In a previous article we reviewed how to configure a Nortel Ethernet Routing Switch 5520 using ADAC/LLDP (802.1ab) so a Nortel Internet Telephone could discover the voice VLAN ID automatically without manually configuration of the phone.
If you don't have a switch that supports ADAC/LLDP you can still utilize automatic VLAN assignment using DHCP. I've actually used this method (before Nortel supported LLDP) and it works well but can sometimes be difficult to troubleshoot.
You'll need to configure DHCP option 191 (string) with the following syntax;
VLAN-A:vvvv.Here's an example if I were trying to assign the phones with a voice VLAN of 31;
Where: "VLAN-A" Option 191 begins with this string for all Nortel IP phones.
"vvvv" The VLAN ID for the voice VLAN in decimal
VLAN-A:31.There must be a colon (:) seperating the VLAN-A from the VLAN ID. The string must also end in a period. It may be necessary, depending on your DHCP server, to enclose the enter string in quotation marks.
How does it actually work?
With the phone and DHCP server configured properly here's how it will work.
- The phone will boot up and make a DHCP request for option 191 in the Default VLAN of the port connecting the phone.
- If the phone receives a response to it's request it will issue a DHCP Release of the address it received in Step 1.
- The phone will make a second DHCP request in the VLAN that was returned in option 191. The phone will be requesting DHCP option 128 from the DHCP server, this will include the Call Server information. (Note: if you use a sniffer you will see that the DHCP packets will have an 802.1q header with the appropriate VLAN ID)
- The phone will connect to the Call Server specified in DHCP option 128 and will prompt the user for the Node ID and TN information.
Cheers!
9 comments:
I'm currently doing such a setup for a client using PP8610, edge ERS55xx switches and Nortel i2004 phones. I have been struggling with the ADAC/mac issues but hopefully the latest SW 5.1.0.0.1.4 will help. This series you have done are really appreciated. I think you mention somewhere that the PassPort need further configuration. Is that correct ?
Thx.
Kenneth
I am curious. The manual for the 1140e does talk about this technique for dhcp configuration. However, it says that you can pick from a list of option numbers including 128 for the first dhcp request. Can you use option 128 on the default vlan and still have it work?
Hi Kenneth,
You would need to have a core switch (such as an ERS 8600 or 5500) setup for Layer 3 switching (routing). ADAC is broken in anything less than 5.0.6.26. In v5.1 software we supposedly no longer need to maintain the MAC address list within ADAC, since the switch now uses LLDP to determine if there is a Nortel IP phone attached to the port.
Cheers!
Hi Prophet001,
You can use DHCP option 128 without using DHCP option 191. They are independent of each other. So you could most definitely just use DHCP option 128 to assign the phone an IP address and the proper CS1000 information while keeping everything in the default VLAN.
Cheers!
Can you push out TN and node information to the handset so the user doesn not have to enter that in?
I've got lldp-med and dhcp pushing everything else, thanks to your helpful blog... :)
I don't believe you can automate disseminating the node number and/or TN information with any of Nortel's Internet Telephones.
The information must be programmed manually the first time the phone is installed. The Nortel phones will store (NVRAM) the Node and TN information so that the end-users will not need to enter anything on subsequent reboots.
This isn't as big a problem as it might appear and/or sound. I've staged up to 250 Nortel i2002/i2004 phones prior to their final physical installation. I used the staging process to upgrade the phones to 0604DBG (required for LLDP-MED), to configure the phone settings (enable LLDP, enable Voice VLAN, enable LLDP-MED) and to program the node and TN information. I was then able to label each box (phone) and leave it's placement and installation to a non-technical team.
Cheers!
Hello, we are trying to use a BCM 400, BES 1020's, and 1140e phones. The BES's have some limitations and we are trying to find workarounds to automate the phone setup process. We can only do egress tagging on the ports. We have a voice and data vlan. We have tried to use option 191 to assign the vvlan but it does not seem to work. Option 128 does work. The issue is with both vlan's on a port the BES will not allow a phone to pull dhcp so we use lldp and it works. Can you use lldp and option 191 at the same time? or is it negated. Thanks.
Hi,
I don't believe the BES switch supports LLDP-MED, which is what you actually need for the switch to "inform" the phone which VLAN ID to use for the voice VLAN. At this time the only switch that supports this feature is the Ethernet Routing Switch 5520. The upcoming release of v5.1 for the Ethernet Routing Switch 4500 Series will also support LLDP-MED.
So to answer your question you really shouldn't need to use both LLDP-MED and DHCP Option 191 at the same time. If you actually configure the IP phone for LLDP-MED it will ignore DHCP Option 191.
Cheers!
The Nortel 1100 series phones via TFTP can assign the node and TN automatically in the lastest firmware UniStim 3.0. In fact, all parameters can be including all phone settings, volume, backlight, etc.
Hello,
You are correct. Every since release 2.3 (latest release that just hit the streets is 3.0) you can configure "almost all" the options via DHCP. There are obviously a few options you can't still configure via DHCP because the phone wouldn't be able to get a DHCP response.
You can read my post entitled "Nortel IP Phones - UNIStim release v2.3" for a list of all the DHCP options.
Thanks for the comment!
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