Can I have Call Manager setup for Branch offices via ISDN line ?

I have Head Office (HO) and 50 Branch offices, at the moment Call manager is configured only in HO, but I want to integrate the branch offices and want to deploy the cisco IP phones on each site. I know to integrate them via Data network (MPLS, DSL or other internet connection), but I have no idea how to connect all the branch offices through ISDN line, as we have ISDN calls free and I want all 50 sites phone communicate and get registered to the Call Manager. I want to setup this like its been setup via Data Network!

Reply will be appreciated.

Thanks
superluditeAsked:
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superluditeConnect With a Mentor Author Commented:
Actually we have changed the installation plan, we are going to register all IP phones via DSL line, but we want to configure the call manager for the branch offices to have separate groups and each group have their own extensions e.g I have CM in Head office and I want to connect the branch offices,but I want each branch office should have their extensions. e.g Branch A (200,201,202,..up to 2010) and Branch B extensions are the same (200,201,202..upto 2010) and same up to 50 sites ?

And each branch should not call the other branch office through internal extension,  if they want then they should call by press 9 and outside PSTN numbers.

Any help will be appreciated.

Thanks
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harbor235Commented:


So if you buy a MPLS product that provides L3vpns or L2vpns you can have IP connectivity back to the HO.
Why are you using ISDN, if ISDN is what your provider uses to extend you connectivity to your branch offices then thats fine, why not go for a ethernet or other higher bandwidth local loop product?

AS long as you have IP connectivity back to the HO this is not a problem. I asusme the MPLS provider will provide you the proper COS/QOS for a good call experience.

harbor235 ;}
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superluditeAuthor Commented:
No we are not going to buy MPLS connection or any other connection, we do have DSL and E1 connection to the Head Office!  and we do have internet connection to the branch office's as well, but slow speed! we do have ISDN connections to the branch offices free of cost!

How to connect the branch offices to the Call manager via ISDN link and it should always use ISDN line to dial internal extension as well as external pstn numbers.

Thanks
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harbor235Commented:


Well if you have conenctions already established and working then all your doing is accessing the call manager via IP, I m not sure what the problem is, if you have IP conenctivity to the HO site where the call manager resides then you just configure your phones with the proper IPS assoicated with  the correct voice vlan and you rotue the traffic to the CUCM. Since the call manager is not local you will need to provide local DHCP and tftp services, you could also use helper addresses to froward them to your HO site. However, with that many sites and potential phones I would try to distribute the load.

harbor235 ;}
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superluditeAuthor Commented:
Thanks for your reply, Well there is no problem , I know how to setup the regions and stuff for the branch offices through Data network, but now I have ISDN line in all my branch offices, we use this ISDN for visa terminal machine, but I want to use the same ISDN for voice communication. I want to know step by step solution. e.g

CM---->cisco2811---->Internet----->to-the-branch-site-----2811
                    |
                    |________ISDN-network________________2811______switch____IP-Phone

we do not want to use DSL (Internet line) for voice communication from the branch sites to the HO. In the above figure, I want the remote IP-Phones to be registerd through the ISDN line? All the calls to the CM should be via ISDN? For me it is a bit confusing !

Thanks

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harbor235Commented:


aah, I see now, sorry, I do not know that aspect of it, what I do know is each call consumes about 9k of traffic so you will need to assess whether you will have enough available BW.

grblades may be the guy to help you,

harbor235 ;]
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superluditeAuthor Commented:
Okay thanks, but how to contact grblades ?
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harbor235Commented:


I sent him an email and a link to your question.


harbor235 ;}
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superluditeAuthor Commented:
Thanks harbor235!

Will wait for his reply?

Thanks
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grbladesCommented:
I am not sure how much help I can be but I will give it a go :)

As far as the phones are concerned they will get an IP address from the local branch office DHCP server. Their configuration will be to connect and register with the CM server at the HQ.

On the router at the branch office you will need to configure policy based routing so that by default traffic goes out to the internet but any traffic destined to the CM server will be sent out over the ISDN line.
You will need to do a similar thing for the router in the HQ.
It can become more difficult when telephone call audio is switch directly between handsets as then the audio is between both handsets directly (This is the case for SIP but iy may be different or configurable for CM).
Having the handsets on different VLANS at each site would help make the router configuration easier but it is not a simple thing to do.

I am assuming the ISDN is already being used for another task.
An alternative if you have a free ISDN line is to have the phones on separate VLANS and have them set with a different default gateway to the normal pc's. This different default gateway will send all traffic it gets over the ISDN to the HQ. If only the phones have this different default gateway set it makes it much simpler.
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superluditeAuthor Commented:
Before I go to more complex situation, I just want to know that we use ISDN line for Phone and DSL for Data, but we don't want to use our DSL line for IP Phones, we want ISDN to be used like (DSL) between HQ and branch offices. I never seen any company used ISDN line for IP Phones, (Apart from backup line or SRST), but my boss want the ISDN to be used for primary line.

I am not sure whether I would get the same configuration and call control like we get in IP enviroment ?

Thanks
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grbladesCommented:
VoIP is just IP data so the configuration will be pretty much the same. Using a high compression codec you will be able to get two telephone conversations down a single ISDN channel (bearing in mind an IDSN circuit normally has 2 channels).

Dont run a VPN over the ISDN though. VoIP packets are very small and having them stored within a VPN packet will increase their size considerable and you then may not be able to have two conversations over a single ISDN channel.
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superluditeAuthor Commented:
Is there any online documentation for setting the HO and Branch office through ISDN line ? If I get them. I am a bit confused to configure CM via ISDN ?

Thanks
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superluditeAuthor Commented:
HI grblades,
                      can you provide a simple configuration how to setup Call Manager via ISDN line ?

Thanks
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grbladesCommented:
Sorry I dont have any information and I dont use CM myself.

There wont be any specific configuration for CM with an ISDN. CM configuration will be the standard for remote sites. The data just happens to go over ISDN rather than a fixed line or VPN across the internet.
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superluditeAuthor Commented:
but in our branch site, we only use ISDN (voice and visa terminal), we are not using ISDN data line!
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grbladesCommented:
Then you will need to get a router which has an ISDN interface so it will route traffic from your network and IP phones over the ISDN.
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superluditeAuthor Commented:
Now situation is a bit changed! My boss want that all IP phones should be registered via dsl line, but calls to the outside people and other branch office should be dialed through an ISDN. (Also each branch office should have internal 10 internal 3 digit extensions) ?

-  Is there any method in Call Manager that I can seperate every branch office and define the same internal extensions e.g  Branch A (200,201,202,203...2010), Branch B (200,201,202,...2010) & Branch C (200,201,202...2010) and so on upto 50 branches and same configuration ?

Thanks
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grbladesCommented:
No idea about the CM configuration as I dont use it.

CM uses SCCP which used tcp port 2000 for the control information. You could use policy based routing to route this information over a DSL line and leave the UDP packets (which contain the voice audio) to go over the ISDN. That way registration and call setup will use the DSL but the bandwidth heavy voice will go over the ISDN.
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superluditeAuthor Commented:
Thanks!
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grbladesCommented:
May I ask why you have requested this question be closed?
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