Cisco SCCP End Points configuration in Cyara Voice Gateway

Cyara Voice Gateway/Endpoints Documentation for Cisco SCCP

Overview

Cyara can perform endpointing and agent emulation via a standalone program called Cyara Voice Gateway. Cyara Voice Gateway’s main function is as an endpoint that performs SIP registrations and protocol translation. Its secondary function is as a back-to-back user agent/network isolator. Cyara Voice Gateway runs as a Windows Service and is configured and monitored via a web interface.

When a call comes into the PABX, an Originate message is sent to Cyara Voice Gateway, which then translates that into the corresponding SIP messaging (an Invite) for the Cyara Call Engine.

Cyara Voice Gateway Scenarios

The configuration of the Cyara Voice Gateway service is very complex, requiring extensive expertise in the H.323, SIP, and Skinny protocols, in addition to knowledge of how these protocols interwork. In addition, the configuration of the Cyara Voice Gateway server is dependent on the customer environment it is deployed in. The number of options possible is extensive and difficult to get right. A single error in configuration could cost hours in investigation and remedy.

To simplify the process of deployment, three typical scenarios have been identified where an Cyara Voice Gateway server may be deployed with a Cyara Platform. By concentrating on the configuration necessary for these typical deployments, the number of options to consider can be reduced to a manageable set.

The Cyara Voice Gateway server is used in conjunction with the Cyara Platform to provide a H.323 capability, a SCCP capability, or SIP-to-SIP interworking as a Back-to-Back User Agent (B2BUA).

Media Configuration

For each of the different scenarios in which the Cyara Voice Gateway server can be used with the Cyara Platform, there are some common requirements that must be met.

The Cyara Voice Gateway server is a very flexible application and supports a large and diverse number of codecs used to encode/decode the call media. Not all of these codecs are supported by the Cyara Platform. As a result, some of these Cyara Voice Gateway server types must not be selected when a call is established, because the call will not have any audio.

To prevent an unsupported media type being negotiated for a call, the Preferred media and removed media types will need to be set up on the Cyara Voice Gateway server. This will ensure only supported codecs are offered and not removed as part of the media negotiation.

Media types supported by the Cyara Platform are:

711 64k μ-Law
711 64k A-Law
729
729A
729B
729AB
723.1
User Input/RFC2833

If an endpoint does not support the codecs supported by the Cyara Platform, the call will fail to be established.

When deploying the Cyara Voice Gateway server, there are options on how to route the call media. The options are to forward media, transcode media, or bypass media.

When the Cyara Voice Gateway server forwards media, it means that all media payloads will be sent to the Cyara Voice Gateway server first, which will redirect them to the endpoint. This requires the Cyara Voice Gateway server to handle all call signalling and all media streaming.

When the Cyara Voice Gateway server transcodes media, it not only receives all the media payloads from either endpoint, but it translates one media type into another media type. This is very processor-intensive and requires translation of every packet going in both directions of the call.

When the Cyara Voice Gateway server is set to bypass media, it means that the call media is set to go directly from one endpoint to the other endpoint of the call. In this configuration, the Cyara Voice Gateway server does not participate in transferring media payloads for the call.

The last option must always be selected for any Cyara Voice Gateway server deployment scenario.

Cyara SCCP Interworking

Registering endpoints as SCCP (or Skinny) endpoints is a very different than with H.323 endpoints. For ease, the Cyara Voice Gateway server handles the details of registering the endpoints and converting the SCCP call signalling and media to SIP.

Configuring the Cyara Voice Gateway Service

You may need to check the fields on the Cyara Voice Gateway service web interface (:1719) for troubleshooting. Note that many of the parameters on this page will have been pre-filled during installation.

On the main page of the web interface, click on System Parameters. The screen below is shown:

On the main page of the web interface, click on System Parameters. The screen below is shown:
Media Transfer Mode: ensure that Bypass is selected. The Forward and Transcode modes should never be selected.
Preferred Media: you may need to modify this field. **But it might get passed down to Call Engine and that might not support the Cyara Voice Gateway-preferred media**.
Removed Media: this remove codecs from negotiation that should not be passed through the system. This is done to minimize load and complication.
Disable In-band DTMF Detect: Ensure this is unchecked to minimize load.
H323 Aliases: there must always be a dummy entry in this field. Do not delete.
Remote Gatekeeper Address: there must always be a dummy entry in this field. Do not delete.
Remote Gatekeeper Interface: this field can have a comma separated list of IP addresses, or <<ip4>> (this may change) to wildcard, which tells Cyara Voice Gateway to use all IPV4 interfaces this machine has. **This is not compulsory, but some customers may want to use it to have many different IP addresses. You will also need to configure multiple aliases in the OS.**
Remote Gatekeeper Password: if you are configuring as an extension in Avaya PABX, the configuration Type must be H.323.
Note: the security code is important here; all phones must have that same passcode.
Remote Gatekeeper Alias Limit: this reduces the load on Cyara Voice Gateway/Endpoints. The number of extensions registered per registration request (RRQ) for Avaya cannot be greater than 12; the recommended limit is 1 to maintain stability.
SIP Local Registrar Domains: this must match what is contained in the Call Engine’s registration.csv file.
SCCP Device Type (For Cisco Skinny environments): This is the Cisco ID of the handset/softphone being emulated. All devices inside Cisco Call Manager must be configured as the same type to match the code in this field (all endpoints must be the same type because Cyara does not emulate all of the features of a phone).
SCCP Device Names (For Cisco Skinny environments): This is the name or range of names of our emulated endpoint devices. Cisco Skinny phones register using their device name, which is typically the letters 'SEP' followed by the MAC address of the phone. For our emulation, the device names can be configured as anything so long as it follows a sequential numbering pattern (e.g., ‘Cyara0001’, ‘Cyara0002’ etc). To specify a range, add a '..' between the number ranges (e.g 'Cyara0001..0499')
<screen shots from Avaya and Cisco from worked examples>
SCCP Server: This is the IP Address of the customer’s Cisco ‘Subscriber’ server that Cyara’s Skinny endpoints will register with.
SCCP Simulated Audio File (For Cisco Skinny environments): this is related to call recording for Cisco with DMS (Cyara Voice Gateway emulates agent’s phone like the Cisco DMS). Cyara Professional Services would provide and install a reference file for the Call Recording in this field.
Routes: this is where the translation takes place. It will be done in template form during the installation.