CS 268: Lecture 25 Indirection

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CS 268 Lecture 25Indirection
Ion Stoica Computer Science Division Department
of Electrical Engineering and Computer
Sciences University of California,
Berkeley Berkeley, CA 94720-1776
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Indirection is Everywhere!
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Why Indirection?

• Decouple sender behavior from receiver behavior
• Receiver movements and address changes
  transparent to sender
• Changes in the number of receivers, transparent
  to sender

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Discussion

• Control
• Indirection point ? point where control is
  transferred from sender to receiver
• Translation/forwarding entry usually controlled
  by receiver
• Resolution
• Early binding (e.g., DNS, SIP, HIP)
• Late binding (e.g., Mobile IP, NAT,IP multicast,
  IP anycast)

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End-host Empowerment

• Both the sender and receiver should be able to
  explicitly control the service-path
• Note multiple indirection points possible

Internet
Application Layer Service (ALS) 1
ALS 2
ALS 3
ALS 4
Receiver
Indirection point (tussle boundary)
Sender
sender control
receiver control
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Realization i3 vs DOA
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Discussion DOA vs. HIP vs. i3 (1/2)

• Naming Flat ID space
• DOA two levels of IDs
• EID end-host IDs
• SID service IDs
• Resolution (SID?EID) (EID?IPaddr)
• HIP
• HIT host identity tag
• Resolution (HIT?IPaddr)
• i3
• ID identifies anything
• Resolution (ID?IPaddrPort), where
  IPaddrPort represents de-multiplexer

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Discussion DOA vs. HIP vs. i3 (2/2)

• Resolution
• HIP and DOA early binding
• i3 late binding
• Lookup Forwarding
• i3 combines lookup forwarding infrastructure
• Degenerates to a lookup infrastructure when
  shortcuts are used
• DOA forwarding state at ALSes