1. March 2015 IETF 92 Authors: Tirumaleswar Reddy, Dan Wing, Pål-Erik Martinsen and Varun Singh Presenter : Varun Singh draft-reddy-tram-stun-path-data-01 1 Discovery of path characteristics using STUN draft-reddy-tram-stun-path-data-01

2. Problem to solve How to prioritize ICE candidate pairs based on path characteristics ? 2 draft-reddy-tram-stun-path-data-01

3. Issues with STUN STUN can be used to discover the path characteristics but STUN responses from re- transmitted requests are indistinguishable. 3 draft-reddy-tram-stun-path-data-01

4. Proposal Extend STUN to distinguish STUN responses to retransmitted requests. Measure path characteristics like RTT and packet loss in each direction between endpoints. 4 draft-reddy-tram-stun-path-data-01

5. PATH-CHARACTERISTIC Attribute in request 5 ReTransCnt Number of times request re-transmitted with the same Transaction ID draft-reddy-tram-stun-path-data-01

6. PATH-CHARACTERISTIC Attribute in response 6 ReqTransCnt 0 0 0 0 0 0 0 0 ReTransCnt RespTransCnt Number of times request is received from the client with the same transaction ID Number of times responses sent to the client for the same transaction ID Copied from request draft-reddy-tram-stun-path-data-01

7. Other benefits Determine the priority amongst relayed candidates when multiple TURN servers are discovered. Interfaces for the MPRTP sub-flows can be chosen according to the path characteristics discovered using STUN. 7 draft-reddy-tram-stun-path-data-01

8. Ready for adoption? draft-reddy-tram-stun-path-data-01 8 Discovery of path characteristics using STUN