Hi expert guys there:
my company needs to setup voip on corp LAN. I read cisco stuffs and try to understand the concept. here i have a little confuse and hope u guys provide me some concept information. Here is the sencenario: I have 5 internal vlans for all workstations configured as static IP addresses. now I want to setup all voip phones connect cisco 3750 switch using seperate vlan via DHCP enabled on switch, there are about 500 phones so that I need to create at least 3 extra vlans for phones using DHCP. According to setup, all workstations will connect to phone access port and phone port will connect cisco switch. the question is how to enable phone port to use DHCP while PC use static IP on its own existing vlan? i dont know the concept how it works here. Assuming switch must need DHCP,QoS and CDP features enabled. Any input is welcome, where to find more info that setup, thank you!

According to setup, all workstations will connect to phone access port and phone port will connect cisco switch.

We use Nortel equipment and VoIP phones where I work (thank goodness!). For a while I had a PC connecting through my VoIP phone.

On the switch side of things, the port my phone was plugged into (on the switch) was tagged for our VoIP (DHCP) VLAN as well as the VLAN for the PC subnet.

example:
VoIP = VLAN 5
PC Subnet = VLAN 10

Port on switch that phone plugs into would be tagged with both 5 and 10.

I would imagine Cisco would handle things the same way.

thank for your input, how do I config switch port to tag vlan 5 & 10 in cisco world? what features in cisco switch need to be turn on in order to do that?

oye!

You don't ask for much do you.......LOL.

Ok, assuming your switch has IOS v12.1 or higher (so I can use the "range" command) I will give you the commands for adding VLAN's to interfaces. If you've worked on Cisco's, you know you don't need the entire word for the command (ie: "int" is enough when using the "interface" command) so I'm going to use the short version of commands.

Assuming you've already logged into the switch and gone into priveleged mode, and, the VLAN's have been created (using my above made up VLAN's):

conf t
int range fa0/2 - 5
switch access VLAN 5
switch access VLAN 10
exit
exit
sho VLAN

Starting from the top down:
- enter global configuration mode
- pick the range of interfaces to perform the actions on
- add the VLAN's to the interfaces
- exit interface
- exit global configuration mode
- show status of all VLAN's to verify you've properly added VLAN's 5 and 10 to int's fa0/2 through fa0/5. NOTE: from this point you could also do a sho run to show present running configuration. Look at ports fa0/2 throug 5 and ensure both VLAN's are added to them.

Don't forget, once you've made your changes to save them: write mem

thanks, is it possible assign 2 vlans on single switch port? I tried but it only assign one vlan at a time. any idea?

Commands in cisco for data and voice to be allowed on the same port are as follows.

config t
int range gi1/0/2 - 5
switchport access vlan 5
switchport voice vlan 10
mls qos trust device cisco-phone
spanning-tree portfast
exit

I like long walks, especially when they are taken by people who annoy me.

Also on dhcp to push out your tftp servers for your phones to get the load you can use
option 150 ip x.x.x.x y.y.y.y

Where x.x.x.x is your primary server.
and y.y.y.y is your secondary.

You enter the command:
option 150 ip x.x.x.x y.y.y.y

when configuring your dhcp scope.

I like long walks, especially when they are taken by people who annoy me.

Oops! My bad. Thanks for the correction buckethead.

We're presently phasing out our Cisco switches in favor of Nortel Baystacks so I haven't actually set a Cisco up for VoIP so hadn't realized the command would be "switchport voice vlan 10". I have however set it up on several Nortel Baystack 5520's (PoE capable) and it's a lot simpler.

Anyhow, I hate misinforming people and leading them down the wrong track and I almost did.

thank you all guys input, however, the command "mls qos trust device cisco-phone"
does it mean to tell the voice vlan using QoS feature? any idea how to use QoS on voice vlan? one more question, is it possible I can setup a few DHCP vlans for IP phone (say 500 phones) on the same core switch? Do i have to config all stack member switches ports to be voice vlan so that phone connect to port will be assigned by dhcp vlan while PC connected to phone access port will still appear its own data vlan?
by default, CDP is enabled on cisco switch, do I have to do any setup on IP phone?

i am thinking if my company has about 500 IP phones, should I create a Class B DHCP voice vlan? say 172.16.40.0/22 to accommodate so that eliminate routing issue on layer 3 switch, any idea? Anyone knows DHCP can assign IP address in subnet 172.16.40.0/22 ?

Two options, you can assign multiple vlans (/24s) for 500 phones or like you said create a bigger subnet to accomodate. Plus it is not absolutly necessary to create a voice vlan, although it is best practice the phones will pick up an ip from your data vlan and work just fine. DHCP on a 172.16.40 /22 is the same kind of set up as it is for a 192.168.1.0/24. By the way 172.16.40.0 /22 is not a class B. A /16 is a class B. I think you may be making this DHCP harder than it is. CDP will pick up the phones, no additonal CDP configuration needs to be done. Let me know if you need further clarification.

I like long walks, especially when they are taken by people who annoy me.

thanks, I should clarify 172.16.40.0/22 is a subnet of class B network. from there, there are about 1000 hosts can be assigned in this subnet. As you mentioned I wont need to create voice vlan, what about QoS? how does QoS works in voip network? any resources I can find more about it?

There are multiple docs on the cisco website if you just search 3750 qos. Multiple ways of configuring, keep in mind though that QoS has to be configured throughout your network to benefit from it. It's also very complicated to explain/understand, especially over a forum.

I like long walks, especially when they are taken by people who annoy me.