Bridging and Routing on the same device 1

[hyperrad]

Hey all, I need some assistance on bridging / routing on the same router.

I've got a single port for VoIP that must be bridged and another single port for Data that must be routed. These both will be going over serial T1 links to two seperate facilities.

Any tips or sample code would be greatly appreciated!

 

[lambent]

Is there any reason to use bridging rather than routing?

 

[hyperrad]

Yes, we have a Nortel BCM at our main facility that handles VoIP. Instead of spending $20G a facility, we'd like to bridge the VoIP and route the other data.

 

[jneiberger]

I still don't see why this traffic has to be bridged. Is there a technical reason why the BCM would require IP phones to be one the same LAN or subnet?

 

[hyperrad]

The traffic has to be bridged because we are about to have two sites on different subnets. The BCM will not handle routing without two more devices at the other facilities for a pricey nominal figure. So the cheaper and more logical method to save money and not waste assets would be to bridge 2.x traffic to all facilities and route the other facilities' subnets.

This is a fairly large network also so routing is ideal to cut down on broadcast traffic. Remember also, we're using 1.5M links between the facilities. A straight bridge would and is dragging the line down with the added VoIP traffic. However, after we route the data we'll be utilizing the T1 for voice and replication only.

 

[jneiberger]

So, at your main site with the BCM, all phones have to be on the same LAN as the BCM?

I think having a BCM is one of your problems. ;-) I'd dump Nortel and go with Mitel/Avaya/Cisco if I were you. In a smaller environment like this I think Cisco and Mitel would be able to help you out. Avaya might be too expensive.

Anyway, back to the problem at hand. You have a need to route regular traffic between your sites but to bridge your voice traffic so that you have a single voice VLAN/subnet over your WAN and at your main site. Is that correct?

 

[hyperrad]

Yes, that is correct. Route data, bridge voice over a single T1 link to each facility using Cisco 1800 series routers.

 

[jneiberger]

This is going to be a tough one. Are you using point-to-point T1 circuits? Are you running HDLC at L2 or something else like PPP or frame relay? It may be simpler just to use NAT at your main site to make your remote phones appear local.

Can you confirm that this requirement also exists at your main site? Do all IP phones in your network have to reside in the same subnet? I'm still having a hard time wrapping my head around this requirement. Why does the BCM care?

 

[hyperrad]

We're using megalink point-to-point T1 circuits running on HDLC. Unfortunately, they must be in the same subnet as the BCM - this is per the vendor (however we may be misinformed).

I'm open to any suggestions of other methods that are logical.

 

[Maverick8673]

just out of curiosity what routing protocol are you using?
BCM's have RIP as an option. I have never heard of someone telling anyone to bridge voice, that is such a high priority packet bridging it will sound like crap. I used to have only one BCM at a location and using ptp t's was able to get ip clients on the bcm and use ip sets at the other end, but this ofcourse makes you have to have the network up all the time. QoS and policy maping may be a way to go too.

 

[hyperrad]

Nothing at the moment due to this issue right now. Before, I was using EIGRP.

Do you know if the BCMs have Rip v1 or v2?

If I used Rip... I'd prefer to use MD5 hashes from the source to add protection. I doubt the BCM has this option "not at work or I'd check".

I'm starting to feel our vendor needs to learn their product so... perhaps I should investigate the full features of the BCM.

 

[Maverick8673]

This is a basic sheet it has RIP V/2

http://www.sasktel.com/business_works/business_brochures/bcm/bcm_data_apps.pdf

I agree with you on the vendor issue, some just want to sell the product, but I have been in your shoes, although I have 7 bcm's and one option 11 all networked with cisco routers using EIGRP at each site using the built in QoS on the bcm, layer 3/4 switches, frame relay, and QoS on the routers. Sites without the BCM i use i2004/2050 phones connected to the BCM's via ip client, and to the closest BCM IE:bcm in NC, ip phones in SC use the NC BCM. Caveat, Any issues with the BCM in NC or the network then the IP phones will go up and down, but I able for the exec's phones, to program 2 BCM locations incase one goes down it can use the other, just something I found useful.

 

[hyperrad]

When you say you program the i2004 phones via the IP client. Explain this... Are you talking about the web interface or are you talking about another application I may not be familiar with?

Do you use static addressing for the phones or DHCP?

I appreciate all this advice on the system. I'm fairly new to the field, they fired the old Systems Administrator, and elevated me to the position since I hold numerous certifications.

Thanks!

 

[jneiberger]

Although I don't know much at all about the BCM, I think you have been misinformed about the need for all phones to be on the same IP subnet. I can think of no technical reason why this would be the case. Then again, Nortel has made some "interesting" design decisions in the past so I guess I wouldn't be overly shocked. You should post this question over on the BCM forum.

In fact, if I think about it in a few minutes I'll do it for you.

 

[jneiberger]

By the way, which model of BCM is this?

 

[hyperrad]

I believe it's the BCM 400 unit.

 

[Maverick8673]

Ya, some of this post may need to go to the BCM forum lol, but in todays age these forums should be one and the same, everything is going that way after all

 

[jneiberger]

I've posted this question to the BCM forum and the initial response is that the reseller is full of it and there is no need to put all IP phones on the same IP subnet.

hyperrad, what was the reason they gave when they told you to put all IP phones on the same IP subnet?

 

[hyperrad]

Basically, they said that it had to be bridged or that it could be routed. They said we should bridge it. I asked about Nortel's gateway because since I read about it on their website and asked if it was an option. Apparently... they didn't know much about it.