switchport voice vlan 627
switchport port-security maximum 2
switchport port-security
switchport port-security aging time 2
switchport port-security violation restrict
spanning-tree portfast
spanning-tree bpduguard enable

Regards,

--Do not forget to rate useful post--

[Julio E. Moisa]

Hi 

As Anaid mentioned you can use the "auxiliary vlan" for voice, it will be configured as above:

switchport voice vlan <Voice vlan ID>

Now in order to obtain IP through DHCP take in consideration some parameters to be included on the DHCP server, I think each manufacturer  uses different parameters. 

This link can be useful to understand how it works:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2950/software/release/12-1_11_yj/configuration/guide/scg/swvoip.html

:-)

[Joseph W. Doherty]

Anaid shows an example for how to configure a port.  BTW don't forget, generally you connect the VoIP phone to the switch port and the PC to the VoIP phone.

As to your question, how does switch separate the traffic, its via VLANs.  Basically the same as if you had a PC connected to one port with say VLAN X and your VoIP phone connected to another port with say VLAN Y.

[Julio E. Moisa]

That is correct, The voice vlan should not be the same than data vlan because it could generate voice degradation.

[Joseph W. Doherty]

The voice vlan should not be the same than data vlan.

"Should" being the operative word.

You can have PC hosts and VoIP hosts on the same VLAN, but then each host will see the other kind of hosts broadcasts.  Especially for VoIP, you don't want your VoIP phones to deal with traffic they don't want or need.

Although VLANs separate broadcasts, when you share a port for both a PC and VoIP phone, the port is sharing its bandwidth.  Port based QoS, to give egress priority to VoIP traffic, would be highly recommended.

Also, BTW, some VoIP phones internal switching is suboptimal, i.e. a PC might be slowed by a VoIP phone even when there's no VoIP traffic.

[Julio E. Moisa]

Hi

I agree with you using QoS to prioritize the voice traffic:

The following link could be useful:

http://www.cisco.com/c/dam/en_us/about/ciscoitatwork/downloads/ciscoitatwork/pdf/Cisco_IT_Case_Study_IP_Telephony_Management.pdf

[abhdivak]

Hi Joseph,

Thanks for replay. I understood that we are using two different VLAN. My question is that if a packet coming from PC, how the switch port will identify that is coming PC not from IP phone?

[Joseph W. Doherty]

Generally frames from the PC are untagged (those from the VoIP are tagged).