Sdp Session Description Overview - Juniper NETWORK AND SECURITY MANAGER 2010.4 - CONFIGURING SCREENOS DEVICES GUIDE REV 01 Manual

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SDP Session Description Overview

SDP SDP Format
c= for connection This field can appear at the session or
information media level. It displays in this format:
c=<network type><address
type><connection address>
m= for media This field appears at the media level and
announcement contains the description of the media. It
displays in this format:
m=<media><port><transport><fmt list>
288
Select IP Attack Protection and specify a Timeout if you want IP attack protection
7.
to be enabled.
Click OK to apply your settings.
8.
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
SDP Session Description Overview on page 288
An SDP session description is text-based and consists of a set of lines. It can contain
session-level and media-level information. The session-level information applies to the
whole session, while the media-level information applies to a particular media stream.
An SDP session description always contains session-level information, which appears
at the beginning of the description, and might contain media-level information, which
comes after.
NOTE: In the SDP session description, the media-level information begins
with the m= field.
Of the many fields in the SDP session description, two are particularly useful to the SIP
ALG because they contain Transport Layer information. The two fields are the following:
If the destination IP address is a unicast IP address, the SIP ALG creates pinholes using
the IP address and port numbers specified in the media description field m=.
In this release of ScreenOS, the security device opens ports only for RTP and Real-Time
Control Protocol (RTCP). Every RTP session has a corresponding RTCP session.
Description
Currently, the security device supports only "IN" (for Internet)
as the network type, "IP4" as the address type, and a unicast
IP address or domain name as the destination (connection) IP
address.
NOTE: Generally, the destination IP address can also be a
multicast IP address, but ScreenOS does not currently support
multicast with SIP.
Currently, the security device supports only " audio" as the
media and "RTP" as the Application Layer transport protocol.
The port number indicates the destination (not the origin) of
the media stream. The format list (fmt list) provides information
on the Application Layer protocol that the media uses.
Copyright © 2010, Juniper Networks, Inc.