1. GROBJ Problem Statement – GROBJ BoF – IETF76 1 GROBJ BoF: Problem Statement Dan Wing, dwing@cisco.com v0.3, revised: 2-Nov-2009

2. GROBJ Problem Statement – GROBJ BoF – IETF76 2 Application Connection Problem Things are getting more complicated 1.IPv6/IPv4 2.Transport protocol 3.Path selection 4.Optimal path selection 5.NATs

3. GROBJ Problem Statement – GROBJ BoF – IETF76 3 Three Party Case “Alice”, “Bob”, “Carol” Slightly more complex GRO’s model ◄ Solving this case solves the 2 party case XMPP alicebob XMPP GRO carol 1 2 3 GRO

4. GROBJ Problem Statement – GROBJ BoF – IETF76 4 Two Party Case “Alice, Bob” Simple to understand demonstrates we have a problem Discussed in this presentation XMPP alicebob voice, gaming

5. GROBJ Problem Statement – GROBJ BoF – IETF76 5 Setup: Alice and Bob XMPP alice Alice and Bob want to communicate directly –Interactive video –File sharing –Gaming They are using a rendezvous service (XMPP) bob voice, gaming

6. GROBJ Problem Statement – GROBJ BoF – IETF76 6 Problem 1: IP Family XMPP alice Alice’s network supports IPv6 Bob’s network supports IPv4 That’s a problem! bob IPv4? IPv6?

7. GROBJ Problem Statement – GROBJ BoF – IETF76 7 Problem 2: transport protocol XMPP alice Alice’s wants to use fancy new transport (e.g., MP-TCP, SCTP) Bob’s network only handles TCP That’s a problem! bob MP-TCP? SCTP?

8. GROBJ Problem Statement – GROBJ BoF – IETF76 8 Problem 3: path selection XMPP alice Alice and Bob are on several networks Which paths work? That’s a problem! bob ? ?

9. GROBJ Problem Statement – GROBJ BoF – IETF76 9 Problem 4: optimal path selection XMPP alice Alice and Bob are on several networks Which paths work best? –cost –performance That’s a problem! bob ? ?

10. GROBJ Problem Statement – GROBJ BoF – IETF76 10 Problem 5: NATs XMPP alice Alice is behind a NAT –NAT64 or NAT44 Alice doesn’t have global IPv4 address scope. That’s a problem! bob ? XMPP

11. GROBJ Problem Statement – GROBJ BoF – IETF76 11 Problem Summary Solving the problems is hard. Most applications don’t bother –“My users aren’t multihomed” – but WiFi, wired Ethernet, and 3G/4G changes that –“My application will use UPnP IGD” –IPv6 transition: native IPv6, NAT64, NAT44 (DS-Lite) All applications should make the same decisions –Games, SIP, XMPP

12. GROBJ Problem Statement – GROBJ BoF – IETF76 12 Proposed Solution Applications send a Generic Referral Object (GRO) –Contains everything necessary to communicate directly XMPP alicebob XMPP GRO carol GRO 1 2 3

13. GROBJ Problem Statement – GROBJ BoF – IETF76 13 GRO and ICE ICE also allows choosing UDP/TCP/IPv6/IPv4 But, ICE is specific to SDP and SIP’s Offer/Answer model ICE has been used by other protocols: –RTSPv2, XMPP GROBJ is more general –remove the intertwining of an application –So that GROBJ can be useful to other applications ICE: draft-ietf-mmusic-ice RTSPv2 with ICE: draft-ietf-mmusic-rtsp-nat XMPP with ICE: http://xmpp.org/extensions/xep-0176.html

14. GROBJ Problem Statement – GROBJ BoF – IETF76 14 GROBJ Purpose Provide guidance to applications to better use host network connectivity Today share one IPv4 address, and maybe a port Tomorrow with GRO Share all available IPv4 & IPv6 addresses and ports, and transport protocols Indicate preferences Applications