Call Routing

1. Call Routing wyousif@valenciacc.edu

2. Three Responsibilities • The Call Routing Components of Cisco CallManager has three main responsibilities: • To determine which endpoint CallManager should ring based on the digits you dial. • To perform address translation • To support individualized routing wyousif@valenciacc.edu

3. Determining End Points • End points are often other IP phones • Or, numbers controlled by other system. Such as the public switched telephone network, other PBXs. Or other CM clusters • There are cases when the digits you dial do not correspond to a physical device. • Call Park codes • Meet-Me conference code wyousif@valenciacc.edu

4. Performing Address Translation • Address translation allows you to modify the dialed digits and the calling number as the call propagated through the network. • Address Translation is important when a network must pass a call from a private network with its private numbering plan to the PSTN with a standardized numbering plan. • Example: Most PBXs require users to dial an access code to place a call to the PSTN . If CM does not first remove the access code before offering the call to PSTN, the PSTN will reject the call • Address Translation reconciles Private Numbering Plan against PSTN’s numbering plan wyousif@valenciacc.edu

5. Supporting Individualized Routing • The destination you reach when you dial a number might differ completely form the destination your neighbor reaches when your neighbor dials the same number. • This capability is useful to support routing by class of calling user, by organization, or by geographic location. • Example: routing by class of calling user permits you to restrict calls made from lobby phones while allowing your executives full access to international numbers. • Example: routing by organization means that calls from different departments can be routed differently. Also, routing by organization is used to control two different enterprises using one CallManager • Example: Routing by geographic location allows a CM in one location to control phones in two different locations; this ensures that emergency calls from a particular location route to the appropriate emergency response center. wyousif@valenciacc.edu

6. The Seven Fundamentals of Call Routing • Route Patterns • Route Filters • Dialing Transformations • Translation Patterns • Route Lists • Calling Search Spaces • Partitions wyousif@valenciacc.edu

7. Route Patterns and Route Filters • Route patterns and route filters permit CallManger to fulfill its primary responsibility of locating a destination. • Route patterns are the addresses you assign to devices. • Example: Associating the route pattern 8xxx with a gateway means that when you dial a number between 8000 and 8999, your call routes out that gateway. • Route filters are used in conjunction with the special route pattern wildcard @. Route filters restrict the scope of the @ wildcard. wyousif@valenciacc.edu

8. Route Patterns and Route Filters • By including a non-numeric characters called wildcards in a route pattern, you tell CM to ring the associated device for a range of dialed numbers. • Route filters are a special range-refining mechanism. You use route filters with route patterns that contain the special @ wildcard. The @ wildcard allows you to represent the PSTN with a single route pattern. • When you must limit the types of PSTN calls that users can place, route filters limit the scope of the @ wildcard. wyousif@valenciacc.edu

9. Wildcards Route patterns use wildcards, which are digit placeholders that permit you to specify quickly a range of matching digits. • What are the possible matches for the following route patterns: • 1234 • 11X • 12XX • 13[25-8]6 • 13[^3-9]6 • 15!# wyousif@valenciacc.edu

10. Dialing Behavior • In collecting the user’s digits, the call routing component goes through the following steps: • Compare the current sequence of dialed digits against the list of all route patterns and determine which route patterns currently match. This is known as the set of Current Matches. • If current matches is empty, the user’s dialed digit string does not currently correspond with a destination. • If current matches contains one of more member, the call routing component determines the closest match. The closest match s the route pattern in the current matches that matches the fewest number of route patterns. • Example: The dialed digit string 2000 matches both route pattern 2xxx and 20xx. However, there are 1000 different dialed digit strings that match 2xxx, and only 100 dialed digit strings match 20xx: 20xx is therefore the closest match. wyousif@valenciacc.edu

11. Example 1: Dialed Destination =1100 wyousif@valenciacc.edu

12. Example 2: Dialed Destination =1200 wyousif@valenciacc.edu

13. Example 3: Dialed Destination =1300 wyousif@valenciacc.edu

14. Example 3 Continued: Dialed Destination =1300 • The ! wild card at the end of a route pattern means that condition potential matches always holds true. • The system interdigit timeout default to 10 seconds. • When a route pattern ends with a wildcard that matches multiple digits, CM must wait for the system interdigit timeout to expire before it can route the call. • This scenario is needed in non-North American Numbering Plans where many countries have variable-length national dialing plans. wyousif@valenciacc.edu

15. Dialing Behavior Refinements • Urgent Route Patterns: Describes how to interrupt interdigit timing when CM must route a call immediately. • Outside Dial Tone: Describes the logic that determines when CM applies outside dial tone. wyousif@valenciacc.edu

16. Dialing Behavior Refinements • By marking the 9.911 route pattern as urgent, you tell CM to route the call to the emergency center the instant that a user dials 9911 • Outside dial tone is an indication that users expect when CM routes their calls off of the local network wyousif@valenciacc.edu

17. @ Wildcard • @ pattern matches any number that you can dial from your North American home phone • CM interprets @ as a macro expansion. • Four different route patterns in the North American numbering plan: wyousif@valenciacc.edu

18. @ Wildcard Example • When a user dials 555 1212 both route patterns match; however the @ route pattern is more specific and the call will be routed out gateway 1. • To configure a certain route pattern to take precedence over the @ pattern, you have to use route filters (explained soon) wyousif@valenciacc.edu

19. The . wildcard • The . Wildcard does not match digits at all. • The . Wildcard function solely as a delimiter: It divides the dial string into PreDot and PostDot sections • The . Wildcard is used in conjunction with digit discarding instructions. • Example: 9.@ is used to discard the access code section from the dialed string wyousif@valenciacc.edu

20. Building a Route Plan • Building a route plan is a four-step process: • Add Gateway devices • Build route groups from available devices • Build route lists from available route groups • Build a route pattern from available route lists wyousif@valenciacc.edu

21. Next Week Route Filters wyousif@valenciacc.edu