Setting up a voice and data vlan on a switch

[skk391]

Hi all,

I wanted some advise on how to setup the following please. I have a need to setup a network with a voip telephone system. At the moment I have a CAT 5 cable out of the switch going into a non-cisco phone and then another cable coming out of the phone and going into the PC. Both are supplied IP address from one DHCP server and both are on the same IP range.

I have read that the correct way to configure this is to setup a separate Voice and Data VLAN. slightly unsure on how to do this...

Would it be...

sw1# config t - vlan 10 - Description - Voice Vlan
I take it that there is no need to create a data Vlan I can use the Native Vlan.

Then on each interface which is connected to the phone I need to do the following ...

config t - switchport mode trunk ( to allow both vlans to send frames across this interface )
Switchport voice vlan 10 ( informs the switch that vlan 10 is the voice vlan )

I will then have to create two dhcp groups on my dhcp server and create two Ip ranges one for the voice phones and another for the data.

I'm very confused on how this actually works. How will the dhcp server know which device to assign which range to for example if my phone range is 192.168.0.x how will it know not to assign this range to a dhcp request made by a PC?

Im generally confused about the whole process and could do with a little guidance. I have also read up about lldp and any information regarding this would also be very helpful as my phones are not cisco

Thanks

 

[stubnski]

--> I assume it's a kind of ignorance thing where they don't actually understand what's going on with the frame header.

Vince - What is happening with the frame header? I am truly curious as I have gone from a Cisco phone world to a non-Cisco(polycom) phone world and the same setup works for both vendors, ie switchport voice vlan.

Using voice vlan with LLDP does the same job as a trunk, tagging voice traffic in a separate vlan while keeping the port as an access port, so why would a port setup as a trunk be better? Plus, voice vlans are very easy to look at a port and know what is voice and what is data. I personally do not like to setup ports as trunks to end user devices (Yes, voice vlan + data vlan is technically a trunk).

 

[skk391]

Hi All, Im in need of some help please. I stuck, I mean really stuck

I wasn't getting anywhere with registering my phones with the two vlans so I just gone back to basics. I got rid of all the telephony kit at the moment

here is my config

Switch#show config
Using 2869 out of 524288 bytes
!
version 12.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Switch
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
switch 5 provision ws-c3750-48p
system mtu routing 1500
no ip subnet-zero
ip routing
!
!
!
!
!
!
!
!
!
!
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
!
!
!
interface FastEthernet5/0/1
!
interface FastEthernet5/0/2
switchport access vlan 100
switchport mode access
!
interface FastEthernet5/0/3
!
interface FastEthernet5/0/4
!
interface FastEthernet5/0/5
switchport access vlan 100
switchport trunk encapsulation dot1q
switchport trunk native vlan 100
switchport trunk allowed vlan 100,200
spanning-tree portfast
!
interface FastEthernet5/0/6
switchport access vlan 100
switchport trunk encapsulation dot1q
switchport trunk native vlan 100
switchport trunk allowed vlan 100,200
spanning-tree portfast
!
interface FastEthernet5/0/7
!
i
!
interface FastEthernet5/0/16
!
interface FastEthernet5/0/17
switchport access vlan 100
switchport mode access
!
interface FastEthernet5/0/18
switchport access vlan 200
switchport mode access
!
interface FastEthernet5/0/19
!
i
!
interface Vlan1
ip address 172.16.0.1 255.255.0.0
!
interface Vlan100
description Data
ip address 192.168.10.1 255.255.255.192
!
interface Vlan200
description Voice
ip address 192.168.10.65 255.255.255.192
!
ip default-gateway 192.168.10.65
ip classless
ip http server
ip http secure-server
!
!
!
control-plane
!
!
line con 0
line vty 5 15



so I have my data vlan 100 and a voice vlan of 200.
I have a laptop in fa 5/0/5 with a vlan 100 address 192.168.10.10 /26 and another in fa 5/0/6 with a vlan 200 address of 192.168.10.66.
both laptops have the correct default gateway of vlan 100 = 192.168.10.1 & vlan 200 = 192.168.10.65

I have ip routing enabled but I cant ping from laptop to laptop which I should be able to. If I plug in the laptops into fa 5/0/17 & 18 all is find, I can send my pings around.

I have tried to remove the config and use the voice vlan command instead but I still cant ping across the different subnets. Strange? or im I missing something pretty straight forward!

any idea's please

 

[VinceWhirlwind]

portfast TRUNK".

The Microsoft OS has a security process which blocks ICMP that's being routed. That's why it works when the two laptops are on the same subnet.

 

[VinceWhirlwind]

Hang on, I didn't read what you wrote properly.

The laptop in 5/0/6 isn't going to work as it's on a tagged VLAN. Laptops generally don't have ethernet cards capable of doing 802.1q.

The purpose of having a laptop on an Access port configured in VLAN200 is to test your DHCP is working for VLAN 200, and your inter-VLAN routing is working. That's what you've done with ports 17 & 18.

Now you need a phone in port 6 to test it can register with the voice server/gateway.