draft-ietf-fecframe-config-signaling-02 1 fec framework configuration signaling...

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draft-ietf-fecframe-config-signaling-02

FEC framework Configuration Signaling

draft-ietf-fecframe-config-signaling-02.txt

IETF 76

Rajiv Asati

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Agenda

• Motivation• Solution• Changes since the last version • Next step

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Motivation• Per FEC Framework, the FEC encoder and FEC

decoder must have the common FEC Framework Configuration Information (FFCI)

1. Identification of Source Flow(s) 2. Identification of the repair flow(s) 3. Identification of FEC Scheme 4. Length of Source FEC payload ID 5. FEC Scheme Specific Information (FSSI)

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Solution • Dynamic signaling of the FEC Framework Configuration

Information between FEC encoder (or sender) and decoders (or receivers).

• Two signaling methods (in section 4)- 1. Session Announcement Protocol for Multicasting 2. Individual application protocol for Unicasting; No dedicated

protocol.

FEC_Sender2---------| |--------FEC_Receiver2 | |FEC_Sender1-----IP/MPLS network |-----------FEC_Receiver11 |-----------FEC_Receiver12 |-----------FEC_Receiver13

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Solution

• More details in additional slides..


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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

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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)


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Next Steps

• WGLC already ended, so proceed towards IESG review.

• More WG feedback is welcome

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Additional Slides

Taken from -00 slides presented at IETF 72


10draft-ietf-fecframe-config-signaling-02.txt

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).


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.


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.


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

* See note.

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.


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.


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?

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