Configure Intercluster Lookup Service

Intercluster Lookup Service Overview

The Intercluster Lookup Service (ILS) allows you to create networks of remote Cisco Unified Communications Manager clusters. When you configure ILS on multiple clusters, it updates Cisco Unified Communications Manager with the current status of remote clusters in the ILS network.

In Cisco Unified CM Administration, you can configure ILS on a pair of clusters and then join those clusters to form an ILS network. ILS allows you to join additional clusters to the network without having to configure the connections between each cluster.

An ILS network comprises the following components:
  • Hub clusters
  • Spoke clusters
  • Global dial plan imported catalogs

Hub Clusters

Hub clusters form the backbone of an ILS network. Hub clusters exchange ILS updates with the other hub clusters in the ILS network, and then relay that information to and from their spoke clusters.

When a new hub cluster registers to another hub cluster in an existing ILS network, ILS automatically creates a full mesh connection between the new hub cluster and all the existing hub clusters in the ILS network.

Spoke Clusters

A spoke cluster connects to the hub cluster in an ILS network to relay ILS updates to and from the rest of the ILS network. Spoke clusters contact only their local hub cluster and never directly contact other hub clusters or other spoke clusters.

Global Dial Plan Imported Catalogs

To provide URI dialing compatibility with third-party systems, you can manually import a third-party directory URI or +E.164 number catalog from a CSV file into any hub cluster in the ILS network. ILS maintains the imported catalog and replicates that catalog out to the other clusters in the network. You can dial one of the third-party directory URIs or +E.164 numbers catalog from any server in the ILS network.

ILS Networking Capacities

Following are recommended capacities to keep in mind when planning an ILS network:

  • ILS networking supports up to 10 hub clusters with 20 spoke clusters per hub, up to a 200 total cluster maximum. A hub and spoke combination topology is used to avoid many TCP connections created within each cluster.

  • There may be a performance impact with utilizing your hub and spoke clusters at, or above, their maximums. Adding too many spoke clusters to a single hub creates extra connections that may increase the amount of memory or CPU processing. We recommend that you connect to a hub cluster with no more than 20 spoke clusters.

  • ILS networking adds extra CPU processing to your system. The CPU utilization and sync time is dependent on the number of records that are being synced across the cluster. When planning your hub and spoke topology, make sure that your hub clusters have the CPU to handle the load.


Note
These recommendations are based on system testing and taking resource utilization into account. Although the system does not prevent you from exceeding these recommendations, by doing so you would risk the overutilization of resources. Cisco recommends the above capacities for optimal performance.

ILS Configuration Task Flow

Procedure

  Command or Action Purpose

Step 1

Activate Intercluster Lookup Service

Activate Intercluster Lookup Service to configure cluster IDs and remote clusters.

Step 2

Configure Cluster IDs

Provide a unique identifier for each cluster in the ILS network.

Step 3

Configure Remote Clusters

Configure remote clusters in the ILS network.

Step 4

To activate ILS on the various clusters, complete the following tasks:

Activate ILS on the hub cluster and spoke cluster in the ILS network.

Note

 

You must configure each cluster in your ILS network as either a hub cluster or a spoke cluster.

Step 5

(Optional) Configure authentication between your cluster. Select one of the following procedures:

Use TLS authentication between clusters in the ILS network.

Use password authentication between remote clusters in the ILS network.

Use TLS and password authentication to setup a ILS network using common Certificate Authority (CA) signed certificates without exchanging self-signed certificates between clusters.

Step 6

Enable ILS Support for Global Dial Plan Replication

(Optional) Enable ILS support for Global Dial Plan Replication to share dial plan information between participating ILS enabled clusters.

Step 7

Import Catalogs in ILS Network

(Optional) To provide URI dialing compatibility with third party systems, you can manually import a third party directory URI or +E.164 number catalog from a csv file into any hub cluster in the ILS network.

Activate Intercluster Lookup Service

You must activate the Intercluster Lookup Service to configure Cluster IDs and Remote Clusters.

Procedure

Step 1

From Cisco Unified Serviceability, choose Tools > Service Activation.

Step 2

From the Server drop-down list, choose the node on which you want to activate Cisco Intercluster Lookup Service, and then click Go.

Step 3

Check the Cisco Intercluster Lookup Service check box.

Step 4

Click Save.

What to do next

Configure Cluster IDs

Configure Cluster IDs

You must configure a unique cluster ID for each cluster in the ILS network. You must also ensure that you have a unique peer ID. The clusters use this unique cluster ID and peer ID when they exchange status messages.

For example, if you have an existing ILS network of four Cisco Unified Communications Manager clusters and you want to add an additional cluster, you can configure ILS on the new cluster and then register that cluster to any hub cluster in the existing ILS network. ILS automatically informs the new cluster of all clusters in the existing network.

Each cluster in an ILS network exchange and update messages, called peer info vectors, that are designed to inform remote clusters of the status of each cluster in the network. The update messages contain information about the known clusters in the network, including:

  • Cluster IDs

  • Peer IDs for the publisher

  • Cluster descriptions and versions

  • Fully Qualified Domain Name (FQDN) of the host

  • IP addresses and host names for the cluster nodes that have ILS activated

Perform the following procedure to configure a unique identifier for each cluster in the network.

Before you begin

Activate Intercluster Lookup Service

Procedure

Step 1

Log in to the Unified Communications Manager publisher node.

Step 2

In Cisco Unified Communications Manager Administration, choose System > Enterprise Parameters.

Step 3

In the Enterprise Parameters Configuration window Cluster ID field, enter a name of the cluster that you want to configure in your network.

You can enter up to 50 characters. You can enter alphanumeric characters, period (.), and hyphen (-). The default value is StandAloneCluster.

Step 4

Click Save.

What to do next

Configure Remote Clusters

Configure Remote Clusters

Perform the following steps to configure remote clusters in the ILS network.

Before you begin

Configure Cluster IDs

Procedure

Step 1

In Cisco Unified Communications Manager Administration, choose Advanced Features > Cluster View.

Step 2

In the Find and List Remote Clusters window, choose any previously created remote cluster.

Step 3

From the Remote Cluster Service Configuration window, check the appropriate check box to configure services such as Extension Mobility Cross Cluster, TFTP, and RSVP Agent for remote clusters.

What to do next

Perform one of the following procedures:

Activate ILS on the Hub Cluster

Configure each cluster in your ILS network as either a hub cluster or a spoke cluster. Each ILS network must have at least one hub cluster. You can connect a hub cluster to other hub clusters, or you can configure a hub cluster as the only hub cluster in the network. In addition, you can connect a hub cluster to multiple spoke clusters, or you can configure the hub cluster with no spoke clusters.

Perform the following procedure to activate the ILS on the hub cluster in the ILS network.

Before you begin

Configure Remote Clusters

Procedure

Step 1

Log in to the Cisco Unified Communications Manager publisher node.

Step 2

Choose Advanced Features > ILS Configuration.

Step 3

In the ILS Configuration window, in the Role drop-down list, select Hub Cluster and click Save.

Note

 

To remove a specific cluster in the ILS network, in the ILS Configuration window, in the Role drop-down list, select Standalone and click Save.

Step 4

In the ILS Configuration Registration pop-up window, leave the Registration Server text box empty and click OK.

What to do next

Activate ILS on the Spoke Cluster

A spoke cluster connects to the hub cluster in an ILS network to relay ILS updates to and from the rest of the ILS network. Follow this procedure to activate ILS on the spoke cluster.

Before you begin

Procedure

Step 1

Log in to the Unified Communications Manager publisher node.

Step 2

In Cisco Unified CM Administration, choose Advanced Features > ILS Configuration.

Step 3

From the Role drop-down list, select Spoke Cluster and click Save.

Step 4

In the ILS Configuration Registration popup window, enter the IP address or fully qualified domain name of the publisher node for an existing hub cluster in your ILS network in the Registration Server text box and click OK.

Step 5

Confirm that your ILS network is configured by viewing the network in the ILS Clusters and Global Dial Plan Imported Catalogs section.

When the full network appears, your ILS network is configured for cluster discovery.

What to do next

Perform any of these optional procedures:

Enable TLS Authentication Between Clusters

(Optional) Use this procedure for the TLS authentication to encrypt communications between remote clusters in the ILS network:

Before you begin

To use Transport Layer Security (TLS) authentication between clusters, you must exchange Tomcat certificates between the publisher node of each cluster in the ILS network. From Cisco Unified Operating System Administration, use the Bulk Certificate Management feature to:
  • export certificates from the publisher node to a central location, for each cluster in your network
  • consolidate exported certificates from any publisher node server in your ILS network
  • import certificates into the publisher node for each cluster in your network

Note

For more information about enabling TLS Authentication Between Clusters, see the Administration Guide for Cisco Unified Communications Manager at http://www.cisco.com/c/en/us/support/unified-communications/unified-communications-manager-callmanager/products-maintenance-guides-list.html.

Procedure

Step 1

Log in to the Unified Communications Manager publisher node.

Step 2

In Cisco Unified CM Administration, choose Advanced Features > ILS Configuration.

Step 3

In the ILS Configuration window, check the Use TLS Certificates check box under ILS Authentication.

Step 4

Click Save.

What to do next

Perform any of these optional procedures:

Enable Password Authentication Between Clusters

(Optional) To use password authentication between remote clusters, you must assign a password for all communications between clusters in your ILS network.

Procedure

Step 1

Log in to the Unified Communications Manager publisher node.

Step 2

In Cisco Unified CM Administration, choose Advanced Features > ILS Configuration.

Step 3

In the ILS Configuration window, check the Use Password check box under ILS Authentication.

Step 4

Enter a password in the Use Password text box.

Note

 
You must configure all clusters in your network with the same password.

Step 5

Re-enter the password in the Confirm Password text box.

Step 6

Click Save.

What to do next

Perform any of these optional procedures:

Enable TLS with Password Authentication Between Clusters

Before you begin

To use Transport Layer Security (TLS) and password authentication without exchanging certificates between clusters, you must upload the certificate authority root certificates to the Tomcat trust and get the Tomcat certificate signed by the certificate authority root certificate. The certificate is then imported back on the same cluster. The clusters can be connected to Intercluster Lookup Service (ILS) network once the certificates are uploaded with the same password for all the clusters.


Note

For more information about enabling TLS Authentication Between Clusters, see the Administration Guide for Cisco Unified Communications Manager at http://www.cisco.com/c/en/us/support/unified-communications/unified-communications-manager-callmanager/products-maintenance-guides-list.html.

Procedure

Step 1

Log in to the Cisco Unified Communications Manager publisher node.

Step 2

In Cisco Unified CM Administration, choose Advanced Features > ILS Configuration.

Step 3

In the ILS Configuration window, check the Use TLS Certificates check box under ILS Authentication..

Step 4

In the ILS Configuration window, check the Use Password check box under ILS Authentication.

Step 5

Enter a password in the Use Password text box.

Note

 
You must configure all clusters in your network with the same password.

Step 6

Re-enter the password in the Confirm Password text box.

Step 7

Click Save.

What to do next

(Optional)Enable ILS Support for Global Dial Plan Replication

Enable ILS Support for Global Dial Plan Replication

(Optional) To enable ILS support for Global Dial Plan Replication in the local cluster, follow this procedure:

Procedure

Step 1

Log in to the Unified Communications Manager publisher node.

Step 2

In Cisco Unified Communications Manager Administration, choose Advanced Features > ILS Configuration.

Step 3

In the ILS Configuration window, check the Exchange Global Dial Plan Replication Data with Remote Clusters check box.

Step 4

In the Advertised Route String text box, enter a route string for the local cluster.

Step 5

Click Save.

Note

 

When advertising URI patterns (user@domain), in the SIP Profile Configuration window, make sure that the Dial String Interpretation field is set to Always treat all dial strings as URI addresses to prevent the devices to dial URI learned patterns with only numbers in the user section as Directory Number patterns. Alternatively, you can advertise only URI patterns with text strings in the user section through ILS.

What to do next

Import Catalogs in ILS Network

Import Catalogs in ILS Network

(Optional) To provide URI dialing compatibility with third party systems, you can manually import a third party directory URI or +E.164 number catalog from a csv file into any hub cluster in the ILS network. To Import Catalogs in the ILS network, follow this procedure:

Procedure

Step 1

In Cisco Unified Communications Manager Administration, choose Call Routing > Global Dial Plan Replication > Imported Global Dial Plan Catalogs.

Step 2

In the Find and List Imported Global Dial Plan Catalogs window, click Add New.

Step 3

Enter a Name, Description and Route String for the catalog and click Save.

Step 4

In Cisco Unified Communications Manager Administration, choose Bulk Administration > Upload/Download Files.

Step 5

Click Choose and select the CSV file that you want to import for the catalogs.

Step 6

From the Select the Target drop-down list, choose Imported Directory URIs and Patterns.

Step 7

From the Select Transaction Type drop-down list, choose Insert Imported Directory URIs and Patterns.

Step 8

Click Save.

ILS Interactions and Restrictions

ILS Interactions

Table 1. ILS Interactions

Feature

Interaction

Cluster discovery

ILS cluster discovery allows Cisco Unified Communications Manager clusters to learn dynamically about remote clusters without the need for an administrator to manually configure connections between those clusters.

Each cluster in an ILS network exchange update messages, called peer info vectors, that are designed to inform remote clusters of the status of each cluster in the network. The update messages contain information about the known clusters in the network, including:

  • Cluster IDs
  • Cluster descriptions and versions
  • Fully qualified domain name of the host
  • IP addresses and hostnames for the cluster nodes that have ILS activated

The ILS cluster discovery feature automatically populates the list of remote clusters that can be viewed in Cisco Unified CM Administration by choosing Advanced Features > Cluster View. From this window, you can configure services such as Extension Mobility Cross Cluster, TFTP, and RSVP Agent for remote clusters.

Note

 

A fully qualified domain name of the remote cluster, as seen in the Cluster View, must be DNS resolvable for ILS discovery to work.

Global Dial Plan Replication

When Global Dial Plan Replication is enabled across an ILS network, remote clusters in an ILS network share global dial plan data, including the following:

  • Directory URIs
  • Alternate numbers
  • Alternate number patterns
  • Route strings
  • PSTN failover numbers

Block Inbound Calls

To block Inbound calls based on calling party number in an ILS-based network, you must include the SIP route pattern's partition in the calling party's CSS. For example, if the call originates from SIP Trunk then SIP trunk inbound CSS must have SIP route pattern's partition.

ILS Restrictions

Table 2. ILS Restrictions

Restriction

Description

ILS Service

The ILS Service runs only on the Unified Communications manager publisher node.

Clusters

A hub cluster can have many spokes but, a spoke cluster can have only one hub cluster.

ILS Network

You cannot connect a third-party call control system into an ILS network.

Cluster Import

You can import a third-party catalog into a hub cluster only.

Duplicated URI

If a learned ILS cluster contains duplicated URIs from a different remote cluster and when a call is placed to that URI, it will be routed to the cluster whose URI has been learned and inserted into the database first.

Database Replication Status

Although the Global dial plan data is exchanged successfully on the ILS Network, an ILS receiving cluster will not write learned information into the database until it completes its database replication status.

Import

For imported third-party directory URIs and patterns, the CSV file format must match the exact syntax as shown in the administration window sample file otherwise, the import fails.

ILS Hub

When adding an additional hub cluster into the ILS network ensure to verify the following conditions are met for the primary ILS hub node:

  • Cluster ID is unique across all the hub nodes in the ILS cluster.

  • Fully Qualified Domain Name (FQDN) is configured.

  • UDS and EM services are running on the all of the hub nodes in the ILS cluster

  • DNS primary and reverse resolution are working fine.

  • Import consolidated Tomcat certificates from all the hub nodes.

Else, the "version" information will not get displayed in the Find and List Remote Clusters window even after rebooting the clusters or correcting the errors. The workaround is to remove the hub cluster from the ILS network, comply with the above requirements and add the hub cluster back into the ILS network.