Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Community Member

IP Telephony design questions

Hi,

I am planning to deploy 4 small sites (50 to 65 users each) and interconnect them for IP telephony.

What came in my mind was to use ISR routers with CCME software on each site and provide unity for voice mail feature as well, on each site.

The only problem I am having is how all the sites will be able to communicate ? does CCME routers registers between each other and keep a centralized database of all the users of the 4 sites ? That would be great for me as I want a user going from site 1 to site 2 to be able to just connect its laptop and gets its number and environnement like he was at his location (using a softphone installed on his laptop)....

Any hint about this design would be helpful as I am quite new in Cisco IP Telephony.

Can someone suggest another simple way to have a design to solve problem of :

1- mobility of users between sites (they can keep their existing environment)

2- survivability of a site when connection to the other site is lost (users of the same site can call each other)

thanks

13 REPLIES
Cisco Employee

Re: IP Telephony design questions

No, CME are standalone devices and they do not share the configuration with each other.

You can call between each other by configuring the necessary dial peers or using a GK.

If money is not a problem you could use a CUCMBE and use SRST on each site.

This would be a centralized model.

HTH

java

If this helps, please rate

www.cisco.com/go/pdihelpdesk

HTH

java

if this helps, please rate

www.cisco.com/go/pdi
Community Member

Re: IP Telephony design questions

Thanks Java for the guidance.

I've been reading on cisco about the CUCMBE and its seems to be the answer for me. I still have some questions about the desing since I couldn't get everything sorted on my head:

1- The servers are sold with some licensing requirement: I can read licensing term like seat or users but couldn't make any difference. Basically, for the 4 sites (each site is about 60 users), then 200 users for all the customer's users spread accross 4 different locations.Whatdo you think, I can go for this kind of desing for my CUCMBE.

2- Another thing I don't undertsand the fact is the integration of the voice mail features (unity); how will I be able to get that running ? does the server alreay come with integrated voice mails and related features available like auto attendant, call forward, etc ?or do i need to purcahse a separate appliance/equipement for that ?

3- Is it possible in that centralized design to have a unity on each site rather than at the headquarter ? So in an event of a WAN failure each site can have basic functionality to operate internally.

Thanks for your thoughts.

Re: IP Telephony design questions

Before you go jumping on the centralized deployment bandwagon, have you considered the connectivity between this sites?  Do they have point-to-point connections, or pseudo-point-to-point like MPLS?  Or are they using internet-based VPN's?  That's going to be a big design consideration.

Secondly, Unity access in a failover is a little more tricky.  SRST does not support Unity access.  Therefore, if you are using SRST as the redundant solution, local Unity isn't go to do anything for you.  It is possible to configure CME-as-SRST, which does allow Unity access in fallback, but you would lose some flexibility;  From what I understand, CME-as-SRST does not 'auto-discover' phones in fallback as well as SRST.

Community Member

Re: IP Telephony design questions

ccharlebois,

You're correct about the connectivity option. the sites will be in a pseudo mesh topology, so connectivity should not be a problem.

I've found some few answers to some of my questions about the appliance, license and software.

Thanks for your help, guys.

Re: IP Telephony design questions

1- The servers are sold with some licensing requirement: I can read licensing term like seat or users but couldn't make any difference. Basically, for the 4 sites (each site is about 60 users), then 200 users for all the customer's users spread accross 4 different locations.Whatdo you think, I can go for this kind of desing for my CUCMBE.  You do purchase licensing based on the number of users that you need to accomodate.  So, if you have 200 users then you would licensing for 200 users.  It doesn't hurt to accomodate some growth factor in there as well - say 10% or so to be very conservative.  So, for CUCMBE - you buy user licenses but the system cannot support more than 500 users (so that is the max capacity of the system).  For other features like SRST, you purchase that based on the number of users/phones.  Most gateways come with a bundle that provides licensing for a certain number of SRST devices; however, if you need more than that then you just purchase the additional licenses to accomodate the number of users/phones.

2- Another thing I don't undertsand the fact is the integration of the voice mail features (unity); how will I be able to get that running ? does the server alreay come with integrated voice mails and related features available like auto attendant, call forward, etc ?or do i need to purcahse a separate appliance/equipement for that ? CUCMBE is a special co-resident installation of CUCM and Unity Connection.  Both applications reside on a single server and it is a specialized model (MCS 7828).  You cannot cluster the servers so there is no redundancy of software/hardware.  If that server fails, then both CUCM and Unity Connection will go down.  To get to CUCM, you access one set of URLs and to get to Unity Connection you access another.  These 2 applications share the same underlying platform code so thats how this is possible.  Unity Connection will provide the VM features such as Call Handlers (AAs), distribution lists, etc.  CUCM provides the telephony features for phones such as forward, park, hold, resume, etc.  This is a single server, standalone solution.  By nature, if you are homing users from multiple locations to CUCMBE then this is a centralized deployment by default.

3- Is it possible in that centralized design to have a unity on each site rather than at the headquarter ? So in an event of a WAN failure each site can have basic functionality to operate internally. It is possible to have Unity Connection at each site; however, you may find that this is a bit cost-prohibitive if you are looking to have Unity Connection at every site.  For small sites, you could choose to use Cisco Unity Express (CUE) which runs on a module installed in a voice gateway local to each site.  Operationally, this is more of a pain for you because you administer phones centrally but then you have to administer VM individually for every site.  I'm not suggesting that this is a bad idea at all...just giving you some upfront info.  In UC 8.0, there is also a new feature called SRSV which is survivable voicemail.  With this, you would need a Media Gateway (UMG) installed in the gateway at HQ and possibly a UMG at each site (don't recall the details).  Again, this is a module that runs in the gateway.  The UMG works with Unity Connection to sync up data between each other so that in the event of an outage, users at remote sites can still access voicemail via a local CUE module and then when the main Unity Connection system comes back online - the UMG's sync data up so that the loss of voicemail is relatively seemless to an end user.  This requires additional licensing for SRSV, CUE modules, UMG modules and you would need to verify that this feature is available with CUCMBE.  I believe it is because most of the communication is SMTP-based (between UMG and Unity Connection); however, you would need to verify this.  I've not deployed SRSV as I've not experienced a lot of demand for it yet; however, it is a new feature with 8.0 and may be worth looking into. 

In my experience, I think SRST satisfies most needs for failover in your type of setup.  However, it would be up to you to fully flush out your requirements.  In any case, I think you'd benefit from doing homework on the solutions available in general and how they differ from one another.  This will help you to determine what products best fit your requirements.

Hailey

Please rate helpful posts!

Community Member

Re: IP Telephony design questions

Thanks David for your answer.

Is there any way to provide a kind of redundancy to the CUCMBE ? this is the weaknest part of my design....

Cisco Employee

Re: IP Telephony design questions

No, CUCMBE does not provide redundancy itself, this is achieved with SRST.

But if you mean using another CUMCBE and creating a cluster, the answer is no. No clustering for CUCMBE.

HTH

java

If this helps, please rate

www.cisco.com/go/pdihelpdesk

HTH

java

if this helps, please rate

www.cisco.com/go/pdi

Re: IP Telephony design questions

I wouldn't be concerned with seamless redundancy.  Now that the CUCM platform is off of Windows, it is pretty much rock solid.  You need to have some kind of redundancy solution is place, like SRST.  That will provide basic dial-tone services in the case of a server failure, but it will probably only be used in the case of WAN link failure.  WAN link failures are much more common that server hardware failures.  And if they do happen and you have the 24x7x4 SmartNet contract, Cisco will have any replacement parts out to you in 4 hours.

Re: IP Telephony design questions

If you mean something akin to the clustering capabilities of enterprise CUCM, no.  You cannot cluster CUCMBE.  It is a standalone solution / single point of failure.  Your redundancy is provided by SRST.

If you need redundancy, you could go with 2 MCS servers for CUCM.  One would be a Publisher.  One would be a Subscriber.  The placement of the servers for redundancy would depend on network latency, etc.  So you'd have the Subscriber as a primary call agent.  The Publisher as a backup call agent if the Subscriber fails.  Then SRST as a tertiary failover.

For Unity Connection, you can build a cluster; however, you cannot cluster over the WAN in Active-Active standby mode as the B/W and latency requirements prohibit this.  So, options would be a CUC cluster (Pub and Sub) and they could provide active-active redundancy but would be centralized. Again, SRSV is also there as an option depending on your requirements.

Hailey

Please rate helpful posts!

Community Member

Re: IP Telephony design questions

Thanks to all of you guys.

If I decide to go for a distributed model using an ISR CCME on each of the 4 sites, can a user in site1 go to site2 and get his telephony environnement without any configuration on his end equipment ?

Cisco Employee

Re: IP Telephony design questions

If you mean physically move his phone from one site to another then you need to configure the phone on each and every single CME where they can plug it.

If using EM it's the same, you'd need to configure the same EM user on every CME.

CME does not share information or configuration with other CMEs, there is no data replication whatsoever.

HTH

java

If this helps, please rate

www.cisco.com/go/pdihelpdesk

HTH

java

if this helps, please rate

www.cisco.com/go/pdi
Hall of Fame Super Gold

Re: IP Telephony design questions

If you really want to save money, and get the most results with the smaller effort, go for a single ccme system that controls the phones in all sites, an centralize PSTN access with PRI preferably.

Doing this means that either you have wan backup, or you can accept occasional lack of services, because you will be dependant by your mpls or vpn for everything to work.

In any case, do not attempt to do this by yourself, always hire a reputable consultant or certified cisco partner. Otherwise, much troubl and frustration will occur.

Re: IP Telephony design questions

For what you want to do, I would go with CUCM (standard) and Unity Connection.  Based on your numbers, you could go with 7825 servers for the applications which are relatively low cost and then there would be a centralized database for CUCM.  You could also use Extension Mobility to allow users to move around and get their "phone config" at different sites as you're going with centralized design.  For Unity Connection, I'd be willing to talk to you further about how best to do your redundancy model there (if necessary) but I think these solutions with SRST for remote sites is probably the best ticket for what you want to provide.

Hailey

Please rate helpful posts (and you've had a lot of them in this thread)!

859
Views
24
Helpful
13
Replies
CreatePlease to create content