Cisco Unified Communications Manager and Unity Connection: Configuring Class of Service and Call Admission Control

Special Services Configuration

There are certain types of calls that should always be given priority and availability to be dialed from all phones. The first call of this type is 911. When a 911 call is placed, it is important that the call gets through. Not only is it necessary to make the call possible, but you also need to ensure that it goes to the right destination. The following sections discuss some of the issues that can arise with these services.

Special Services Overview

Depending on your local service, various special services might be available. For example, the following is a list of special service numbers that are commonly available in North America. Check with your local phone company to see which of these are valid in your area.

• 311: Nonemergency police services
• 411: Directory assistance
• 511: Travel information
• 611: Phone equipment repair
• 711: Telecommunications Device for the Deaf (TDD) operator
• 911: Emergency

After you determine which services are available, you must configure route patterns that will match these calls. The most important of these calls is 911. Because in an emergency, a person might not think to dial 9 before dialing 911; patterns should be created that enable the call to go out regardless of whether 9 is dialed first. This means that two patterns need to be created, 911 and 9.911. PreDot discard instructions must be applied to the 9.911 pattern so that only 911 is sent out the public switched telephone network (PSTN).

When there are remote locations, things become a little more complicated. Imagine that you have an office in San Jose and a remote office in San Francisco. When callers dial 911 from San Francisco, the call must be routed to the local emergency service, not the service in San Jose. Although this seems obvious, it is sometimes overlooked. To accomplish this, multiple 911 and 9.911 patterns must be created. Partitions and CSS are used to allow phones in each location to match only the pattern that routes the call to the correct location.

For all other special services, the 9.X11 pattern should be sufficient. Once again, be sure to create patterns for each remote location so that the call is routed to the local PSTN.

Another concern when dealing with 911 calls is that some local legislation requires that more detailed location information be sent than just the street address. These laws normally apply to buildings that are over a certain size. Typically the floor and room number are required in addition to the street address. This requirement is referred to as an E911 or enhanced 911. Imagine that someone dialed 911 from a 20-story building and all that was sent was the street address. This would make it difficult to determine which floor, let alone which office, it came from. The solution is to have a database that contains the detailed address information for each phone number in your company. This database is typically maintained by an outside company and is accessible by the emergency service.

Another issue that arises with Communications Manager is that because a phone can be moved so easily, the information in the database can become outdated rather quickly. In addition to this, a feature known as extension mobility makes the Communications Manager system even more nomadic. To deal with these issues, Cisco offers an Emergency Responder product. This product ensures that the correct detailed information is sent when a 911 call is placed. For more details on this product, refer to the "Cisco Emergency Responder Administration Guide" on Cisco.com.

Configuring Special Services Route Patterns

To ensure that special services numbers are accessible, you must create route patterns for them. As mentioned previously, it is recommended that you create at least three patterns for each location. The first two are for 911 services and should be 911 and 9.911. If your location does not use a leading 9 for PSTN access, the first 9 in the 9.911 pattern should be replaced with whatever number is used for PSTN access. The third pattern is 9.X11. This pattern will match all other special services numbers.

The 9.911 and 911 patterns should be marked Urgent Priority so that as soon as the number is dialed, it is sent. If this pattern is not marked Urgent Priority, delays could occur before the call is sent, and this should never happen.

As often happens, one solution creates another problem. I have heard people say that they do not use the 911 pattern because people often dial it by mistake. What happens is that a person dials 9 for an outside line, then presses one to begin a long distance call, and then mistakenly presses one again. This, of course, matches 911 and routes the call to emergency services. It is never recommended that you not include the 911 pattern. Although people misdialing 911 is problematic, it is gravely problematic if 911 cannot be dialed during an emergency. I have heard of many ways people have fixed this problem, but I would not recommend any of them because they all result in either the failure or delay of the call.

An overview of the tasks required to create patterns to allow access to special services numbers follows. Refer to Chapter 4, "Implementing a Route Plan," for detailed steps on how to create route patterns.

• Step 1. Create a 911 route pattern.
• Step 2. Assign a partition to this pattern that all phones in the location can dial. If there are remote locations, a separate pattern must be created and placed in a partition that only phones in that location can reach. This pattern must then point to a route list that will send the call out the local PSTN. Figure 5-16 shows an example of this.
  

  Figure 5-16 Routing 911 Calls for Multiple Locations

  WARNING

  When configuring 911 patterns in environments that include remote locations, it is imperative that you create a route plan that will send the call to the proper 911 operator. For example, if the Communications Manager cluster is in Chicago and a remote location is in San Jose, you must make certain that when a user in San Jose dials 911, the call reaches the San Jose 911 operator, not the Chicago 911 operator. The responsibility to ensure that this works properly is solely upon you. If you are uncertain how to properly implement this, you should seek additional help from an individual with proven experience in this field.

• Step 3. Select a gateway or route list that will send this pattern out the local PSTN gateway.
• Step 4. Select the Urgent Priority and OffNet Pattern (and Outside Dial Tone) check boxes.

  NOTE

  Although it is not necessary to provide an outside dial tone for this pattern, if you do not, the outside dial tone will not be played for any number that begins with 9, until enough digits are dialed so that the number does not match 911. That means, in most cases, when dialing a long-distance number, the outside dial tone is not heard until three digits are dialed. For this reason, it is recommended that you select the OffNet Pattern (and Outside Dial Tone) check box.

• Step 5. Create a 9.911 route pattern. If your location does not use a leading 9 for PSTN access, the first 9 in the 9.911 pattern should be replaced with whatever number is used for PSTN access.
• Step 6. Assign a partition to this pattern that all phones in the location can dial. If there are remote locations, a separate pattern must be created and placed in a partition that only phones in that location can reach. The pattern must then point to a route list that will send the call out the local PSTN. Figure 5-16 shows an example of this.

  WARNING

  When configuring 9.911 patterns in environments that include remote locations, it is imperative that you properly create a route plan that will send the call to the proper 911 operator. For example, if the Communications Manager cluster is in Chicago and a remote location is in San Jose, you must make certain that when a user in San Jose dials 9.911, the call reaches the San Jose 911 operator, not the Chicago 911 operator. The responsibility to ensure that this works properly is solely upon you. If you are uncertain as to how to properly implement this, you should seek additional help from an individual with proven experience in this field.

  WARNING

  Special emergency call routing considerations must be made when deploying device mobility or extension mobility. Since device mobility and extension mobility allow the user to change physical locations you must ensure that the call will be routed based on the physical location of the user. The techniques used to ensure this are beyond the scope of this book. If you are unsure as to how this should be configured you should enlist the assistance of a experienced Cisco voice engineer. The responsibility to ensure all call routing, which includes emergency call routing, works properly is solely upon you.

• Step 7. Select a gateway or route list that will send the pattern out the local PSTN gateway.
• Step 8. Select the Urgent Priority and OffNet Pattern (and Outside Dial Tone) check boxes.
• Step 9. Set the discard digits to PreDot.
• Step 10. Create a 9.X11 route pattern.
• Step 11. Assign a partition to the pattern that all phones in the location can dial. If there are remote locations, a separate pattern must be created and placed in a partition that only phones in that location can reach. The pattern must then point to a route list that can send the call out the local PSTN.
• Step 12. Select a gateway or route list that will send the pattern out the local PSTN gateway.
• Step 13. Set the discard digits to PreDot.
• Step 14. Select the OffNet Pattern (and Outside Dial Tone) check box.

It is essential that after you have created patterns for these services, you make test calls to ensure that the call is routed properly. The steps provided previously are only general practices; additional configuration might be required. There is no guarantee that the previous steps will work in each situation. It is your responsibility to make sure that you test these services thoroughly before the system goes live.