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Cisco H.323 Signaling Interface User Guide, Release 4.1
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Cisco H.323 Signaling Interface Overview
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Installing and Configuring Cisco HSI Software
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Provisioning the Cisco HSI
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Managing the Cisco HSI
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Troubleshooting Cisco HSI Alarms
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MML User Interface and Command Reference
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Skeleton Configuration File
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Example of an HSI Configuration File
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E-ISUP Name-to-Cause Value Lookup
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E-ISUP Cause Value-to-Name Lookup
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H.323 Name-to-Cause Value Lookup
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H.323 Cause Value-to-Name Lookup
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Table Of Contents
Cisco H.323 Signaling Interface Overview
New Features in Cisco HSI Release 4.1
Cisco H.323 Signaling Interface Overview
Introduction
This chapter provides an overview of the Cisco H.323 Signaling Interface (HSI) system and subsystems and contains the following sections:
Cisco HSI Overview
The Cisco HSI adds an H.323 interface to the Cisco Public Switched Telephone Network (PSTN) Gateway (PGW 2200). This interface allows calls to be established between the PSTN and an H.323 network (see Figure 1-1).
The Cisco HSI provides the following services:
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Translation of signaling protocols for establishing, controlling, and releasing calls
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The Cisco HSI does not operate in an active/standby configuration and, therefore, does not provide the same level of redundancy as the PGW 2200, which is configured as active/standby. We therefore recommend that you use enough HSI nodes to support the number of simultaneous calls plus one. This ensures (Trunk Group Caveats dependant) that, if one HSI fails, the calls are still adequately supported by the remaining active HSIs.
Figure 1-1 Cisco HSI System Overview
PGW 2200
The PGW 2200 consists of the hardware and software that perform the signaling and call control tasks (such as digit analysis, routing, and circuit selection) and seamlessly switch calls from the PSTN through to the IP network.
IP Network
The purpose of the Cisco HSI is to enable the PGW 2200 to interoperate with the H.323 network.
Cisco HSI System Description
The Cisco HSI system has two subsystems (see Figure 1-2):
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Figure 1-2 Cisco HSI Subsystems
OAM Subsystem
The OAM subsystem provides the following services:
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Call Control Subsystem
The call control subsystem provides the following services:
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RUDP
RUDP transports the E-ISUP messages between the PGW 2200 and the Cisco HSI.
RUDP is a Cisco proprietary, connection-oriented, packet-based transport protocol.
RADVision H.323
The Cisco HSI 4.1 release uses the RADVision 4.1 H.323 stack. The HSI uses the H.225 (Q.931 and registration, admission, and status [RAS] protocol) and H.245 protocols to implement the H.323 gateway signaling function.
RADVision H.323 enables the creation of real-time voice H.323 calls over IP networks.
E-ISUP
E-ISUP is a proprietary Cisco protocol based on ISUP. E-ISUP is used for inter-PGW 2200 call control. E-ISUP uses a subset of ISUP messages. The main differences between ISUP and E-ISUP are as follows:
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The Cisco HSI provides a conversion between the E-ISUP call control protocol originating from the PGW 2200 and the H.323 call control protocol originating from the IP network (see Figure 1-1).
New Features in Cisco HSI Release 4.1
The features introduced in the Cisco HSI 4.1 release are:
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Operational Environment
This section provides operational environment requirements for the Cisco HSI.
Hardware Requirements
The hardware requirements for the Cisco HSI are documented in the Cisco Media Gateway Controller Hardware Installation Guide. See the section "Cisco MGC Host Platforms" in Chapter 1.
Software Requirements
The software requirements for the Cisco HSI are documented in the Cisco Media Gateway Controller Software Release 9 Installation and Configuration Guide.
Security
The application does not directly provide security features. All security must be implemented at the UNIX level.
Cisco HSI Recovery
The Cisco HSI automatically restarts the main application process if that process terminates.
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Cisco HSI System Limitations
The Cisco HSI does not implement security features.
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