Setting up DHCP and options for voice vlan

[Colin Higgins]

It has been a while since I configured this, and I can't seem to rememebr the exact way ...

I have 2 VLANS, voice and data. I have a DHCP range set up on the Catalyst 3750 switch for the data vlan, but I am not sure how to go about doing the same thing for the voice vlan, and how the phones will know which pool to pull from. Here is a hypothetical setup

ip dhcp pool Employees

network 192.168.120.0 255.255.255.0

ip dhcp excluded-address 192.168.120.1 192.168.120.20

domain-name mydomain.com

dns-server <servers>

lease 7

interface GigabitEthernet1/0/10

switchport access vlan 10

switchport mode access

switchport voice vlan 11

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape  10  0  0  0

queue-set 2

mls qos trust device cisco-phone

mls qos trust cos

auto qos voip cisco-phone

no mdix auto

spanning-tree portfast

How should I go about congiuring the pool for the phones? Which options do I use in the pool (150?)

thanks

[Ayodeji Okanlawon · Accepted solution]

Your switch config looks okay..You have defined VLAN 11 as the voice VLAN..hence the phones will use CDP to discover they are in VLAN 11..

To create phones DHCP pool, you just need to configure your ip dhcp pool, and the configure option 150 ip with the tftp server ip...You shoudl consider how you will route between the VLANS..and you may need ip helper-address command if the dhcp server is on a different VLAN from the phones

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[Colin Higgins]

If the DHCP server is the switch itself, do I need helper addresses?

[Ayodeji Okanlawon]

Yes, depending on what VLAN the dhcp server is in..If its on the data VLAN then you should configure ip helper command on the voice vlan point to the ip address of the dhcp server

Please rate all useful posts

"opportunity is a haughty goddess who waste no time with those who are unprepared"