Help Required in Designing IPT Project !!!

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Jun 16th, 2009
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I've got an IPT project of +500 IP Phones with one CCM 6.1 Cluster and two voice gateways,

customer has 1 Head Quarter and 9 Branches ..

i want some clarification for design this project .... i have two options for deploy this project

Option-I) Either i keep cluster (Publisher + Subscriber) at there HQ which is a central location and all branches will connect via WAN.

Option-II) Or i keep Publisher & one Voice Gateway at HQ or Subscriber & other voice gateway at one of Branch.

Customer is forcing me to go for second option, the reason from his point of view is this that what if HQ goes down !!!! if he would have subscriber at other branch so the whole network would have backup !!!!

can any one suggest me which option should i go for ???? or tell me what would be the dependencies or restriction or effects i would have in both of the above options ....

i saw design guides at ... most of the network design in guides has cluster at one location ....

can any one assist me, what should i do & which option should i go for ???


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Overall Rating: 5 (1 ratings)
david-lima Tue, 06/16/2009 - 13:36
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Hi friend, Clustering Over the IP Wan design is useful for customers who require more functionality than the limited feature set offered by SRST, this network design also allows remote offices to support more IP

phones than SRST.

But it has strict design requirements like:

- A 40-ms maximum round-trip delay between any two CUCM servers in the cluster.

- Minimum 1.544 Mb/s for voice and signaling traffic.

If you want the cluster located in your HQ, the branch offices can use the SRST option.

All the best.


Jaime Valencia Tue, 06/16/2009 - 13:52
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Those restrictions for CUCM on delay and BW are incorrect, those are for versions up to 6.0. 6.1 and above restrictions are different. All info is here:

Unified Communications Deployment Models

In short, both options work, and both options are supported as long as you meet network requirements. You would need to check if you can meet the requirements for clustering over the WAN to determine if it's feasible to use it with that customer. If they cannot meet them just show the customer the SRND to explain that it will be unsupported.

If this answers your question please have Anis close the PDI case he opened with the exact same text.

Also, could you care to explain why open a PDI case and also ask at NetPro???



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riazshams Tue, 06/16/2009 - 23:49
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Hi Java,

Anis is my friend he opened the PDI Case first, actually PDI give responce after 24 hours or some time more delay then this .. so thats why i asked the same question on net pro as well coz at net pro i have got quicker responce ....

and thanks for your help about SRND


Jaime Valencia Wed, 06/17/2009 - 06:04
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OK, good to know that. I thought maybe we were doing something wrong =)

That was just due to the working hours we have:

Partner Central

Planning, Design and Implementation Help Desk

When he opened the case the part of the team that covers EMEA was already out of shift so that's why there was some delay.

You gotta keep in mind the working hours to have a right expectation of when to get an answer.



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