Building cheapo VOICE/DATA home Cisco LAN (need advice)

fonestar1978

Merry Xmas all!

I am a tech and a CCENT but am just starting to play with the Cisco stuff again and I'm having fun with it so far. With this stuff for me, learning is doing. I don't know anyone who would study CCNA/CCNP never use it and then recall all IOS commands five years down the road so......

I am building a cheapo VOICE/DATA Cisco LAN. I use "PBX in a Flash" running on a prehistoric Pentium II headless server. I will only have two or three hard phones (using VoIP adapters) up to this.

I am purchasing a Cisco 2621XM and currently have two Catalyst 2950 switches. One FastEthernet port of the 2621XM will be for the DATA vlan going to one switch the other FastEthernet port will be going to the other 2950 dedicated for VOICE. Two separate networks, two interfaces, two vlans. The 2621XM will also have a NM-1FE facing WAN through a cable modem which goes through a signal amp/splitter.

I guess my main questions are:

I have been told ALL 26XX series only support NM-1E's and not NM-1FE's is this true? Even XM's?

Is the 2621XM going to be a good enough platform for VoIP? CPU? Memory?

Save for a 2651XM instead?

I am just learning to configure QoS on switches. How to prioritize on the 2621XM?

How to optimize bandwidth on the entire setup?

What are the best VoIP converters for regular telephones (I cannot afford Cisco IP phones)?

Do these dongles support frame tagging? Do I have to set the switchports being used for the phones as trunks?

Any good tutorials?


Thank-you for any advice. I'm hoping this will be educational, practical and hopefully under $1,000 when all is said and done.

mikej412

fonestar1978 wrote: »

I have been told ALL 26XX series only support NM-1E's and not NM-1FE's is this true? Even XM's?

Right, they do not support the NM-1FE modules.

But rumor has it that there have been some 2600 images where the NM-1FE did work.... Good Luck finding one. Not sure if any of the image names have been posted -- might be worth some time searching the Cisco forum for various keywords.

fonestar1978 wrote: »

Is the 2621XM going to be a good enough platform for VoIP? CPU? Memory?

What are you planning to do?

I've got a couple of 2650 routers with NM-2V modules and VIC-2FXS and VIC-2FXO cards -- and they work find in my lab. Either one could run my home analog phones if I plugged my phone line into an FXO port and my home loop into an FXS port.

fonestar1978 wrote: »

Save for a 2651XM instead?

I've got an AIM-CUE for voice mail in my 2650XM, Call Manager Express 4.x, and an NM-HDV module with 5 PVDMs installed and a VWIC-2MFT-T1 card.

fonestar1978 wrote: »

I am just learning to configure QoS on switches. How to prioritize on the 2621XM?

How to optimize bandwidth on the entire setup?

In the simplest case, you can try the auto qos macro.

You can check out the QoS section of the Configuration Guide for your switch(es) on the Cisco Web Site.

For your router(s), check out the Cisco IOS Quality of Service Solutions Configuration Guide for your IOS version(s).

Here's the one for 12.4 -- Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.4 [Cisco IOS Software Releases 12.4 Mainline] - Cisco Systems

You can also find some QoS links in the CCVP Forum FAQ.

fonestar1978 wrote: »

What are the best VoIP converters for regular telephones (I cannot afford Cisco IP phones)?

You can plug your home loop into an FXS port.

You can (wire and) plug individual analog phones into individual FXS ports.

If you use a non-Cisco VoIP adapter, read that vendor's docs and then try creating a Voip Dial Peer on your Cisco Voice Router and try to access it.

mikem2te

But rumor has it that there have been some 2600 images where the NM-1FE did work.... Good Luck finding one. Not sure if any of the image names have been posted -- might be worth some time searching the Cisco forum for various keywords.

I have read this also but I believe the internal bus is speed limited so you probably will sacrifice some of your cable internet speed. Why not use one of the internal FE ports on the 2621XM for the internet and the other configured as a 'router on a stick' with the two vlans (voice and data) connected to a trunk port on your switch??

What are the best VoIP converters for regular telephones (I cannot afford Cisco IP phones)?

Have a look at Cisco ATA186, they have two analogue voice ports for conventional telephones. Can be found cheap on ebay. You can install fxs ports into the router but you will need to get some PVDM/DSPs installed in the router such as NM-2V which include DSPs to run two fxo/fxs cards.

Do these dongles support frame tagging? Do I have to set the switchports being used for the phones as trunks?

Typically when using Cisco phones & ATA's, you would configure the switchports as access ports but assign a data vlan and a voice vlan. Most Cisco phones have two ethernet ports, one to connect to the switch and the other to allow connecting a computer in a daisy chained fashion. This is a boon in corporate installations as it allows one ethernet cable to run both a computer and phone but each with it's own vlan. You would use something like-
switchport mode access
switchport access vlan 1
switchport voice vlan 20

Have a look at this, may help-
Group Study: Good Explanation of the Voice VLAN CCIE Pursuit Blog

fonestar1978

Yes, maybe one FastEthernet port to WAN and the other as 'router on a stick' may be the way to go as opposed to going to a more expensive platform like the 2800.

Question though, my understanding is that it is better to have VOICE and DATA vlans configured with their own dedicated FastEthernet port as opposed to a subinterface on a router, through a trunk or not? Is this not right?

Seeing as how I just using an Asterisk server, which will be on the VOICE vlan I don't think I have any use for an FXO card or PVDM's do I?


Thank you again!

mikem2te

fonestar1978 wrote: »

Yes, maybe one FastEthernet port to WAN and the other as 'router on a stick' may be the way to go as opposed to going to a more expensive platform like the 2800.

Question though, my understanding is that it is better to have VOICE and DATA vlans configured with their own dedicated FastEthernet port as opposed to a subinterface on a router, through a trunk or not? Is this not right?

Having separate router interfaces would be ideal but in reality I think there is no real benefit. The routers processor / packets per second rating will be the weakest link rather than the interface speed so having dedicated interfaces will probably be overkill. QoS should probably sort out any other delays. But then I like a challenge and getting QoS configured will be a good challenge. Not even sure how much data would hit the router anyway as I guess the RTP streams will between devices rather than via the router.

When I was doing my voice labs, I used router sub interfaces connected to a trunk port on my switch and had no problems.

Seeing as how I just using an Asterisk server, which will be on the VOICE vlan I don't think I have any use for an FXO card or PVDM's do I?

Probably not. PVDM are usually only used to interface PSTN/POTS cards (fxo, pri isdn etc). If you need some fxs ports look for the ATA, I like them and you don't need to install any PVDM's in the router to get them to work. PVDMs do a few other things as well like music on hold, conference calls, transcoding etc which may be nice to have a play with but I don't know what you will need to add to a 2600xm to make it work, probably a NM-HDV with som PVDMs on board.

Oh, if you intend to join the 2600xm to the asterisk server, never tried it but there may be some transcoding required but I guess there will be a common codec availble to both sysytems.

fonestar1978

Thanks to everyone for the advice, this has been very informative....

One last question though, seeing as how I am going with one FastEthernet port 'router on a stick' configuration do I even need a second Catalyst 2950 in this network now?

I mean, could I have two vlans (VOICE/DATA) on one Catalyst 2950? Say, dedicate fa0/1 - 12 to vlan VOICE and fa0/12 - 24 to vlan DATA and each to a separate sub-interface on the 2621XM? I would imagine having the frames go through one switch as opposed to two via a trunk will have a small but real effect on latency?

Thanks again!

mikem2te

fonestar1978 wrote: »

One last question though, seeing as how I am going with one FastEthernet port 'router on a stick' configuration do I even need a second Catalyst 2950 in this network now?

One is fine.

fonestar1978 wrote: »

I mean, could I have two vlans (VOICE/DATA) on one Catalyst 2950? Say, dedicate fa0/1 - 12 to vlan VOICE and fa0/12 - 24 to vlan DATA and each to a separate sub-interface on the 2621XM?

Yeah, use something like this on the 2950. This is from memory so I could have got something wrong!!!

vlan 1
name Data

vlan 20
name Voice

interface range f0/1 - 12
switchport mode access
switchport access vlan 1

interface range f0/13 - 23
switchport mode access
switchport access vlan 20

interface f24
switchport trunk encapsulation dot1q
switchport mode trunk

Ports 1-12 will de for Data, 13-23 for Voice and port 24 configured as a trunk goiing to a FE port on the router.

fonestar1978 wrote: »

I would imagine having the frames go through one switch as opposed to two via a trunk will have a small but real effect on latency?

Very small effect on latency less than 1ms. They recommend a letency of less than 150ms for voice.