Question to Gurus

[Trojanhose]

I have the following setup:

HQ: 1pub/1sub   400 phones / own Gateway

BR1: 1pub/1sub  30phones   / own Gateway

BR2: 1pub/1sub  30phones   / own Gateway

BR3: 1pub/1sub  30phones   / own Gateway

Each site has it's own dial plan. All CUCMs are trunked for internal calls between sites.

I was now asked to redesign this as 2 CUCM for 30 phones seems to be too much.

I was thinking of getting rid of all CUCMs in the branches and replacing them with SRST.

Here are my questions:

1) Is my design plan (SRST) good? do you have any Idea of other possible designs?

2) What is the WAN requirement for this setup? the minimum  bandwith between sites? assuming all phones in  branches will now be regstering to the CUCM in HQ

3) What is the benefit of getting rid of all the server at branches? I mean beside having 6 CUCM server at hands to use for other stuff.what do I gain from using only 2 CUCM for everything.

Regards.

[Sebastiandm_2]

Trojan,

What version of CUCM are you using ? There are many different factors to take into account when choosing the best design for your network, the following link will provide you with information on Cisco`s design recommendations and you can use this info to apply to your network.

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_implementation_design_guides_list.html

[Trojanhose]

CUCM 7.x

I already went through the SRND.I already provided all the details needed. Thanks.

[Trojanhose]

Anyone can help here?

[greg.schrage]

What model of GW do you have at each site?  SRST numbers are limited by router model.

Whats the Wan connection for each site?  MPLS?  QOS?

How many of the 30 will need to be on calls at the same time?

[Trojanhose]

What model of GW do you have at each site?

2821

Whats the Wan connection for each site?  MPLS?  QOS?

It's a 2mb normal WAN connection to all other sites. No QOS what so ever.

How many of the 30 will need to be on calls at the same time?

I would say around 10 to 15 concurrent calls.

[Senthil Kumar Sankar]

Hi

1) Is my design plan (SRST) good? do you have any Idea of other possible designs?

   You are trying to implement, Multisite with Centralized Call Processing (i.e, 1 cluster)
   A CUCM cluster can have maximum of 2000 remote sites within a cluster, so you can go ahead

2) What is the WAN requirement for this setup? the minimum  bandwith between sites? assuming all phones in  branches will now be regstering to the CUCM in HQ
  
   Minimum of 786kbps or greater WAN link speeds,Video is not recommended on WAN connections that    operate at speeds lower than 768 kbps.

3) What is the benefit of getting rid of all the server at branches? I mean beside having 6 CUCM server at hands to use for other stuff.what do I gain from using only 2 CUCM for everything.

   You will have Single point of administration for users for all remote sites

In addition to that, you can have locations feature and RSVP for CAC(Call Admission Control)

I would suggest you to have a look at the section Best Practices for the Centralized Call Processing Model in the below link

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/models.html#wp1043616

Regards

Senthil

[a.iliev]

Hi Mate,

Here is a practical answer for you

1. SRST is the standard way of dealing with branches of this size. Depending onhow your network  is structured ( i.e. if one of the branches also have connections to the other branches serving as a sort of BCP site and the BW between this ssite and the HQ) you can have a split cluster working  over the WAN.  Most of the times though you'll just have the HQ housing the pub abd sub and all other small sites running SRST in case they loose connectivity to the HQ.

2. As specified you have a design uses several clusters, so I assume you have done your BW calculations for the current design. The delta is centralised signalling taking between 1 and 3 K excl overheads per call. BW is dependent on the number of concurent calls traversing the WAN ( not the number of calls per site as local site calls and call to customers will only send signalling over the WAN, RTP will be contained within the LAN. On Serial links using G.729 each call takes up about 25Kbps not using cRTP, on Ethernet about 50.  In any case the exact BW will depend on your particular setup - L2 protocol type, codec used, encryption, etc.

3. Mostly cost savings related to ongion server management, Smartnet, UCSS, etc, as well as simplified administration - equal to lower resource requirements.

Cheers

Andrey