Port Configuration / Roles

Answered Question
Jan 31st, 2007

I'm taking over an existing Install of Unity 4.0(5), CCM 4.1(3). Licenses for 32 ports.

What's interesting about this install is all 32 ports are configured to Answer Calls AND do MWIs, Dialouts, and Traps.

In the other installs I did, I would usually allocate the last 2 or 3 ports just to handle outbounds calls such as MWIs.

Is there a right or wrong way to allocate the ports?

I have this problem too.
0 votes
Correct Answer by mrmccann about 9 years 7 months ago

Couple reason to separate ports out, you're on the right track. And like Rob alluded to these are mostly risks on busy systems:

1) Ports that are enabled for both outdials (MWIs, TRaP, notifications) and answering calls are at risk for collisions between incoming and outgoing calls. We have gone a long way to resolve these collision issues, but it's a tricky timing scenario so can still happen and can result in dropped calls or even locked ports.

2) On busy systems, you might find you need dedicated ports for MWIs/notifications and incoming calls to ensure MWIs are being lit in a timely fashion. For example, if you allow inbound calls on all ports, and all ports are being used by incoming calls at a given time, MWIs will queue up until a port is free. This scenario will also increase the chance of running into a collision, mentioned above.

3) If you do an MWI resynch on a system where all ports are MWI capable, the MWI requests will use up more of the available ports, and you again have increased chance of collisions.

As far as allocation, like Rob refers to, we used to recommend something like 75/25 (answer/outgoing), but removed the recommendation from the docs because it really depends on the usage pattern on the system so we leave it to the admin to decide. For instance, a site with 5000 users that regularly does a system-wide MWI resynch will probably want more than 2-3 ports available for MWIs or else it will take a long time to finish the resynch. A site that uses TRaP or message notifications heavily will also want more than 2-3 ports to make sure outdials always have an available port. Just a couple examples.

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rob.huffman Wed, 01/31/2007 - 13:15

Hi Johnny,

I am not sure about a right or wrong method for allocating ports (especially if the system is not busy) but there are some "best practice' type recommendations. Have a look;

Answer Calls

Check this check box to designate the port for answering calls. These calls can be incoming calls from unidentified callers or from subscribers. As a general guideline, set Answer Calls on approximately 75 percent of the ports.

Message Notification

Check this check box to designate the port for notifying subscribers of messages. Assign Message Notification to the least busy ports, which typically are those with the highest port numbers for the phone system. As a general guideline, set Message Notification, Dialout MWI, and TRAP Connection on approximately 25 percent of the ports.

Dialout MWI

(not used by serial or SMDI integrations)

Check this check box to designate the port for turning MWIs on and off. Assign Dialout MWI to the least busy ports, which typically are those with the highest port numbers for the phone system. As a general guideline, set Message Notification, Dialout MWI, and TRAP Connection on approximately 25 percent of the ports.

From this doc for 4.0.2 but applicable for 4.0.5:

http://www.cisco.com/en/US/products/sw/voicesw/ps2237/products_administration_guide_chapter09186a008014faba.html#36311

Hope this helps!

Rob

johnnylingo Thu, 02/01/2007 - 11:05

Thanks Rob,

Yep, I'm familiar with the roles each port can be configured for, just trying to figure out why you'd want to specifically set some ports for one role.

I'm guessing that if you have ports dedicated for MWIs, that the search process goes faster since they're less likely to try a port being used for an inbound call.

Time to do some digging in the Unity book...

Correct Answer
mrmccann Sat, 02/03/2007 - 00:25

Couple reason to separate ports out, you're on the right track. And like Rob alluded to these are mostly risks on busy systems:

1) Ports that are enabled for both outdials (MWIs, TRaP, notifications) and answering calls are at risk for collisions between incoming and outgoing calls. We have gone a long way to resolve these collision issues, but it's a tricky timing scenario so can still happen and can result in dropped calls or even locked ports.

2) On busy systems, you might find you need dedicated ports for MWIs/notifications and incoming calls to ensure MWIs are being lit in a timely fashion. For example, if you allow inbound calls on all ports, and all ports are being used by incoming calls at a given time, MWIs will queue up until a port is free. This scenario will also increase the chance of running into a collision, mentioned above.

3) If you do an MWI resynch on a system where all ports are MWI capable, the MWI requests will use up more of the available ports, and you again have increased chance of collisions.

As far as allocation, like Rob refers to, we used to recommend something like 75/25 (answer/outgoing), but removed the recommendation from the docs because it really depends on the usage pattern on the system so we leave it to the admin to decide. For instance, a site with 5000 users that regularly does a system-wide MWI resynch will probably want more than 2-3 ports available for MWIs or else it will take a long time to finish the resynch. A site that uses TRaP or message notifications heavily will also want more than 2-3 ports to make sure outdials always have an available port. Just a couple examples.

johnnylingo Sat, 02/03/2007 - 09:45

Just what I was looking for, thanks. That sounds familiar from class, but I didn't see any mention in the "Configuring CallManager and Unity" book.

rob.huffman Sat, 02/03/2007 - 11:58

Hi Michael,

Excellent answer! Your explanation was perfect. 5 points from this end for sure!

Thanks again,

Rob

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