10 - Understanding CUCM Dial Plan Elements and Interactions

Question 1

SRST

Answer 1

Survivable Remote Site Telephony - a feature that allows a branch office router to take over the phone registration and call control for branch IP phones in the event that WAN failure cuts off contact with the central site CUCM cluster

Question 2

CAC

Answer 2

Call Admission Control - refers to one of several techniques for monitoring the total remaining bandwidth available for voice traffic over a WAN link. The purpose of CAC is to prevent the transmission of voice traffic in excess of what the link can support without overflowing the QoS voice priority queue and causing voice packets to be dropped by the router, resulting in very poor quality for all concurrent calls. CAC can be implemented using the CUCM Locations configuration within or between clusters, using RSVP or using Gatekeeper routers

Question 3

AAR

Answer 3

Automated Alternate Routing - an optional configuration that dynamically reroutes calls as PSTN calls when CAC determines there is not enough bandwidth to route the call over the WAN.

Question 4

route pattern

Answer 4

A CUCM configuration that consists of a string of digits and/or wildcards that matches the dialed digits of a phone call and begins the call routing operation. Route patterns are commonly (but not exclusively) used for PSTN dialing

Question 5

route list

Answer 5

linked to a route pattern and lists the top-down preferred order of route groups to use for the call-routing operation; a route list may also perform digit maniputation

Question 6

route group

Answer 6

a collection of devices (gateways and/or trunks) that can physically transmit the call. Route groups are linked to route lists.

Question 7

hunt group

Answer 7

A CME feature; a hunt group allows a call to a specific number to be directed to a defined set of ephone-dns in the desired sequence

Question 8

partition

Answer 8

In CUCM, a partition is a container for dialable entities, including DNs, route patterns, translation patterns, and so on.

Question 9

search space

Answer 9

A Calling Search Space is a top-down ordered list of partitions. A CSS is assigned to the calling device (a phone, DN, gateway and so on). If the target you are trying to dial is in one of the partitions in your current CSS, the call succeeds; if not, it fails

Question 10

CFUR

Answer 10

Destination number to which calls will be forwarded if the phone is unregistered at CUCM. Commonly used in conjunction with SRST to provide call coverage to the DID or attendant number at the branch during a WAN outage