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DHCP, VLAN setting, IP Addressing Question

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Apexis

Technical User
Sep 29, 2005
65
US
I came up with a setup, so let me know your thoughts.

We have four offices, each with an IPO, all conntected via an MPLS network (basically like frame-relay, full T1 port speed) with a centralized voicemail pro server with the manager/tftp installed on the windows 2003 server as well.

Each local network has two VLAN's. VLAN1 is our data network and VLAN2 is our VOIP network. I've implemented full 802.1Q on our Dell 3448P switches at each office. The Dell switches basically look for the VLAN tags and if they're not present, they default the packets to VLAN1 (data network).

Note: We don't want to hardcode each port for either VLAN since we are plugging PCs into the data ports of the 5620's. Right now everything works just fine with static IP addressing for testing purposes but now we want to move to DHCP since the static IP addressing will get blown away with future phone updates.

Next step, setup DHCP:

So I setup a DHCP server on our centerlaized server with 4 DHCP scopes (server is hard coded to VLAN2 at site A). I've setup the DHCP option 176 as follows (of course each DHCP scope would have a different entry for the MCIPADD to their local IPO however the rest would be the same):

MCIPADD=172.16.11.51,MCPORT=1719,TFTPSRVR=172.16.21.10,VLANTEST=0

The routers at each site have DHCP relay enabled for the VLAN2's to route to the centralized server at site A for DHCP requests.

Now for the million dollar question since when a new phone boots up and sends out a DHCP request, the phone is defaulted to our data network on VLAN1 and will recieve a IP addy on our data network which we don't want.

One work-around I came up with (and I'm not sure if it would work) is to hard code a port on our switches at each site to VLAN2 for new phone setups and power the phone up for the first time on that port so that it would get a DHCP addy on VLAN2 (local router would forward the DHCP request for the local VLAN2 across our network to the centralized server on VLAN2 at site A) and then grab the 46xxsettings.txt file which would contain the following:

################ VLAN SETTINGS ######################################
SET L2Q 1
SET L2QVLAN 2
SET VLANTEST 0
#####################################################################

This would set the phone for 802.1Q framing, set the VLAN ID to VLAN2 and to never have the phone default to VLAN0.

If this would work, would the phones keep the VLAN settings after a reboot, powerloss or phone software upgrade?

What can I say...THANKS for everyone's help.

Rob
 
When you put the new phone on, program it's VLAN on the phone and you should be good to go. You can leave everything else as default, but by hardcoding the VLAN into the phone, it knows where to look for the proper information then.
 
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