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GROBJ BoF: Problem Statement. Dan Wing, [email protected]. v0.3, revised: 2-Nov-2009. Application Connection Problem. Things are getting more complicated IPv6/IPv4 Transport protocol Path selection Optimal path selection NATs. “Alice”, “Bob”, “Carol” Slightly more complex GRO’s model ◄ - PowerPoint PPT Presentation
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GROBJ Problem Statement – GROBJ BoF – IETF76 1
GROBJ BoF:Problem Statement
Dan Wing, [email protected]
v0.3, revised: 2-Nov-2009
GROBJ Problem Statement – GROBJ BoF – IETF76 2
Application Connection Problem
• Things are getting more complicated1. IPv6/IPv4
2. Transport protocol
3. Path selection
4. Optimal path selection
5. NATs
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 XMPP
alice bob
XMPP
GRO
carol
1 2
3
GRO
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 XMPP
alice bob
voice, gaming
GROBJ Problem Statement – GROBJ BoF – IETF76 5
Setup: Alice and Bob
XMPP XMPP
alice
• Alice and Bob want to communicate directly
– Interactive video
– File sharing
– Gaming
• They are using a rendezvous service (XMPP)
bob
voice, gaming
GROBJ Problem Statement – GROBJ BoF – IETF76 6
Problem 1: IP Family
XMPP XMPP
alice
• Alice’s network supports IPv6
• Bob’s network supports IPv4
• That’s a problem!
bob
IPv4? IPv6?
GROBJ Problem Statement – GROBJ BoF – IETF76 7
Problem 2: transport protocol
XMPP 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?
GROBJ Problem Statement – GROBJ BoF – IETF76 8
Problem 3: path selection
XMPP XMPP
alice
• Alice and Bob are on several networks
• Which paths work?
• That’s a problem!
bob
?
?
GROBJ Problem Statement – GROBJ BoF – IETF76 9
Problem 4: optimal path selection
XMPP XMPP
alice
• Alice and Bob are on several networks
• Which paths work best?
– cost
– performance
• That’s a problem!bob
?
?
GROBJ Problem Statement – GROBJ BoF – IETF76 10
Problem 5: NATs
XMPP XMPP
alice
• Alice is behind a NAT
– NAT64 or NAT44
• Alice doesn’t have global IPv4 address scope.
• That’s a problem!bob
?
XMPP
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
GROBJ Problem Statement – GROBJ BoF – IETF76 12
Proposed Solution
• Applications send a Generic Referral Object (GRO)– Contains everything
necessary to communicate directly
XMPP XMPP
alice bob
XMPP
GRO
carol
GRO
1 2
3
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-iceRTSPv2 with ICE: draft-ietf-mmusic-rtsp-nat
XMPP with ICE: http://xmpp.org/extensions/xep-0176.html
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