05-14-2008 02:09 AM - edited 03-05-2019 10:58 PM
Hi,
If i enable voice and data VLAN in the same port how will the IP phones get an IP address from DHCP. MY current configuration is trunk for the phones. Will there be a performance issue on both the configurations. ( Trunk and voice VLAN). Which is the good practice.
Also a small query,
How the PC and phone will get a seperate IP if the PC is connected to the Phone, while the phone is configured to voice VLAN.
05-14-2008 02:15 AM
Hi,
One more question:
Is there encapsulation happening for the voice packets if its under voice VLAN.
05-14-2008 02:59 AM
If u define the same vlan for phones and PC they will in the same broadcast domain hence they will get the IP address from the same subnet.
If u r using a seprate vlan for voice then u can define a seprate subnet for phones.
The best practice is to have seprate vlans for pc and phones.
U r going to define the switch port in data vlan and voice vlan.The switch is going to sense the presence of the voice device and place it in the voice vlan defined on the port so as the vlan=broadcast domain it is going to get the ip from the specified subnet.
Thanks
Mahmood
05-14-2008 04:54 AM
This is how our ports are configured....
interface GigabitEthernet1/4
switchport access vlan 124
switchport mode access
switchport voice vlan 224
qos trust cos
qos trust device cisco-phone
auto qos voip cisco-phone
tx-queue 3
bandwidth percent 33
priority high
shape percent 33
spanning-tree portfast
service-policy output autoqos-voip-policy
Here is how our VLAN's are configured
interface Vlan124
description 24th Floor Workstations VLAN
ip address 192.168.124.1 255.255.255.0
ip helper-address 192.168.2.43
no ip redirects
ip pim sparse-mode
interface Vlan224
description VoIP 24th floor
ip address 192.168.224.1 255.255.255.0
ip helper-address 192.168.2.43
Hope this helps.
Burleyman
05-14-2008 05:49 AM
Its good to have separate subnets for data & voice vlan. When you specify different vlans on switchport for voice & data then voip phone behaves as if the port was trunk & sends voice pkts as tagged. On the other hand, pc's in data vlan send its pkts untagged as in case of native vlan on trunk port.
Its preferred to keep the port as access port & configure it as in the above post.
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: