sundance-communications.com/forum Forums TDM Business Telephone Systems Avaya - Lucent Telephones & Systems IP500 6.0 DHCP

I am going to be installing an IP500v2 6.0 with approx. 45 1600 series IP phones, and 8 9620's. Currently they have a DHCP server. What are the DHCP option numbers that need to be set up? We are going to be putting the IP phones on a different subnet than the computers. Is it better to let the current DHCP server hand out the IP's for the IP phones as well?

Will you be routing between the subnets? For example say you have subnet 10.10.1.1 and 10.10.1.2 and you place the phons in .2 but the DHCP server is in .1 you will not receive DHCP in that scenario. Unless you at bare minimum route between the subnets it won't work. Even if you do you will want a DHCP server on each subnet. A DHCP server can provide IP addresses to clients spanning multiple subnets if the router that separates them can act as an RFC 1542(BOOTP) relay agent. If the router cannot function as relay agent, each subnet that has DHCP clients requires a DHCP server.

Assuming you are using a Windows DHCP server you'll ant to read this:

https://www.ipofficeassistance.com/HOWTO_DHCP_IP_Phones.html

Well you learn something every day. I just did an IP500 install yesterday and I was delighted to see that it has a built in DHCP server. You can configure it to only deliver addresses to IP phones. Also, we installed a Netvanta 1238 POE switch which niftily passes IP traffic on layer 2 rather than routing it. So we were able to run some computers off the switch built into the phones and not have to do anything at all with VLAN routing etc.

Pardon my asking but how in the world did you get to install IPO without knowing that it can act as a dhcp? According to Avaya you cant touch the system without being certified on it. I have a feeling your customers will be very unhappy with IPOffice.

How? I hired a guy who does it for a living. That seemed like the quickest solution to me. :shrug:

Vit, keep your insults to yourself and don't post them on my thread.

Fantastic. You "installed a Netvanta 1238 POE switch which niftily passes IP traffic on layer 2 rather than routing it." By definition a network switch passes traffic on layer 2 rather than routing it.

I am also intrigued by this observation: "For example say you have subnet 10.10.1.1 and 10.10.1.2 ..."

Fantastic. You "installed a Netvanta 1238 POE switch which niftily passes IP traffic on layer 2 rather than routing it." By definition a network switch passes traffic on layer 2 rather than routing it.

I am also intrigued by this observation: "For example say you have subnet 10.10.1.1 and 10.10.1.2 ..."

Oops, that was a brain fart. My bad. 10.1.1.1 and 10.1.2.1 and yes layer two switches packets rather than route them like a traditional router would. That was what I was telling the person, how layer 2 works. But that is the problem since that makes the DHCP server on the LAN side able to handle requests from the VOIP side. The best solution in a VLAN config is to enable routing but don't static route anything. That effectively turns off switching between those subnets assuming your VLAN switch will do this - but surprise, not all will! The Netvantas won't. Of course you lose the ability to run a computer off the phone's internal swicth unless they are all on the same net.

I would have gone HP Procurve 2610-48/PWR like I have used in the past but I did not put the sales order together for this, I was just brought in to make it happen. The Netvantas are great but best standalone not VLAN.

I'll defer any day to the phone knowledge here but I have two and a half decades of managing networks.

And the customer was very pleased indeed with the IP500. The cutover was seamless.

So why put the phones and computers on separate subnets? What is the advantage of that?