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Cisco TelePresence MCU 4200 Series

Using a service prefix to make 100+ registrations with a gatekeeper from the Cisco TelePresence MCU/IP VCR

How do I use a service prefix to make more than 100 registrations with a gatekeeper from the Cisco TelePresence MCU/IP VCR?

The MCU and IP VCR can register up to 100 IDs and/or prefixes with a gatekeeper, provided that the gatekeeper can support that number of registrations. If you require more than this, then you must use a service prefix. Instead of registering every device, conference or recording with the gatekeeper individually, register only a service prefix for the MCU or IP VCR. Then calls starting with the service prefix will be routed to the MCU or IP VCR and the unit will look up the dialed number and act on the associated ID.

Using the IP VCR as an example ..... the IP VCR can have up to 1000 recordings of which 200 can be stored on the internal hard disk. If each recording is assigned a numeric ID and registers with a gatekeeper, then the IP VCR needs to register up to 1000 numeric IDs plus a mandatory H.323 ID. Furthermore, the IP VCR can have up to 50 folders and each folder can have 5 numeric IDs Point to point call incoming prefix, Point to point call outgoing prefix, Recording ID, Recording console ID, and Auto attendant ID). Therefore, in theory, if the IP VCR is fully loaded, then we need to register 1000 + 1 + 250 = 1251 IDs.

Obviously this is not practical and would consume bandwidth. To make it simple and efficient, the IP VCR provides a solution: registering one service prefix. In this case, the Cisco TelePresence IP VCR only registers two entries to the gatekeeper: the service prefix and the H.323 ID. The service prefix tells the gatekeeper that any called number starting with this prefix should be routed to the IP VCR; the gatekeeper does not need to understand the remaining portion of the called number because the IP VCR will interpret it.

Example scenario

Assume that the IP VCR has an H.323 ID of VCR31. It also has two recordings named demo1 and demo2 with numeric IDs 9000101 and 9000102 assigned for them respectively.

In order to allow a user to call in from an endpoint and watch the recordings, we need to register these numeric IDs with a gatekeeper. There are a number of ways in which to do this, described below.

Case 5 is the most efficient if there are many recordings on the IP VCR: the more recordings on the IP VCR, the more bandwidth is saved. By using case 5 the IP VCR can handle hundreds of recordings through a single service prefix.

Case 1: We do not use any type of prefix (i.e. in Settings > Gatekeeper the Prefix for IP VCR registrations is empty and neither Use as prefix for registrations nor Register as a service prefix is selected). However, gatekeeper registration for each recording file is enabled (i.e. in Recordings we have clicked each recording in turn and selected the H.323 gatekeeper check box for Numeric ID registration).

In this case, the IP VCR registers the following 3 entries to the gatekeeper: one as the H.323 ID and two for the recordings:
VCR31
9000101
9000102

A user can dial 9000101 or 9000102 to watch the recordings.

Case 2: We provide a prefix 18 on the IP VCR (i.e. in Settings > Gatekeeper 18 is entered for Prefix for IP VCR registrations and Use as prefix for registrations is selected). Gatekeeper registration for each recording file is enabled as in Case 1. Then the IP VCR registers the following 3 entries (with the added prefix 18 in front of each numeric IDs):
VCR31
189000101
189000102

In this case the user needs to dial 189000101 or 189000102 to watch desired recording.

Case 3: We use the prefix 18 and select Register as a service prefix only deselecting Use as prefix for registrations. Gatekeeper registration for each recording file is enabled as in Case 1. By configuring the IP VCR in this way it registers the following 4 entries:
VCR31
18    *** as a gateway prefix to the gatekeeper ****
9000101
9000102

Now user can call in using either the numeric ID or the "prefix + numeric ID" to play back a recording. For example to play back demo1 he can dial either 9000101 or 189000101.

At the same time, if some recordings are assigned with numeric IDs but not registered to gatekeeper they can be called as well. For example, a third recording demo3 assigned with numeric ID 9000201 but not selected to register to the gatekeeper can be called by dialing 189000201.

Case 4: We select both options Register as a service prefix and Use as prefix for registrations. Gatekeeper registration for each recording file is enabled as in Case 1. Then the IP VCR will register the following 4 entries:
VCR31
18    *** as a gateway prefix to the gatekeeper - as in case 3 ****
189000101
189000102

The user dials “prefix + numeric ID” to play back recordings. For example to play back recording demo1, the user dials 189000101.

As in case 3, the user can dial an unregistered recording by adding the “prefix + numeric ID”  - so long as it has a numeric ID assigned.

Case 5: We select Register as a service prefix only (i.e. Use as prefix for registrations is deselected) but untick registration to gatekeeper on each of the recordings (i.e. in Recordings we have clicked each recording in turn and deselected the H.323 gatekeeper check box in Numeric ID registration).

In this case the IP VCR only registers the following 2 entries to gatekeeper:
VCR31
18    *** this is a gateway prefix to the gatekeeper ***

If the user wishes to watch demo1, he needs to know the numeric ID for that recording (9000101) plus the IP VCR prefix (18) so he can dial 189000101. When the request is received by the gatekeeper it routes the call to the IP VCR because it sees the prefix 18 in the dialed digits. The gatekeeper does not know where 9000101 is but passes it to the IP VCR and lets the IP VCR locate the called party.

Case 6: We use combinations of service prefix and registration for individual recordings: we group recordings by using the service prefix but, at the same time, allow individual recordings to register to gatekeeper. This is a very flexible way to work.

For example, to have 100 recordings called with the same prefix, deselected the H.323 gatekeeper check box in Numeric ID registration for each of these recordings because it is not necessary to register them individually. For some other recordings leave registration enabled. The grouped recordings are called with “prefix + numeric ID” and, for these recordings, calls with “number ID” only will fail because gatekeeper does not know where the call should be routed to. However, the individually registered recordings can be called directly through either “prefix + numeric ID” or “numeric ID” because gatekeeper has knowledge of both the prefix and the registered numeric IDs of those recordings.

This article applies to the following products:

  • Cisco TelePresence IP VCR 2200 / MSE VCR blade
  • Cisco TelePresence MCU 4200 / MSE 8420
  • Cisco TelePresence MCU 4500
  • Cisco TelePresence MSE 8510 blade

April 7th, 2011 TAA_KB_2