Adding support for IP Telephony to network

Question

We are in the process of getting a new phone system. The new system is capable of supporting Voice over IP and the "phone" guys are saying they are going to test and move to IP phones. They have also talked of creating IP Trunks between various remote locations for phone service and/or voice mail support. Other than the phone systems we are a complete Cisco shop.
My network consists of the following...
4506 as my core with 3560s in each floor IDF as distribution
2950s are connected to the 3560s to serve as access
3750 stack supporting my server farm
I run several VLANs and have been trying to figure out to fit the new PBX and VoIP into the infrastructure. I run the following VLANs ..
One VLAN for each floor (VLAN2, VLAN3, VLAN10)
One VLAN for the server farm (VLAN4)
One VLAN for network device management (VLAN5)
One VLAN for the IS department (VLAN6)
One VLAN for our wireless network (VLAN7)
I do not use VLAN 1 for anything
I have been reading through topics and docs on-line looking for what needs to be changed network wise to support this. I know that I will need to create additional VLANs to support the voice traffic and will create one for each floor. It appears that I need to create trunks between the access switch and IP phone and including the data VLAN as well as a voice VLAN. The is where the questions start.
1) What is the difference in the access VLAN and a voice VLAN? The samples I have seen use these instead of a restricted vlan to flow on the trunk.
2) The devices in the PBX that need to be part of the "voice VLANs", do I define them as access VLANs or voice VLANs? This would include the "IPSI", "C-LAN" and "MEDPRO" cards in the PBX. Since this handles signaling and is needed by the VoIP calls I am figuring they will be in one of te voice VLANs.
3) Do I need to do anything from a QOS standoint to keep things flowing smoothly through the switches?
4) I have no clue about what is needed to support IP Trunking across my WAN.

Answer 1

Brent, i have thousands of avaya ip phones on my cisco network, with no issues. a couple pointers.
1) Aux/voice vlans work with avaya phones so u don't have to use setup explicit dot1q trunks.
2) avaya phones now can use HTTP or HTTPS instead of an TFTP server for firmware image updates...i use IIS and apache in my enviorment for this. or you can use the avaya server perform this task, since it runs redhat enterprise linux.
3)yes dhcp on a router works fine with option 176 setup as ascii example:
ip dhcp pool local-dhcp-pool
import all
network 172.29.28.16 255.255.255.248
default-router 172.29.28.17
dns-server x.x.x.x x.x.x.x
domain-name xxx.com
netbios-name-server x.x.x.x
netbios-node-type h-node
option 176 ascii "MCIPADD=172.24.99.200,MCPORT=1719,HTTPSRVR=172.24.98.250"
4) you might want to look at planning for "Network Regions".. in essece it the the logical group or mapping of ip address on the avaya system. Here'a a good document so you catch my drift:http://www.avaya.com/master-usa/en-us/resource/assets/applicationnotes/netw-region-tutorial.pdf
5) all avaya ip endpoints can perform both layer2 (cos) and layer 3 qos tagging(diffserv).(and the phone can re-write l2q cos tags if required) this configuration is done on the avaya media server and is sent down to all ip devices once registered.Also ensure the data switch ports with avaya ip phones and gateways(clan/medpro modules) have qos trusting enabled...example :
mls qos trust dscp (or)
mls qos trust cos
hope this helps!