Technical Summary
This memo defines the Session Description Protocol (SDP). SDP is intended
for describing multimedia sessions for the purposes of session announcement,
session invitation, and other forms of multimedia session initiation.
In particular, this document provides a new version of SDP that incorporates
fixes and extensions that have been designed in the MMUSIC WG since the
publication of the original SDP specification, RFC2327. This document is not
SDPng, which fundamentally re-examines the problem space of SDP and arrives
at a new solution. Rather, this document collects increment fixes to SDP
that are critical to its proper operation, and merit inclusion in the core
standard.
Working Group Summary
The MMUSIC working group supported publication of this document.
Protocol Quality
This document was reviewed by Allison Mankin and Jon Peterson.
RFC-Editor Note
Please append to the start of Section 9:
OLD:
9. SDP Grammar
NEW:
9. SDP Grammar
This section provides a grammar for SDP. It uses a variant of
ABNF [4]. In this variant, contrary to section 2.3 of [4], strings
are *not* case-insensitive, and must match exactly the case specified.
Security Considerations, last paragraph:
OLD:
Use of the "k=" field poses a significant security risk, since it
conveys session encryption keys in the clear. SDP MUST NOT be used
to convey key material, unless it can be guaranteed that the channel
over which the SDP is delivered is both private and authenticated.
NEW:
Use of the "k=" field poses a significant security risk, since it
conveys session encryption keys in the clear. SDP MUST NOT be used
to convey key material, unless it can be guaranteed that the channel
over which the SDP is delivered is both private and authenticated.
Moreover, the k= line provides no way to indicate or negotiate
cryptographic key algorithms, and as it provides for only a single
symmetric key, rather than separate keys for confidentiality and
integrity, its utility is severely limited. Use of the k= line is
NOT RECOMMENDED, and any usage of the k= line MUST address these
shortcomings.