1. draft-gu-ppsp-protocol-00 PPSP Session IETF 77, Anaheim March 22, 2010

2. 2 PPSP Tracker Protocol Basic proposal for a tracker protocol to get things rolling, start questions/discussion etc. Basic properties: –Supports JOIN/LEAVE, PUT/GET, keep alive messages and status/statistics messages –Binary encoding (current proposal…open question)

3. 3 Missing Things… Things we know or may be needed but haven’t had time to add: –NAT Traversal (some things to support for peers in place) –Peer promotion (if distributed) Things that are incomplete –Fragmentation –How leaving is handled (peer removes or tracker removes?)

4. 4 Encoding Issues Current proposal uses binary encoding –Light weight, easy to parse –Of course not human readable –Text encoding is an open issue HTTP with payload –Is this an appropriate reuse? –Many admins like to treat P2P traffic differently than web traffic

5. 5 NAT Traversal Issues We’ve added fields to let peers indicate if they can provide STUN/TURN services, etc. Currently don’t support NAT traversal to Tracker –If we allow distributed tracker, need this, need to talk about promotion of peers We know we have trackers, do we use them to help peers with NAT traversal? (broader open issue: how “coupled” are peer and tracker protocols?) GET responses currently provide the PeerID, not IP (but this is open for discussion…) –Use IP addresses in JOIN. Needed? –Motivated by NATs, but broader issue…

6. 6 Leaving Issues When leaving, where is the responsibility to remove information? –Option 1 : Peer sends leave (tracker removes) –Option 2 : Peer sends removes, then leaves (peer removes) –In a centralized tracker, 1 seems far more efficient. Problems with a fully distributed tracker? What information is stored by tracker is still open…

7. 7 Specifying Preferences in GET We have a basic mechanism for specifying preferences for a peer –Specify a long-lived peer, a secure peer, specifications about NAT… –Do we have the right set of possibilities? –Do we need this capability? –Is this enforceable?

8. 8 Missing Features? Comment that draft-li-ppsp-p2p-cdn-00 has “pre-fetch” for fast movie changing –How do you decide what to pre-fetch?

9. 9 Looking for Feedback Looking for list discussion on: –The open issues we’ve presented here and in the draft –Overall protocol design –Right features? –Once we know more…what is relationship with peer protocol?