Voice Over Internet Protocol; Chapter 9 Voice Over Internet Protocol; Sccp Support In Screenos Devices Overview - Juniper NETWORK AND SECURITY MANAGER 2010.4 - CONFIGURING SCREENOS DEVICES GUIDE REV 01 Manual

CHAPTER 9

Voice Over Internet Protocol

SCCP Support in ScreenOS Devices Overview

Copyright © 2010, Juniper Networks, Inc.
This chapter presents an overview of the Skinny Client Control Protocol (SCCP)
Application Layer Gateway (ALG) and lists the firewall security features of the
implementation.
This chapter contains the following topics:
SCCP Support in ScreenOS Devices Overview on page 279
Configuring SCCP ALG in ScreenOS Devices (NSM Procedure) on page 280
SIP ALG Overview on page 281
SIP Request Methods Supported in ScreenOS Devices on page 282
Types of SIP Response Classes Supported in ScreenOS Devices on page 284
ALG Overview on page 286
Configuring SIP ALG in ScreenOS Devices (NSM Procedure) on page 287
SDP Session Description Overview on page 288
Pinhole Creation in ScreenOS Devices Overview on page 289
Session Inactivity Timeout in ScreenOS Devices Overview on page 290
Skinny Client Control Protocol (SCCP) is supported on security devices in Route,
Transparent, and Network Address Translation (NAT) modes. SCCP is a binary-based
Application-Layer protocol used for voice over IP (VoIP) call setup and control. In the
SCCP architecture, a Cisco H.323 proxy, known as the CallManager, does most of the
processing. IP phones, also called end stations, run the Skinny client and connect to a
primary (and, if available, a secondary) CallManager over TCP on port 2000 and register
with the primary CallManager. This connection is then used to establish calls coming to
or from the client.
The SCCP ALG supports the following features:
Call flow—Allows calls from a Skinny client, through the CallManager, to another Skinny
client.
Seamless failover—Switches over all calls in process to the standby firewall during
failure of the primary firewall.
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