150 likes | 282 Views
FEC framework Configuration Signaling. draft-ietf-fecframe-config-signaling-02.txt IETF 76 . Rajiv Asati. Agenda. Motivation Solution Changes since the last version Next step. Motivation.
E N D
FEC framework Configuration Signaling draft-ietf-fecframe-config-signaling-02.txt IETF 76 Rajiv Asati draft-ietf-fecframe-config-signaling-02
Agenda • Motivation • Solution • Changes since the last version • Next step draft-ietf-fecframe-config-signaling-02
Motivation • Per FEC Framework, the FEC encoder and FEC decoder must have the common FEC Framework Configuration Information (FFCI) • Identification of Source Flow(s) • Identification of the repair flow(s) • Identification of FEC Scheme • Length of Source FEC payload ID • FEC Scheme Specific Information (FSSI) draft-ietf-fecframe-config-signaling-02
Solution • Dynamic signaling of the FEC Framework Configuration Informationbetween FECencoder (or sender) and decoders (or receivers). • Two signaling methods(in section 4)- • Session Announcement Protocol for Multicasting • Individual application protocol for Unicasting; No dedicated protocol. FEC_Sender2---------| |--------FEC_Receiver2 | | FEC_Sender1-----IP/MPLS network |-----------FEC_Receiver11 |-----------FEC_Receiver12 |-----------FEC_Receiver13 draft-ietf-fecframe-config-signaling-02
Solution • More details in additional slides.. draft-ietf-fecframe-config-signaling-02
Changes since the last version • Reviewed in detail during WGLC • Thanks to Ali Begen (16 comments) and Vincent Roca* (24 comments). They helped to improve the document greatly. • Fixed Terminology, and few Editorial stuff.. • Updated • Destination multicast IP address for IPv4 admin scope • hold timer to be 5x announcement interval • Added the request for an RSTP option-tag for 'FEC protection required’ (section 4.2.2) • Removed DSM-CC reference * Acknowledgement section needs to be updated draft-ietf-fecframe-config-signaling-02
Changes since the last versionOne last outstanding Q • Should the “time-interval” (section 4.1.1) be a user defined value or derived from a complex formula or both? • Current prescription: • User defined value: MUST (deterministic value) • Complex formula: MAY (non-deterministic value) draft-ietf-fecframe-config-signaling-02
Next Steps • WGLC already ended, so proceed towards IESG review. • More WG feedback is welcome draft-ietf-fecframe-config-signaling-02
Additional Slides Taken from -00 slides presented at IETF 72 draft-ietf-fecframe-config-signaling-02
Solution Details • The solution can be utilized by any FEC scheme and/or any Content Delivery Protocol (CDP). Hence, it is independent of the • FEC scheme, • Content Delivery Protocol • Encoding format of the configuration information (for multicast). draft-ietf-fecframe-config-signaling-02.txt
Solution DetailEncoding Format • Each instance of the FEC Framework must use a single encoding format to describe all of the configuration information (FFCI) associated with that instance. • Whatever encoding format is selected for a particular FEC framework instance, it must be signaled to the receiver. • Enables correct parsing by the recipient. draft-ietf-fecframe-config-signaling-02.txt
Solution DetailMulticasting of Config Information • Session Announcement Protocol (SAP) [RFC2974] is used to signal the FEC Framework Configuration Information (FFCI). • FEC sender acts as the SAP announcer • FEC receiver acts as the SAP listener • SAP messages are sent UDP over IP to a well known UDP port (9875) and at least one well known multicast group IP address. • IPv4= 239.16.33.254 (admin scope) or 224.2.127.254 (global scope) • IPv6= FF0?:0:0:0:0:0:2:7FFE • IP TTL and DSCP values of SAP messages may be set by the sender. • FEC sender doesn’t need to maintain any state per receiver. draft-ietf-fecframe-config-signaling-02.txt
Multicasting of Config InformationSender Procedure • FEC sender periodically signals the FFCI for each FEC Framework instance ‘available’ at the sender • FFCI is placed in the SAP payload of Announcement message 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | V=1 |A|R|T|E|C| auth len | msg id hash | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | : originating source (32 or 128 bits) : : : +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | optional authentication data | : .... : *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* | optional payload type | + +-+- - - - - - - - - -+ | |0| | + - - - - - - - - - - - - - - - - - - - - +-+ | | | : payload : | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ • The periodic interval* is 1-200sec (range) with default=60sec. • Session can be deleted by SAP delete message or the purge-time expiry. Updated • Purge time = 3 x announcement interval. draft-ietf-fecframe-config-signaling-02.txt * See note.
Multicasting of Config InformationReceiver Procedure • FEC receiver obtains the FFCI for each FEC Framework Instance from the payload of the received SAP announcements. • Creates an entry in the local SAP database, • Passes the FFCI to the ‘FEC Framework’ module. • When a matching announcement is received the next time, the FEC receiver should reset the timer of the corresponding entry, to avoid it being purged. • The purge time = 3 x announcement interval. draft-ietf-fecframe-config-signaling-02.txt
Solution DetailUnicasting of Config Information • No dedicated protocol proposed for unicasting. • The proposal is to enable the individual application protocol such as SIP, RTSP etc. to convey the desire to use FEC and exchange FFCI. • The offer/answer signaling, described in [RFC3264], is commonly utilized by many application protocols. • Either FEC sender or FEC receiver conveys the desire to use FEC, and once agreed, they can exchange the FFCI. • The draft includes text to describe SIP, RTSP etc. • Anything else? draft-ietf-fecframe-config-signaling-02.txt