AudioCodes MEDIAPACK VERSION 6.2 - Manual (Page 19)

Version 6.2 19 December 2010
SIP Release Notes 1. What's New in Release 6.2
3. SDP Offer/Answer Negotiation upon Modified Session:
Product
MP-11x MP-124
Mediant 600 Mediant 1000
Mediant 800 MSBG Mediant 1000 MSBG
Mediant 2000
Mediant 3000/TP-6310 Mediant 3000 HA/TP-6310
Mediant 3000/TP-8410 Mediant 3000 HA/TP-8410
Management Protocol
Web INI SNMP EMS CLI
This feature enables the flexibility of ignoring a new SDP re-offer (from the media
negotiation perspective) in certain scenarios (such as session expires). According to
RFC 3264, once an SDP session is established, a new SDP offer is considered a new
offer only when the SDP origin value is incremented. In scenarios such as session
expires, SDP negotiation is irrelevant and thus, the origin field is not changed.
Even though some SIP devices don’t follow this behavior and don’t increment the
origin value even in scenarios where they want to re-negotiate, the device up till now
re-negotiated regardless of the origin field value. Since this caused problems in certain
scenarios, this feature resolves this by assuming that the remote party operates
according to RFC 3264, and in cases where the origin field is not incremented, the
device does not re-negotiate SDP capabilities.
This feature offers the following options:
• The device negotiates any new SDP re-offer, regardless of the origin field
(default).
• The device negotiates only an SDP re-offer with an incremented origin field.
This feature is configured using the new parameter, EnableSDPVersionNegotiation.