Michael McNamara

technology, networking, virtualization and IP telephony

DHCP Options (VoIP) Part 2

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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.

Where: “VLAN-A” Option 191 begins with this string for all Nortel IP phones.
“vvvv” The VLAN ID for the voice VLAN in decimal
Here’s an example if I were trying to assign the phones with a voice VLAN of 31;

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.

  1. The phone will boot up and make a DHCP request for option 191 in the Default VLAN of the port connecting the phone.
  2. If the phone receives a response to it’s request it will issue a DHCP Release of the address it received in Step 1.
  3. 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)
  4. 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.

With all that said we did leave out one very important piece of the pie… the network switch configuration. You’ll need to configure the VLAN and QoS settings manually depending on the switch vendor.

Cheers!

DHCP Options (VoIP)

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In this post I’d like to cover the DHCP options you’ll need to automatically configured the Nortel i2002/i2004 Internet Telephones as they boot. These DHCP options will actually work with any of Nortel’s Internet Telephones including the i2002/i2004/i2007/1120E/1140E and 1150E.

You’ll need to add a custom vendor DHCP option with a code of “128” as a string value. You should name this DHCP option as “Call Server Information”. The value of this DHCP option will use the following format;

Nortel-i2004-A,iii.iii.iii.iii:ppppp,aaa,rrr;iii.iii.iii.iii:ppppp,aaa,rrr.

Where the following values are;

  • “Nortel-i2004-A” = Option #128 begins with this string for all Nortel IP phone sets
  • “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

The IP Address must be separated from the port number by a colon (:). The parameters for the Primary (S1) and the Secondary (S2) Call Servers are separated by a semicolon (;). The string must end a period (.).

For this example, enter the following:

Nortel-i2004-A,10.1.1.10:4100,1,5;10.1.1.20:4100,1,5.

This would equate with the following values;

  • Call Server S1 = 10.1.1.10
  • Port S1= 4100
  • Action S1= 1
  • Retry S1= 5
  • Call Server S2 = 10.1.1.20
  • Port S2 = 4100
  • Action S2 = 1
  • Retry S2 = 5

You can use the vendor class of “Nortel-i2004-A” if you’d like to build different scopes within your DHCP server. A default scope for all general devices and then a specific scope for any device that requests the vendor class of “Nortel-i2004-A”.

Let me make this comment… if your DHCP server mistakenly returns a DHCP response that does NOT include DHCP Option 128 the IP phone will just sit at the “Starting DHCP…” prompt. You need to make sure that you return DHCP Option 128 in the DHCP response to the phone.

This all assumes that you’ve setup a DHCP relay on the Voice VLAN on the core ERS 8600 switch or whichever switch you might be using as the router for that VLAN.

I’ll review the basic configuration of the ERS 8600 (core) in a subsequent post as it applies to the example configuration I’ve laid out in the past few posts.

Please feel free to drop a line if you have questions.

Cheers!

Nortel i2002/i2004 Internet Telephone

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[ad name=”ad-articlebodysq”]We generally deploy just two phone models, the Nortel i2002 and the Nortel i2004. The phones support the exact same feature set, the only difference being the size of the display and the number of “keys” or appearances. The Nortel i2002 supports the following features;

Here’s a picture of the Nortel i2002 Internet Telephone.

  • 4×24 Character LCD
  • Headset Jack
  • Handsfree speaker phone
  • 802.3af PoE (Class 2)
  • Internal Switch (10/100Mbps)
  • XAS (Application Gateway) support

Here’s a picture of the Nortel i2004 Internet Telephone.

  • 8×24 Character LCD
  • Headset Jack
  • Handsfree speaker phone
  • 802.3af PoE (Class 2)
  • Internal Switch (10/100Mbps)
  • XAS (Application Gateway) support

You can see that both phones are fairly similar and they run the same software/firmware. We use a single CAT5e/CAT6 cable drop to connect the phone and then connect the end-user’s desktop/laptop to the PC port on the phone. We employ QoS to guarantee that the voice VLAN gets the appropriate priority and queuing over the data VLAN.

How do you get started?

I will outline how we configure the i2002/i2004 phones for LLDP (Link Layer Discovery Protocol / 802.1ab) and LLDP-MED for the voice VLAN assignment. We configure every phone with the same configuration throughout the enterprise. We rely on LLDP and DHCP to provision the phones with site specific information such as voice VLAN, IP address, Succession Call Server, etc.
You can of course statically configure all that information into the phone manually but then you’d need to visit the phone anytime you needed to make a change and if you had to replace a phone you’d need to re-program it to match the original settings (assuming you had them documented somewhere).

As of August 3, 2007 the phones are shipping with firmware 0604D31. This firmware does NOT support LLDP and will not have an option to enable LLDP. In order to properly deploy LLDP on the Nortel i2002/i2004 Internet telephones you’ll need to be running firmware 0604DBG or later. In order to upgrade the phone you’ll need to get it to connect to the Call Server (that means you’ll probably need to static the configuration through the phone). Once the phone connects to the Call Server it will automatically pull down the latest firmware that has been installed on the Call Server.

If you don’t have a PoE (Power over Ethernet) switch you’ll need to use a power supply to power the phone. As the phone is booting you’ll need to strike the four soft buttons at the bottom of the display window while the text “Nortel Networks” is being displayed. This will allow you to confirm that the phone is configured properly from the factory.

You should configure the i2002/i2004 IP phone as follows; (depending on what version of firmware is installed on the phone you might not see all the options below)

  • EAP Enable? [1=Y, 0=N]: 0 (Default – no EAP authentication)
  • LLDP Enable? [1=Y, 0=N]: 1 (we are going to need LLDP)
  • DHCP? [0-No, 1-Yes]: 1 (we are going to need DHCP)
  • DHCP: 0-Full, 1-Partial: 0 (we want to get a full DHCP response)
  • Speed[0-A,1-10,2-100]: 0 (Auto negotiation)
  • Cfg XAS? [0-No, 1-Yes]: 0 (Default – we don’t use XAS)
  • Voice 802.1Q[0-N,1-Y]: 1 (Default – mark voice VLAN pakcets with 802.1Q tags)
  • Voice VLAN? [0-N, 1-Y]: 1 (we want a Voice VLAN since we’ll be attaching a PC to the PC port)
  • VLAN Cfg? 0- Auto, 1-Man: 0 (Automatically configure the Voice VLAN)
  • LLCP MED? 0-No, 1-Yes: 1 (Voice VLAN will be configured using LLDP-MED)
  • LANFILTER? [0-No, 1-Yes]: 1 (filter Voice VLAN packets from the PC port)
  • Ctrl pBits[0-7,8-Au]: 8
  • Media pBits[0-7,8-Au]: 8
  • PC Port? [0-OFF, 1-ON]: 1 (Default – leave PC port enabled)
  • Speed[0-A,1-10,2-100]: 0 (Default – leave Autonegotiation enabled on PC port)
  • Data 802.1Q[0-N,1-Y]:1 (Default – mark data VLAN packets with 802.1Q tags)
  • DATA VLAN? [0-N, 1-Y]: 0 (Default – we’re going to use the PVID on the switch port)
  • Data pBits[0-7,8-Au]:8
  • PCUntagAll? 0-No, 1-Yes: 0
  • DUPLEX [0-AUTO, 1-FULL]: 0
  • GARP Ignore? [0-No, 1-Yes]: 0
  • PSK SRTP? [0-No, 1-Yes]: 0 (Default – you can encrypt the RTP stream if necessary)

If everything has been setup and configured properly (including the Call Server, network switch, DHCP server, etc) the phone will boot and will prompt you for a “Node Number” and “TN”.

I’ve jumped the gun by telling you how to configure the phone before configuring all the back-end equipment, including the Nortel Ethernet Routing Switch 5520 PwR and the DHCP server. In my next installment I’ll cover how to configure the Nortel Ethernet Routing Switch 5520 PwR and what you’ll need to configure in your DHCP server.

Troubleshooting

If the phone hangs with “Starting DHCP…” on the display for more than 60 seconds you’ll need to start troubleshooting. You’ll need to confirm that the phone is configured properly and you’ll need to confirm that it’s grabbing the proper IP address from the DHCP server. Just remember that the MAC address can be found on the back of the phone.

Cheers!

Voice Over IP with Nortel

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[ad name=”ad-articlebodysq”]I’d like to take some time to discuss Voice over IP and share some of my real world experiences with the technology. I should note to everyone that my experiences with VoIP are strictly limited to Nortel equipment. While I’m somewhat knowledgeable about Cisco Callmanager (mostly thanks to my cousin who maintains the Call Center for a large automotive manufacturer) my personal experiences are limited to Nortel.

We’ve been using VoIP for almost the past 6 years with very good success. Our first forey into VoIP was using Nortel’s IP Line ITG (Internet Telephony Gateway) with a Nortel Meridian 1 Option 61C switch. We had Nortel’s first generation i2004 phones (the purple “barney” phones as we fondly referred to them). A few hardware and software upgrades later that same system is now known as Nortel’s Succession 4.5 1000M Call Server. We’ve been running IP Trunks (H.323) between 5 different Succession 4.5 1000M Call Servers for well over 4 years now with great success. We’ve only just in the past year started really rolling out VoIP to the desktop where it makes sense (example; new construction).

What do you need to run VoIP with Nortel?

These days you can run VoIP on all sorts of different platforms from small office (BCM 50) to very large multi-site enterprises (CS 2100). I’ll describe the equipment that I’m currently using;

  • Nortel Succession 4.5 Call Server 1000M
  • Nortel Succession 4.5 Signaling Server (two for high availability)
  • Nortel Succession Voice Gateway Media Cards (five for high availability and capacity)
  • Nortel Succession Internet License (Incremental Software Management – ISM)

You’ll need a phone of course;

You’ll also need some back-end network electronics/switches;

And to make life easy you’ll also need a DHCP server which you can configure with custom vendor DHCP options.

If your a data person you’re most likely going to need some help from either a voice/telecom person or voice reseller. Likewise if your a voice/telecom person you’re going to need some help from either a data person or a data reseller. I happen to be a data person that has learned the voice/telecom side of things from my years of exposure and from the failure of several voice resellers, nothing like picking up the books and learning something new.

Since I’m a data person I’m going to focus on the actual network electronics and the phone configuration. In the past year I’ve deployed more than 250 IP phones at more than 5 locations. That number doesn’t include the 100 or so Nortel 2211 Wireless Internet Telephones which we’ll discuss at some later date.

I currently have a Nortel 1140E (pictured right) on my desk at work along with a Nortel i2007 on my desk at home (Nortel 1150 VPN Router with Branch Office Tunnel – BOT) and an i2050 software IP phone on my laptop with a USB headset adapter that really makes the phone work.

We recently built a health center with 140+ IP phones which are all connecting to a hospital that is more than 17 miles away. We built a 10GB Wide Area Network over dark fiber utilizing Nortel Ethernet Routing Switch 8600s with 8683XLR cards and 10GBase-ER/EW XFP GBICs. We also installed and provisioned a Nortel 1000B Branch Office at the health center to provide a failover solution should the IP phones get disconnected from the Main Office Call Server. This site has been live for the past 5 months now and I’m very satisfied with the result of our work and efforts. The solution is very reliable and thanks to the design of the data network we’ve yet to experience an unscheduled outage.

Stay tuned for more…

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