Voice Lab – Adding a physical router
Posted by Josh on Thu 5 Mar 2009Categories: CCIE , Cisco , Cisco Routers , Cisco VOIP , Voice LAB - [25] Comments
In this tutorial, you will learn a couple ways to connect a physical router to your home phone line as part of your “virtual voice lab “. An all virtual voice lab would be ideal. However, real hardware is necessary for a more complete voice lab. I will be using a 2611XM for my home lab, but you can use just about any Cisco router with a couple fxs and fxo ports.
Several of you have contacted me over the past few months regarding the virtual voice lab and exactly how it should be done. Honestly, there is no right way. This tutorial series is meant to show you what is possible not exactly how it “must” be done. Have fun with your lab. If you don’t want two branches or you do not see a need for two different PCs for the branches, then customize it to the way you want it. It will help you learn.
This tutorial is in the same spirit. I will give you a few different ways you can connect your home phone line into your lab but seriously, I encourage you to make it your own and set it up the way that makes sense to you. Have fun with it. Change it. Break it. Fix it. Learn.
My Parts List
2611XM – Cisco 2600 Series Modular Access Routers
NM-2V – Understanding NM-1V and NM-2V Voice Network Modules
VIC-2FXS – Understanding Foreign Exchange Station (FXS) Voice Interface Cards
VIC-2FXO – Understanding Foreign Exchange Office (FXO) Voice Interface Cards
The 2611XM is an older router. The good … its cheaper. The bad … there are subtle differences compared to the ISRs used in the CCIE v3 lab topology. For example, transcoding is configured differently. Please pay attention to the differences if you are studying for your lab.
Here are a few things that become possible with the addition of a router that are not possible with an emulated router.
- voice port debugs
- Communicate with the outside world with h323, sip and mgcp gateway configs.
- T.37 fax to email
- Hardware conference bridging
- Transcoding
- Test BCAD for a home auto attendant.
Scenario #1 : Lab connected to the home
In a traditional home phone setup, a pair of wires extend from the telco to your house. This land line or POTS (plain old telephone system) line supplies dial-tone to all the phone jacks in your house. Below is a basic representation of a typical phone connected to a typical phone jack.
If you have a standard POTS line from the phone company and have no desire to incorporate your entire house into your lab, you should probably follow this scenario. Below is a representation of how your lab should look when you are finished following the steps below the drawing. Your router should be connected to the phone jack and the telephone should be connected to your router. If you do not have both FXS and FXO cards, just try to work with what you have.
- Find a phone jack close to your lab equipment.
- Unplug the analog phone from the wall jack
- Connect one of the router’s fxo ports to the wall Jack.
- Connect the analog phone to one of the router’s fxs ports.
- Configure the fxo voice port to send calls to extension 1000 with the ‘connection plar’ command.
voice-port 0/0
connection plar 1000 - Configure a dial-peer for extension 1000. The following pots dial-peer will send all calls for extension 1000 to port 1/0.
dial-peer voice 1 pots
destination-pattern 1000
port 1/0 - Attempt a call to your house. The analog phone should ring through your router.PLAR stands for ‘private-line automatic ringdown’. Some people also refer to this as the batphone setup. When a call comes in on the FXO port, it is automatically routed to the FXS port connected to the analog phone.
Scenario #2 : Home connected to the lab (voip provider)
The reason I named this scenario “Home Connected to the lab” is because the router is not receiving dial-tone from your house. Your house is receiving dial-tone from your router. This is how I have my house setup. This works best if you do not have dial-tone from the phone company. Only a voip provider.
I do not have a traditional land line from the Telco. I get dial-tone from an ATA provided by a voip provider. The cool thing about this setup is that I did not have to re-wire anything and I am able to provide dial-tone to my whole house from my router.
Eventhough the local phone company turned off dial-tone when I cancelled my service, all the jacks in the house are still connected to each other, so by connecting one jack in the house to an FXS port, all jacks have dial-tone. I learned this first by connecting my ATA to a phone jack before I started working on my home lab.
Here are the steps
- Unplug the analog handset from your VOIP ATA (analog terminal adapter)
- Connect the ATA to an FXO Port on your router
- Make sure you do not have dial-tone from another phone in the house.
- Connect the your router’s FXS port to the wall jack close to your lab. Now, check the other phone again. You should have dial-tone.
- Configure voice-ports and dial-peers to route calls from the FXO port to the FXS Ports. Voice Port 1/0 is the FXS port connected to the wall jack. Voice Port 1/1 is the FXS port connected to the analog handset. The ‘preference 1′ option tells the router to choose dial-peer voice 2 as the second option, because dial-peer voice 1 is configured with ‘preference 0′ by default.
voice-port 0/0
connection plar 1000dial-peer voice 1 pots
destination pattern 1000
port 1/0dial-peer voice 2 pots
destination-pattern 1000
preference 1
port 1/1
March 6th, 2009 at 1:04 am
Hi josh
I always visit this site , but this one is what i looking for. connect voice virtual labs to real routers.
March 6th, 2009 at 1:05 am
almost Forgot to say Thanks alot
March 6th, 2009 at 2:46 am
nice one Josh,I think I would love to try this with a PSTN line from a telco
March 8th, 2009 at 9:27 am
you always great josh. thank you for the information. i learn a lot because of you.
tenx..
March 8th, 2009 at 9:56 pm
josh can i have question. how about if i put DSL for 1 mbps only and don’t have static ip, it is possible to create a voip in home? to call IDD outside country. can you please post a configuration or diagram? i want to try it into my home lab.
thank you
March 12th, 2009 at 5:07 am
Apriyanto,
I’m am glad it helped.
Josh
March 12th, 2009 at 5:22 am
redhot,
I have plans for a tutorial on this in the future.
Josh
March 16th, 2009 at 9:35 pm
Nice one. What happens when you wan to achieve same with ADSL connection. You know how you have a splitter. i connected phone to fxo, i can make it work but there is noise and dropout when phone is in use. can you do a brief runown of that scenario. I belive its pretty common scenario. I need to try using diferent filter for noise i believe
March 24th, 2009 at 10:48 am
Josh,
You mentioned that you’re using a 2621xm with VIC-2FX0 and VIC-2FXS on a NM-2V. But you also mentioned using DSPs. How can you use DSPs in a 2621xm modular router when the NM-2V is taking up with only slot you have?
March 26th, 2009 at 11:30 am
How about a lab on using CCM and Dynamics?
April 8th, 2009 at 6:14 am
Hi Josh,
Ive been following your voice video’s from the start. I now have the 2621xm setup the same as you do. I only have 192/48 memory capacity and my IOS is taking so much i cannot get the basic CME files on. Have you or someone every tried extracting the tar, taking out some phones, files and repacked? I only need CME just long enough to get me through CCNAV then it can go
/Jon
April 12th, 2009 at 8:15 pm
Josh,
Great work this is awesome. I have been following all your tutorials. I have vonage so this will work out well.
Thanks,
Brian
April 19th, 2009 at 7:48 am
Ak,
I consider the pots line coming from a DSL splitter the same as a land line.
You should use scenario #1
Josh
April 19th, 2009 at 7:51 am
Jon,
I am having the same problem. I have tried using a more basic image in flash and then trying to boot to the advanced enterprise image via tftp but I have not had any luck yet.
I will probably end up purchasing more flash.
Josh
April 19th, 2009 at 7:52 am
Brian,
Great to hear! Good luck in your studies.
Josh
April 19th, 2009 at 8:05 am
Matthew,
The dsps needed are built-in on the NM-2v network module.
Here is a document.
http://www.cisco.com/en/US/products/hw/modules/ps2617/products_tech_note09186a0080094ac0.shtml
Josh
April 26th, 2009 at 5:03 am
Thanks for response Josh. Apparently changing filter resolved the issue. I got another issue. When i call my home from say a mobile phone the analog phone does ring but if i disconnect that call from my mobile the phone still keeps ringing which is kinda weird. i have to answer it (silence on pickup) else it just keeps ringing. Any ideas?
July 1st, 2009 at 12:40 pm
hi
I want to know if we can emulate dial up using virtual router? kindly tell me because i have to make an ISP as my FYP uing vertual routers in dynagen dynamips.
July 16th, 2009 at 8:38 am
HI ak76,
I have the same problem with calls coming in on an fxo port. plar is configured to send it to an ext but after the call hangs up the extension keeps ringing?
Any ideas
October 17th, 2009 at 4:20 pm
Hi Josh
i used a 2620XM ( Scenario 1#) with the NM-2V module and the FXO and FXS cards and an analog phone but it didn’t work.Is it possible that it needs more configuration at the FXO port, or at the FXS ports?I also made two other dial peers for the FXO port to forward calls calls to my PSTN and they work fine.But when someone tries to call me my phone doesn’t ring.What could be the problem?
December 19th, 2009 at 1:52 pm
hi Jon and Josh,
Me too had the same memory-requirement problem for CME. But I solved it. Here is the way to do it.
1. Extract the tar file using 7zip or winrar.
2. Open the extract. There will be a folder named Phone. Open it. In it, delete all folders except the one which contains the name of your ip phone as folder-name ( The folder “7940-7960″ in my case).
3. Repack the archieve to tar format. Now its size will be only around 4MB (in my case), which, the memory of the router can accommodate.
4. Copy the archieve to router.
Hope it helps.
And dear Josh,
Thanks a lot for setting up and maintaining this PRECIOUS site. The labs are simply amazing. Your work is inspiring and helping a lot of people. May God reward you with his blessings.
January 13th, 2010 at 1:34 am
ak76 & Stev,
The fxo disconnect is a commmon problem.
Take a look at this:
http://www.cisco.com/en/US/tech/tk652/tk653/technologies_tech_note09186a00800ae2d1.shtml
Josh
January 13th, 2010 at 1:36 am
Usman,
You would need a voip trunk. Most likely sip. There is not a way to emulate physical voice interfaces.
Josh
January 13th, 2010 at 1:41 am
athmpo,
I don’t think more configuration is necessary. Connection plar and a voip dial-peer are about as simple as it gets.
Josh
January 13th, 2010 at 1:42 am
Amal,
Thank you for sharing your experiences!
Josh