Planning for Cisco Emergency Responder 2.0

Cisco Emergency Responder Administration Guide 2.0 (Cisco ER) helps you manage emergency calls in your telephony network so that you can respond to these calls effectively and so that you can comply with local ordinances concerning the handling of emergency calls. In North America, these local ordinances are called "enhanced 911," or E911. Other countries and locales might have similar ordinances.

Because emergency call ordinances can differ from location to location within a country, region, state, or even metropolitan area, Cisco ER includes the flexibility you need to fit your emergency call configuration to specific local requirements. However, because ordinances do differ from location to location, and because security requirements differ from company to company, you need to do extensive planning and research before you can deploy Cisco ER in a manner that fits your legal and security needs.

These topics help you understand emergency call ordinances, how Cisco ER helps you meet the ordinances, and what you need to do to deploy Cisco ER successfully:

Understanding Enhanced 911 (E911)

Enhanced 911, or E911, is an extension of the basic 911 emergency call standard in North America. These topics describe E911 requirements and terminology.

Overview of Enhanced 911 Requirements

Enhanced 911 (E911) extends the basic 911 emergency call standard to make it more reliable.

When using basic 911 in North America, if a caller dials 911, the call is routed to a Public Safety Answering Point (PSAP), also called the 911 operator. The PSAP is responsible for talking to the caller and arranging the appropriate emergency response, such as sending police, fire, or ambulance teams.

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The emergency call must be routed to the local PSAP based on the location of the caller. (In basic 911, the call simply needs to be routed to some PSAP, not necessarily the local one.)

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The caller's location information must be displayed at the emergency operator's terminal. This information is obtained by querying an automatic location information (ALI) database.

In E911, the location of the caller is determined by the Emergency Location Identification Number (ELIN), which is a phone number the PSAP can dial to reconnect to the emergency caller if the emergency call is cut off for any reason, or if the PSAP simply needs to talk to the caller again. The emergency call is routed to the PSAP based on the location information associated with this number. For multi-line phone systems, such as an office system, the ELIN can be associated with more than one telephone by grouping the phones in an Emergency Response Location (ERL). In this case, the location the PSAP receives would be the address of an office building. For large buildings, the location would include additional information such as floor or region on a floor. Each ERL requires a unique ELIN.

In addition to these general E911 requirements, each locality can further extend or limit these requirements. For example, a city ordinance might include specific limitations on the size of an ERL (such as, no larger than 7,000 square feet), or on the number of phones that can be included in an ERL (such as, no more than 48 phones). You must work with your service provider and local government to determine the exact E911 requirements in your area.

Understanding E911 and Cisco Emergency Responder Terminology

Table 1-1 E911 and Cisco Emergency Responder Terminology
Term	Definition
ALI	Automatic location information. Information that ties an ELIN to a location, is used to route emergency calls from that ELIN to the correct local PSAP, and is presented to the PSAP to help the PSAP locate the emergency caller. In Cisco ER, you fill in ALI data for each ERL and submit the ALI data to your service provider for inclusion in the ALI database.
ANI	Automatic number identification. ANI is another name for ELIN. This document uses ELIN instead of ANI.
CAMA	Centralized automated message accounting. An analog phone trunk that connects directly to an E911 selective router, bypassing the Public Switched Telephone Network (PSTN).
DID	Direct inward dial. A telephone number obtained from your service provider that can be used to dial into your telephone network. DID numbers are used for ELIN.
ELIN	Emergency location identification number. A phone number that routes the emergency call to the local PSAP, and which the PSAP can use to call back the emergency caller. The PSAP might need to call the number if the emergency call is cut off, or if the PSAP needs additional information after normally ending the emergency call. See ALI.
emergency call	A call made to the local emergency number, such as 911. Cisco ER routes the call to the service provider's network, where the call is routed to the local PSAP.
emergency caller	The person who places the emergency call. The caller might require help for a personal emergency, or might be reporting a more general emergency (fire, theft, accident, and so forth).
ERL	Emergency response location. The area from which an emergency call is placed. The ERL is not necessarily the location of the emergency. If an emergency caller is reporting a general emergency, the actual emergency might be in a different area. In Cisco ER, you assign switch ports and phones to ERLs, and ERL definitions include ALI data.
ESN	Emergency service number.
ESZ	Emergency service zone. The area covered by a given PSAP. This area usually includes several police and fire departments. For example, a city and its suburbs might be serviced by one PSAP. Each ESZ is assigned a unique ESN to identify it.
MSAG	Master street address guide. A database of ALIs that enables proper routing of emergency calls to the correct PSAP. In Cisco ER, you export your ALI definitions and transmit them to your service provider, who ensures the MSAG is updated. You must negotiate this service with your service provider—it is not a service provided directly through Cisco ER.
NENA	National Emergency Number Association. The organization that recommends data and file formats for ALI definitions and other emergency call requirements in the United States. Cisco ER uses the NENA formats for ALI data export files. Your service provider might have additional restrictions on data format, so ensure that your ALI entries abide by your service provider's rules.
PSAP	Public safety answering point. The PSAP is the organization that receives emergency calls (for example, the 911 operator) and is staffed by people trained in handling emergency calls. The PSAP talks to the emergency caller and notifies the appropriate public service organizations (such as police, fire, or ambulance) of the emergency and its location.

Understanding Cisco Emergency Responder

These topics provide an overview of Cisco Emergency Responder and how you can use it in your network.

Cisco Emergency Responder 2.0 Features

These are the major new and enhanced features of Cisco Emergency Responder (Cisco ER) 2.0:

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Cisco ER 2.0 clusters can include both Cisco ER 2.0 and Cisco ER 1.3 server groups

See the Release Notes for Cisco Emergency Responder 2.0 for a list of hardware and software supported in Cisco ER 2.0.

Network Hardware and Software Requirements

Cisco ER 2.0 supports a variety of hardware and software components. For the complete list of supported hardware and software, see the Release Notes for Cisco Emergency Responder 2.0.

Licenses for Cisco Emergency Responder 2.0

Cisco ER 2.0 uses a web-based system for requesting, creating, and delivering product licenses. Once you register your Cisco ER product through the Cisco.com website, a file containing the server license will be sent to you as a text-file email attachment.

Licenses for Initial Installation

Cisco ER 2.0 does not require a license key for initial installation. Unlicensed Cisco ER 2.0 software will operate normally for 60 days after it is installed, with a capacity of 100 phones. Additional user licenses are not effective until a server license is installed. If you do not install a server license within 60 days, the Cisco ER 2.0 system shuts down.

Migrating Licenses

When migrating from Cisco ER 1.3 to Cisco ER 2.0, you will need to order upgraded licenses using the procedures given later in this section. Existing Cisco ER 1.3 licenses cannot be converted to Cisco ER 2.0 licenses.

Uploading License Files

You can upload license files to the Cisco ER servers using the Cisco ER Administration web interface. To do so, follow these steps:

Step 2

Select System > License Manager. The License Manager page appears.

Step 3

In the Details of Cisco ER Licenses section, select the server to which you will upload the license file from the pulldown menu.

Step 5

Use the Browse... button to select the license file to upload from your local system.

Step 6

Click Upload. The selected license file is uploaded to the Cisco ER server.

Server Licenses

You must purchase a server license for each Cisco ER server in a server group. Each server license includes an implicit user license for 100 users.

Step 1

Order Cisco ER 2.0 using your preferred ordering method. You will receive a Product Authorization Key (PAK) along with Cisco ER 2.0.

After processing, you will receive the server license file as a text-file email attachment.

Step 3

Save the server license file to a local server so that it can be uploaded to the Cisco ER server.

User Licenses

Each Cisco ER server license includes 100 user licenses. User licenses are shared by both primary and secondary Cisco ER servers irrespective of where they are installed.

The total number of user licenses available in a server group at any given time is the sum of the user licenses available on both servers in the server group.

Step 1

Order additional or upgraded user licenses. You will receive a Product Authorization Key (PAK) for each additional user license.

Step 2

Go to Cisco.com and register your Cisco ER by supplying the PAK and the Media Access Control (MAC) address of your Cisco ER server. User licenses are usually installed on the primary Cisco ER server.

After processing, you will receive the user license as a text-file email attachment.

Step 3

Save the user license file to a local server so that it can be uploaded to the Cisco ER server.

Determining Your License Requirements

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Order two server licenses for each Cisco ER group: one server license for the primary (Publisher) server and a separate server license for the secondary (Subscriber) server.

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You cannot share a server license between the Publisher server and the Subscriber server.

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User licenses can be shared between Publisher and Subscriber servers within each Cisco ER group. This includes both implicit 100-user licenses provided by the primary and secondary server license.

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One service license for your Cisco ER Publisher server; this license also provides for 100 users

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One service license for your Cisco ER Subscriber server; this license provides for another 100 users.

How Cisco Emergency Responder Fits Into Your Network

Figure 1-1 shows how Cisco Emergency Responder (Cisco ER) fits into your network.

To track phones, Cisco ER queries Cisco Unified Communications Manager for a list of phones registered with the cluster. Then, Cisco ER queries the switches on the network (the ones you have identified to Cisco ER) to determine the port to which the phones are connected. Cisco ER does this tracking at regular intervals during the day so that it can identify when a phone moves. See the "Configuring Switches for Cisco Emergency Responder" section on page 5-39 for more information about setting up switches for Cisco ER. See the "Managing Phones" section on page 5-47 for information on how to configure switch ports so that Cisco ER can send emergency calls to the correct PSAP based on port and phone location.

Optionally, you can have an SMTP email server in your network or with a service provider. You can configure Cisco ER to send email to your onsite alert (security) personnel to notify them of emergency calls. If the server is set up as an email-based paging service, the personnel are paged.

Finally, you need a gateway with a PRI or CAMA link to the service provider's network so that Cisco ER can route emergency calls to the local public safety answering point (PSAP).

Figure 1-1 shows one Cisco ER group supporting a single Cisco Unified Communications Manager cluster. You can support more than one Cisco Unified Communications Manager cluster with a single Cisco ER group, as long as the Cisco Unified Communications Managers are running the same software version. If you have a larger network, you can install multiple Cisco ER groups and create a Cisco ER cluster. See the "Understanding Cisco Emergency Responder Clusters and Groups" section for a discussion of this more complex installation.

What Happens When an Emergency Call Is Made

This topic describes the process Cisco Emergency Responder (Cisco ER) uses to handle emergency calls. Understanding this process can help you set up Cisco ER correctly and troubleshoot problems you might encounter.

Cisco ER converts the calling party's number to the route pattern configured for the caller's ERL. This route pattern is configured to pass the appropriate emergency location identification number (ELIN) to the public safety answering point (PSAP). The ELIN is a telephone number the PSAP can use to call back the emergency caller.

Cisco ER saves a mapping between the caller's extension and the ELIN, by default, for up to three hours. The mapping might be overwritten by subsequent calls before the entry times-out. You can also configure the time-out to be longer or shorter than three hours (see the "Cisco ER Group Settings" section on page A-3).

Cisco ER routes the call using the route pattern configured for the caller's ERL. This route pattern in turn uses the configured route list to send the emergency call to the appropriate service provider's network. The service provider looks up the ELIN in the automatic location information (ALI) database, and routes the call to the appropriate local PSAP. The PSAP receives the phone call and looks up the ALI in the ALI database.

Concurrently, Cisco ER sends web alerts to the Cisco ER user. In addition, Cisco ER calls the onsite alert (security) personnel assigned to the ERL. If you configure an email address for the personnel, Cisco ER also sends an email. If the address is for an email-based paging service, the personnel get pages instead of emails.

If an emergency call is cut off unexpectedly, the PSAP can call back the emergency caller using the ELIN. The call to the ELIN is routed to Cisco ER, and Cisco ER converts the ELIN to the last cached extension associated with the ELIN. The call is then routed to the extension.

To ensure proper performance and eliminate major points of failure, verify the following:

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For the emergency call to be routed correctly, the caller's phone must be assigned to the correct ERL. To check the correctness of the ERL associated with the phones, use the ERL debug tool.

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Another potential problem in routing the call correctly lies with the ELIN definition. If you assign the ELINs route pattern to the wrong gateway, the emergency call can be routed to the wrong network. This can send the emergency call to the wrong PSAP.

Work with your service provider to determine how many gateways you need and where to connect them. These requirements are based on the service provider's network topology more than on your network's topology. In the United States, the emergency call network is tandem to the PSTN, so simply connecting to the PSTN does not ensure the correct routing of emergency calls.

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The call might be routed incorrectly in the service provider's network if the information in the ALI database is incorrect. Ensure that you export your ALI data and submit it to the service provider, and resubmit it whenever you change ELIN or location information.

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The PSAP might not be able to successfully call back an emergency caller if a lot of emergency calls are made from an ERL. Cisco ER caches the ELIN-to-extension mapping for up to three hours. If you have two ELINs defined for an ERL, and three emergency calls are made in a three-hour window, the first ELIN is used twice: once for the first caller, then reused for the third caller. If the PSAP calls the first ELIN, the PSAP will reach the third caller, not the first caller. The likelihood of this problem arising depends on how many ELINs you define for an ERL and the typical rate of emergency calls in the ERL.

Cisco Emergency Responder's Call Routing Order

Cisco ER directs emergency calls based on the location of the phone from which the call is placed. The location of the phone is determined by the following methods, in order of precedence:

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IP Phones tracked by another (remote) Cisco ER server group in the same Cisco ER cluster—The remote server group tracks an IP phone behind a switch port or by IP subnet. When an emergency call is received, it is forwarded to the Cisco Unified Communications Manager cluster served by the remote Cisco ER server group. See the "Phones Moving Between Clusters" section.

Note MAC and/or IP address tracking is recommended for Cisco Unified IP Phones. IP phones which are not tracked by MAC or IP address will appear as unlocated phones, even if they are assigned a location by manual line number configuration.

Customers should resolve problems that prevent IP phones from being tracked by MAC or IP address (see the "Too Many Unlocated Phones" section) so that IP phones will be not removed from the Unlocated Phones page. An ERL may be assigned directly to an IP phone on the Unlocated Phones page, but this assignment will not take effect if the phone is assigned a location by manual line number configuration. Use the ERL Debug Tool to determine the ERL assignment in effect for an IP phone that appears on the Unlocated Phones page.

Cisco ER defines unlocated phones as those Cisco Unified IP Phones which meet all of the criteria below:

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The IP phone is registered to a Cisco Unified Communications Manager known to the Cisco ER group.

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The MAC address of the IP phone is not defined as a synthetic phone in Cisco ER.

Note Cisco Unified IP Phones tracked by a remote Cisco ER server group and IP phones having line numbers manually assigned to an ERL will also appear in the Unlocated Phones screen.

Cisco ER provides a procedure to assign an ERL to IP phones that are displayed on the Unlocated Phones screen. This assignment associates the MAC address of the unlocated phone with an ERL that is selected by the administrator. These rules apply to this association:

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The association of an ERL with an IP phone on the Unlocated Phones page does not change the status of the IP phone; it remains on the Unlocated Phones page due to the fact that the IP phone will continue to match the criteria for unlocated phones described above.

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The ERL association is used only when the IP phone is unlocated, as determined by Cisco ER, using the above rule.

For example, Phone A is currently unlocated and appears on the Unlocated Phones page. Using the ERL assignment feature for unlocated phones, Location A is assigned as the ERL for this phone. A subsequent phone tracking cycle finds Phone A behind a switch port and it no longer appears in the Unlocated Phones page. The Phone A-to-Location-A assignment is no longer valid. Because the association is persistent, if the IP phone is unlocated at any future time, the assignment will be valid.

Location Information for Calls Forwarded by CTI Applications

If emergency calls are forwarded to 911 by computer telephony integration (CTI) applications, such as Cisco Unity, then the location used for call routing and PSAP reporting will be the location of the application server, not the location of the original caller. This remains true even if the application retains the original calling line number, as is made possible in Cisco Unified CallManager 4.2(3) and 4.3, and in Cisco Unified Communications Manager 5.1 and 6.0. For this reason, you should dial 911 directly.

Understanding Cisco Emergency Responder Clusters and Groups

Deploy Cisco Emergency Responder (Cisco ER) in your network as a pair of redundant servers. One server is designated as the Publisher server and the other as the Subscriber server. Each Cisco ER Publisher server and Subscriber server make up a Cisco ER Server Group. Configuration data for the server groups is stored in a database on the Publisher. This data is replicated to the Subscriber.

A Cisco ER cluster is a set of Cisco ER server groups that share data to provide correct emergency call handling capabilities. Cisco ER cluster information is stored in a central location in the cluster called the cluster database. A Cisco ER server group is considered part of a cluster when the group points to the same cluster database as the other server groups in that cluster.

During installation, both databases are created on each Cisco ER server. However, only one Cisco ER server contains cluster data.

Note You cannot deploy different versions of Cisco ER in the same Cisco ER group. If you are upgrading to Cisco ER 2.0, make sure to upgrade both Cisco ER servers to version 2.0.

Figure 1-3 shows how Cisco Emergency Responder (Cisco ER) groups can be joined in a single Cisco ER cluster.

Figure 1-3 Understanding the Relationship between Cisco ER Groups and Cisco ER Clusters

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There are two Cisco Unified Communications Manager clusters, CUCM cluster A and CUCM cluster B.

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Cisco ER Server Group 1 and Cisco ER Server Group 2 form a single Cisco ER cluster.

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Cisco ER Server Group 1 supports CUCM cluster A and Cisco ER Server Group 2 supports CUCM cluster B.

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Cisco ER1 Publisher's cluster database stores the Cisco ER cluster information for both Cisco ER server groups. Dotted lines show the Cisco ER servers communications with the cluster database host.

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Each Cisco ER server has a database containing the Cisco ER configuration information.

Note For Cisco ER intra-cluster phone tracking to work accurately, a Cisco ER server in the cluster must be able to be found by its hostname and must be able to be reached on the network from all other Cisco ER servers.

Note If you enter the system administrator's e-mail account in the System Administrator Mail ID field when you configure the Cisco ER Server Group Settings, the system administrator receives an e-mail notification when the standby server handles a call or when the standby server takes over for the primary server. (See the "Configuring a Cisco Emergency Responder Server Group" section on page 5-16.)

Moving Phone Between Clusters

The following scenario illustrates how Cisco ER treats phones moving between clusters:

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If both the Cisco ER servers (Publisher and Subscriber) in SGB go down, SGA will still display Phone_1 in SGB.

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Calls made from Phone_1 during this time will be redirected to SGB and Cisco ER will take the same steps to route this emergency call when Cisco ER servers are not there in SGB.

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Phone_1 will also be treated like any other phone in SGB when both the SGB Cisco ER servers are down.

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It will be discovered after the next incremental phone tracking on SGA and then in SGC.

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If Phone_1 moves back to SGA, it will be discovered in the next incremental phone tracking and displayed under the corresponding switch port.

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A single Cisco ER group cannot support clusters with a mix of Cisco Unified Communications Manager versions. For example, Cisco ER can support all Cisco Unified CallManager 4.2 clusters or all Cisco Unified CallManager 5.1 clusters.

However, a Cisco ER cluster can contain Cisco ER groups that support different versions of Cisco Unified Communications Manager. In this way, Cisco ER can support a mix of Cisco Unified Communications Manager versions in your telephony network.

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A Cisco ER 2.0 server group can operate with other Cisco ER 2.0 server groups or with Cisco ER 1.3 server groups.

Determining the Required Number of Cisco Emergency Responder Groups

To ensure efficient Cisco Emergency Responder (Cisco ER) performance, you should take the limits each Cisco ER group can support into account when planning your Cisco ER deployment. Keep in mind that a single Cisco Unified Communications Manager cluster can only be supported by one Cisco ER group, although a single Cisco ER group can support more than one Cisco Unified Communications Manager cluster.

Refer to the Release Notes for Cisco Emergency Responder 2.0 for the capacities of a single Cisco ER group with your configuration. Be aware that you might meet the maximum figures for one limitation without reaching the figures for another. For example, you might define 1,000 switches, but have fewer than 30,000 switch ports.

You can install additional groups to manage larger networks. Each Cisco ER group can work with one or more Cisco Unified Communications Manager clusters.

In addition to these per group limits, you must also consider the territories covered by the service provider's ALI database providers. If your network extends into more than one ALI database provider's territory, you should use the ALI Formatting Tool (AFT) to export ALI records in multiple ALI database formats.

Step 1

Obtain an ALI record file output from Cisco ER in standard NENA format. This file contains the records destined for multiple LECs.

Step 2

Make a copy of the original file for each required ALI format (one copy per LEC).

Step 3

Using the AFT of the first LEC (for example, LEC-A), load a copy of the NENA-formatted file and delete the records of all the ELINs associated with the other LECs. (For information on using the AFT, see "Using the ALI Formatting Tool.") The information to delete can usually be identified by NPA (or area code).

Step 4

Save the resulting file in the required ALI format for LEC-A, and name the file accordingly.

If AFTs are not available for each LEC, you can achieve a similar result by editing the NENA-formatted files with a text editor.

Data Integrity and Reliability Considerations

The correct routing of emergency calls to the local PSAP is based on your ERL configuration. Inside your network, correct identification of the ERL for a phone determines which gateway is used to connect to the service provider's network. In the service provider's network, the routing is based on the ELIN, which is also used to look up the ALI for the caller. Thus, your ERL configuration must be reliable so that the correct ELIN is assigned to the emergency call.

These are the things to consider to maintain the reliability of your ERL configuration:

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ERLs are assigned to switch ports based on the location of the device attached to the port, not the location of the port itself. Thus, if you change the wire plugged into a port (for example, by switching wires between two or more ports), there is the potential that the device now plugged into the port is actually in a different ERL. If you do not change the ERL assigned to the port, the incorrect ELIN will be used for the port, and the wrong ALI sent to the PSAP.

This type of change will not normally result in an incorrectly routed call, because it is unlikely that a single LAN switch will connect to ERLs serviced by separate PSAPs. However, the ALI sent will be incorrect, with the possibility that your security staff will search the third floor for an emergency when the caller is actually on the fourth floor.

To prevent this problem, ensure that your wiring closets are secure, and train your networking staff to avoid swapping wires between switch ports.

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If you have phones that Cisco ER cannot automatically track, ensure that any moves, adds, or changes to these phones also result in an update to the Cisco ER configuration. See the "Manually Defining a Phone" section on page 5-53 for information on defining these types of phones.

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Prior to Cisco ER 1.2, if registered phones were not found behind a switch port, Cisco ER would list the phone in the Unlocated Phones page.

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If a registered phone is not found behind a switch port, it may be found in one of the configured IP subnets.

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If a registered phone is not behind a switch port, or the IP Subnet of the phone is not configured, or the phone is not configured as a synthetic phone, Cisco ER lists the phone in the Unlocated Phones page.

To determine the ERL that Cisco ER will use for call routing, use the ERL Debug Tool to search for the phone. The search yields the current ERL that will be used in routing the emergency call from this phone and also why Cisco ER chose that ERL. For more information, see the "Using the Cisco Emergency Responder Admin Utility" section.

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When you install Cisco ER 2.0, you install a Publisher server (primary) and a Subscriber server (backup) that points to the Publisher. The Publisher server and the Subscriber server make up a Cisco ER Server Group. This redundancy helps to ensure that the failure of one server does not affect the ability to make emergency calls. Consider installing the standby server in a physically separate location from the primary server, and on a separate subnet not separated by a WAN link. This separation can protect against some types of disruption, for example, a fire in the building housing the primary server, or the loss of connectivity to the subnet hosting the primary server.

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Ensure that the Cisco ER configuration is regularly updated as switches are added, removed, or upgraded (for example, by adding or changing modules). When you change a switch, run the switch-port and phone update process on the switch by viewing the switch in Cisco ER and clicking Locate Switch Ports. See the "Identifying the LAN Switches" section on page 5-42 for more information.

Any phones connected to undefined switches are listed as unlocated phones in Cisco ER. If you changed a defined switch, new or changed ports become ports without any ERL association. You should assign ERLs for the new or changed switch ports. See the "Understanding the Network Administrator's Role" section and the "Understanding the ERL Administrator's Role" section for information on the recurring tasks involved in network changes.

Preparing Your Network For Cisco Emergency Responder

These topics describe the steps you should take to prepare your network before deploying Cisco Emergency Responder.

Obtain CAMA or PRI Trunks to the PSTN

To handle emergency calls, you must obtain PRI or CAMA trunks to connect to your service provider. Your service provider might support only one type of trunk. If you have an option, work with your service provider to decide on the type of connection that works best for you.

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PRI—If you use a PRI connection for emergency calls, you can share the connection with regular telephone traffic. If you use the trunk for regular traffic, monitor trunk usage to ensure there is sufficient available bandwidth to handle emergency calls. If your capacity is inadequate, an emergency caller might get a busy signal when trying to make the call. Ensure you do capacity planning based on emergency call requirements.

When you configure the PRI trunk, you must configure it so that it sends the actual calling party's number rather than a generic number (such as the main number of the site). Otherwise, the PSAP will not receive the expected ELIN, and the emergency call might not be routed to the right PSAP.

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CAMA—CAMA trunks are dedicated to emergency calls, and are available in most areas. You do not need to do any capacity planning for CAMA trunks, because they are never used by regular voice traffic.

Work with your service provider to determine how many trunks are required for your network. For example, some service providers use a guideline of two CAMA trunks for 10,000 phones.

Also, the number of trunks can differ depending on the distribution of your offices with respect to the local PSAPs. For example, if you have offices in New York and Chicago, you would need trunks in both cities, even if your total number of telephones would require fewer trunks if your office was only in New York. Your service provider, who knows the layout of the emergency call network, can direct you on trunk requirements that are based on PSAP accessibility.

Obtain DID Numbers from Your Service Provider

You must obtain direct inward dial (DID) numbers from your service provider for use as emergency location identification numbers (ELIN) for your emergency response locations (ERL).

In general, you must have at least one unique number per ERL. Emergency calls are routed to the local PSAP based on the ELIN of the ERL, so if you do not have unique ELINs, the call cannot be routed properly. The ALI database provider also might not accept ALIs that include duplicate ELINs.

You might want to have more than one ELIN per ERL. If your ERLs include more than one phone, you might have more than one emergency call made from an ERL in a short time (less than three hours). If you assign only one ELIN to the ERL, that ELIN is reused for each emergency call. Thus, if four people make emergency calls in the space of an hour, if the PSAP calls the ELIN, the PSAP will connect to the last caller. This might be a problem if the PSAP was trying to contact one of the earlier callers.

If you define more than one ELIN per ERL, Cisco Emergency Responder (Cisco ER) uses those ELINs in sequence until all are used, then reuses the ELINs in order. Cisco ER maintains the link between the ELIN and the extension of the actual emergency caller for up to three hours.

Because you need to purchase these DIDs from your service provider, you must balance the needs of your budget with the needs of maintaining the capability of the PSAP to reach the correct caller.

Note The number of DIDs you obtain is not related to the number of emergency calls Cisco ER can handle. Because Cisco ER reuses the ELINs you define, every emergency call gets handled and routed to the correct PSAP. The number of ELINs only influences the success rate of the PSAP calling back the desired emergency caller.

Negotiate ALI Submission Requirements With Your Service Provider

Emergency calls are routed to the appropriate PSAP based on the emergency location identification number (ELIN) of the emergency caller. To route the call, the telephony network must have your automatic location information (ALI) that maps these ELINs to a location. Besides routing the call appropriately, the ALI database also supplies the location information that appears on the PSAPs screens to help them locate the caller.

Cisco ER includes features to create ALIs and to export them in a variety of formats that should be acceptable to your service provider. After you create your ERL/ALI configuration, you must export the ALI data and send it to the ALI database provider.

How you send the data can vary from location to location or service provider to service provider. You must work with your service provider to determine the services you can select for submitting ALI data. At a minimum, you must know the data format they expect, and the transmission method they require.

Tip

Before deploying Cisco ER throughout your network, test the ALI submission process with your service provider. With your service provider's help, test that the PSAP can successfully call back into your network using the ALI data. Each service provider and ALI database provider can have slightly different rules concerning ALI information. Cisco ER allows you to create ALI data according to the general NENA standards, but your service provider or database provider might have stricter rules.

Upgrade Switches and Phones

The most powerful capability of Cisco Emergency Responder (Cisco ER) is the ability to automatically track the addition or movement of telephones in your network. This dynamic capability helps ensure that emergency calls are routed to the local PSAP, even if a user moves a phone between cities. This can reduce the cost of maintaining your telephone network, simplifying moves, adds, or changes.

However, Cisco ER can only automatically track telephone movement for certain types of phones, and for phones attached to certain types of switch ports. See "Network Hardware and Software Requirements" section for a list of these phones and switches.

To achieve full automation, update your switches to supported models or software versions, and replace your telephones with supported models.

Preparing Your Staff for Cisco Emergency Responder

Cisco Emergency Responder (Cisco ER) does not replace your existing emergency procedures. Instead, Cisco ER is a tool you can use to augment those procedures. Before deploying Cisco ER, consider how it fits into your procedures and how you want to use the Cisco ER system's capabilities.

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When someone makes an emergency call, Cisco ER notifies the assigned onsite alert (security) personnel (your emergency response teams) of the location of the caller. This information is, for the most part, the ERL name. Consider working with your emergency response teams to come up with an ERL naming strategy that will help them respond quickly to emergencies. Incorporating building names, floor numbers, and other readily understood location information in the name are the types of things to consider.

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Cisco ER lets you define three types of administrative user, so you can divide responsibilities for overall Cisco ER system administration, network administration, and ERL administration. The skills and knowledge necessary for these tasks might be rare to find in one person. Consider dividing Cisco ER configuration responsibilities according to these skills.

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The routing of emergency calls, and the transmission of the correct ALI, is only as good as the reliability of the ALI definitions you submit to your service provider and in the stability of your network topology. Ensure that your ERL administrator understands the importance of keeping the ALI data up-to-date, and that your network administrator understands the importance of maintaining a stable network. See the "Data Integrity and Reliability Considerations" section for more information about maintaining data integrity.

Deploying Cisco Emergency Responder

These topics describe deployment models for various types of networks. You can use these examples as modules, combining them to form a larger, more complex network.

Deploying Cisco Emergency Responder in One Main Site with One PSAP

To support a simple telephony network consisting of a single Cisco Unified Communications Manager cluster, install two Cisco ER servers and configure one server as the Publisher and the other server as a Subscriber pointing to the Publisher.

Because there is only one local PSAP, you only need one gateway to the service provider's network, although capacity planning for your telephony network might require more than one gateway. Configure all route patterns to use this gateway.

Figure 1-4 shows how Cisco Emergency Responder (Cisco ER) fits into a simple telephony network where you have a single Cisco Unified Communications Manager cluster.

Deploying Cisco Emergency Responder in One Main Site with Two or More PSAPs

Figure 1-5 illustrates the Cisco Emergency Responder (Cisco ER) configuration if you have one main site that is served by two or more PSAPs. This example assumes you have one Cisco Unified Communications Manager cluster. If you have more than one, the setup is logically the same as the one discussed in the "Deploying Cisco Emergency Responder In Two Main Sites" section.

To support this type of network, install two Cisco ER servers and configure one server as the Publisher and the other server as a Subscriber pointing to the Publisher.

Because there are two PSAPs serving the location, you probably need more than one gateway connecting to different parts of the service provider's network. However, this depends on the layout of the service provider's network: you might only need one gateway if the PSAPs are served by a selective router that can intelligently route emergency calls to more than one PSAP. Consult with your service provider to determine the requirements for your buildings. In this example, we assume you will need two gateways. Of course, capacity planning for your telephony network might require more than one gateway for each link.

After setting up the gateways to correctly connect to the service provider's network, configure all route patterns used in Building A ERLs to use gateway A, and all route patterns used in Building B ERLs to use gateway B. As phones move between buildings, Cisco ER dynamically updates their ERLs so that emergency calls get routed out of the desired gateway.

Deploying Cisco Emergency Responder In One Main Site with Satellite Offices

Figure 1-6 illustrates the Cisco Emergency Responder (Cisco ER) configuration if you have one main site that serves one or more satellite offices, that is, where the phones in the satellite office are run from the Cisco Unified Communications Manager cluster on the main site. If the satellite office has its own Cisco Unified Communications Manager cluster, see the "Deploying Cisco Emergency Responder In Two Main Sites" section.

To support this type of network, install two Cisco ER servers and configure one server as the Publisher and the other server as a Subscriber pointing to the Publisher. Install both servers in the main office.

Most likely, there are separate PSAPs serving the main (Columbus) and satellite (Chillicothe) offices. Thus, you probably need more than one gateway connecting to different parts of the service provider's network (you might even have different service providers). However, this depends on the layout of the service provider's network: you might only need one gateway if the PSAPs are served by a shared switch. Consult with your service provider to determine the requirements for your buildings. In this example, we assume you will need two gateways. Of course, capacity planning for your telephony network might require more than one gateway for each link.

After setting up the gateways to correctly connect to the service provider's network, configure all route patterns used in Columbus's ERLs to use gateway COL, and all route patterns used in Chillicothe's ERLs to use gateway CHIL. As phones move between sites, Cisco ER dynamically updates their ERLs so that emergency calls get routed out of the desired gateway.

You might also need to tune SNMP performance to account for the WAN link. Cisco ER must do SNMP queries of the remote site's switches to track phone movements there, and you might run into SNMP time-out problems if you do not allow enough time or retries to make a successful SNMP query. See the "Configuring the SNMP Connection" section on page 5-39 for more information.

Tip

If the satellite office is small (fewer than 50 phones) and you are using survivable remote site telephony (SRST), it is probably easier to support emergency calls directly by configuring the gateway in the remote office to send 911 calls to an FXO port that has a CAMA trunk to the local PSAP rather than to Cisco ER in the main office.

Deploying Cisco Emergency Responder In Two Main Sites

Figure 1-7 illustrates the Cisco Emergency Responder (Cisco ER) configuration if you have two (or more) main sites, each served by a separate PSAP.

You can adapt this example to a more complex setup by combining this discussion with these examples:

Most likely, there are separate PSAPs serving your main offices. In this example, Chicago and New York use different PSAPs. You need at least one gateway in Chicago, and one in New York, to connect to different parts of the service provider's network (you might even have different service providers). Consult with your service provider to determine the requirements for your buildings. Of course, capacity planning for your telephony network might require more than one gateway in each site.

After setting up the gateways to correctly connect to the service provider's network, configure all route patterns used in Chicago's ERLs to use gateway CHI, and all route patterns used in New York's ERLs to use gateway NYC.

To enable phone movement between Chicago and New York, you must also configure an inter-cluster trunk to link the Cisco Unified Communications Manager clusters, and create an inter-Cisco ER group route pattern so that Cisco ER can transfer calls between Cisco Unified Communications Manager clusters served by separate Cisco ER groups. The "Creating Route Patterns for Inter-Cisco Emergency Responder-Group Communications" section goes into more details about how Cisco ER handles phone movement in this situation.

As phones move between sites, Cisco ER dynamically updates their ERLs so that emergency calls get routed out of the desired gateway. However, if the WAN link becomes unavailable, Cisco ER can not track phone movement between the sites.

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