Device Weight: Route Pattern Vs IP Phone

Question

Hi, we are starting the planning for removing two CO class GTD5 switches that route 28,000 DID numbers for the County. The switches are +16 years old and maintenance is expensive. Our Callmanager cluster is designed to replace the existing phone infrastructure (2 CO switches, +60 PBXs, and +20 key systems). Here's a quick overview of our Cluster:
- Publisher only running database services (MCS7845H2)
- Two TFTP servers only running TFTP service and MOH streaming (multicast) (MCS7835H)
- Two subscribers configured as 1-to-1 backup (MCS7845H2)
- CCM version 4.1(3)sr3b
We are planning to add the additional six MCS7845H2 subscribers as we need the capacity.
The first step in our migration is to move all the DID's to new T1/PRI's on a set of six Communication Media Modules (CMM) spread out over four Cat6513 switches.
Essentially our CCM cluster will be acting as a Tandem switch until we get all the trunks moved off the GTD5 CO switches to the CMMs.
Unfornutately all of the 28,000 DIDs are pretty much shot gunned all over the County. So, we will have +20,000 route patterns in the beginning. Over time we will also be converting sites to IP Tel and removing the route patterns as we migrate.
My question: Does a route pattern for one directory number carry the same device weight as an IP phone with the directory number assigned to a line?
We are thinking it does and if it does, then we need to scale up our CCM cluster for 30,000 devices before we start the migration.
Thanks in advance for any advice.
Tom.

Answer 1

Thanks Greg for taking the time to reply. Our cluster design is following the "Cisco Callmanager Best Practices" book. The Publisher and TFTP servers are not running the Callmanager service. This allows 8 subscribers running the Callmanager service in the Cluster.
Our research is trying to understand the cost of a route pattern in terms of the dialing forest and the impact on the subscriber's memory and CPU.
We own two complete prefixes plus another 8,000 DNs from a third prefix. We fortunately do not have an overlapping dialing plan. Each directory number will either be assigned to an IP phone or it will belong to phone on a PBX.
All directory numbers for IP phones belong to the same partition and we also followed the Best Practices book for our dialing plan and use the line/device CSS design.
All +80 remote sites connect back to our GTD5 and the GTD5 routes all the numbers to the remote sites.
We are first migrating all the DID services to our new PRI's handled by the Callmanager cluster. We when start the migration it will be a simple process of a route pattern such as [4-5]XXXX to route the 874-xxxx and 875-xxxx numbers to the GTD5. Then as we disconnect the tie-lines from each remote PBX and re-connect it to the CMM for Callmanager to route, we will need to add all the specific route patterns to route the numbers for the site.
It would be ideal if we did not have to retire the GTD5 switch. We would follow our 5 to 7 year plan to migrate the entire County to IP Tel and leave the GTD5 in place routing the numbers to the remote PBXs. However, we have been directed by management to decommission the GTD5 switch within 12 months.
So we are trying to understand the impact to the subscribers when we begin adding 1,000's of route patterns. We are planning to consolidate as many of the route patterns as possible to reduce the number of route patterns. However, we inherited a design that we refer to as "Number-lose-ability", where individual numbers are routed and not blocks of numbers. Over the years of adds, moves, and changes the numbers have been scattered to all the sites. We have very few sites with consecutive numbers.
Another question that we are trying to answer: what is the cost of a route pattern such as 5555x compared to 10 individual route patterns for the same number range. Again, in terms of memory and CPU on the subscriber doing the digit analysis. We are asking this question because we may have 6 of the 10 numbers going to the same PBX, but the other 4 numbers each going to a different site. To consolidate route patterns we would add the 5555X pattern and the four individual route patterns. What we do not know is how the 5555x is added to the dialing forest. Is it expanded to 10 patterns or just one expression.
Thanks again for any help,