Nortel 460 and VLANs with voip

[PhilKGH]

We are attempting to implement voip with VLANs over Nortel 460s. The intention is to run both a PC and an ip from the same switch port. We plug the phone into the switch port then plug the PC into the phone. My understanding is that we need to tag the port, then the phone listens on one VLAN and passes packets for the other VLAN on to the PC.

If we have PCs on VLAN1 and phones on VLAN2, what do we need to do in terms of VLAN ids, PVIDs and tagging? Also, do we need to route between VLANs? We have been trying without routing and without much joy so far.

Regards,
Phil.

 

[joca12345]

Phil,

The way I have this working is VLAN-A = Voice, VLAN-B = Data.

The default vlan is VLAN-B, this means the pc does not need to tag any packets.

The phone (i2004 in my case) uses DHCP to get its details. This involves the phone requesting its IP details initially on VLAN-B, the dhcp details that are returned provide the VLAN id for VLAN-A (the voice vlan). The Phone then requests DHCP again this time on VLAN-A and gets the correct IP details for this VLAN.

VLAN-A in Nortel terms is the T-LAN this VLAN needs to have connectivity to the Signalling servers and Call server.

I have not currently got access to my dhcp server to remind me of the DHCP atrributes you require for the phones. But I know there is a public available doc on the nortel site.

 

[PederChr]

Under VLAN and port config.
Untag PVID Only will help you.

PC = VLAN 1 (pvid=1)
Telephon VLAN 2 (pvid=1)

peder alfa ipnett dot no

 

[VOIPaintEASY]

That is the exact same way our 460's put the phones on the VOIP VLAN. Key item is to make the 460 ports a member of both voice and data VLAN's but the PVID or default VLAN needs to be the data VLAN so it can find the DHCP server to get started.

 

[PhilKGH]

OK. We have come to the conclusion we have to do it as per joca12345's reply above. The question is, how do you tell the DHCP server to return VLAN ID in its DHCP offer? Looking through all the DHCP options on the DHCP server, there are none related to VLANS.

Regards,
Phil.

 

[PederChr]

you have 2 different VLAN?
And a router/ fw ?

If you got a fw/ruter you add a ip helper on the interface, and tell it to forward dhcp request to the DHCP server. (ip helper convert a mulicast to unicast)

The DHCP server will find the matching scoope based on the ip helper source address, and assign a ip address..

If you don't have a fw/ router I think you need to have a dhcp server on the same VLAN as the telephone

 

[goodingsd]

You need to setup each switch port for a collocated VoIP phone / PC to be an Untag PVID only with the default VLAN ID for the port set to the PC VLAN.

The phone boots up in the default VLAN and gets a response back from the DHCP server telling it which VLAN to be in. For the i2004 phone DHCP server returns (among the usual IP add, gateway, mask) a site specific string option 144 or 191 with format
The format of the String for the 144 or 191 Site Specific Option is:
VLAN-A:vvvv.
Where: “A” = Hardware Revision of the i2004 IP Phone
“vvvv”= The VLAN ID in Decimal
There must be a colon ) separating the Hardware Revision from the VLAN ID. The string must also end in a period (.)

The i2004 phone switch goes from default to the specified VLAN and then rebroadcast to the DHCP server within the subnet setup for the non-default VLAN. The DHCP server will respond with the normal IP stuff but the phone needs to see another site specific string, 128, which would have info like signaling server IP, port, plus a few other actions and be in the format of

Nortel-i2004-A,iii.iii.iii.iiipppp,aaa,rrr;iii.iii.iii.iiipppp,aaa,rrr.

Where “A” = the Hardware Revision of the i2004 Phone
“iii.iii.iii.iii” = the IP Address of the Call Server (S1 or S2)
“ppppp” = port number for the Call Server
“aaa” = the Action for the Server
“rrr” = the Retry Count for the Server

On your DHCP server you need to add in these site specific options via an ADD OPTION screen and make sure it is a string and make sure you add option 144 or 191 to the default VLAN subnet scope and option 128 to the non-default or VoIP scope.

Cautionary note - site specific option 144 is interpreted by some network decvices (HP JetDirect) as a TFTP server config file type option so use 191 instead.