Review: Internet Indirection Infrastructure

Review: Internet Indirection Infrastructure

Reviewer: Di Niu

This paper proposes Internet Indirection Infrastructure (i3) to ease
the deployment of such service abstractions as multicast, anycast,
and mobility. All attempts to implement these abstractions had relied
on a layer of indirection that decouples the sending hosts from the
receiving hosts; for example, senders send to a group address, and
the IP layer of the network is responsible for delivering the packet
to the appropriate locations. However, these abstractions have proven
difficult to implement scalably at the IP layer. Moverover, deploying
additional functionality at the IP layer requires a level of
community-wide consensus and commitment that is hard to achieve.

Faced with such problems, the paper proposes i3 that offers a
powerful and flexible rendezvous-based communication abstraction. It
decouples the act of sending from the act of receiving. Unlike IP
multicast, the i3 equivalent of a join is inserting a trigger, which
allows receivers to control the routing of the packet. This way, the
infrastructure can give responsibility for efficient tree
construction to the end-hosts. Specifically, packets in i3 are pairs
(id, data) where id is an m-bit identifier and data consists of a
payload. Receivers use triggers to indicate their interest in
packets. For example, a typical communication between two nodes is
performed in the following way: the receiver inserts the trigger (id,
R) into the network. When a packet is sent to identifier id, the
trigger causes it to be forwarded via IP to R. One of the main
challenges in implementing i3 is to efficiently match the identifiers
in the packets to those in triggers. This is done by mapping each
identifier to a unique i3 node.

This paper is interesting in that it proposes a new abstraction that
unifies the solutions for mobility, anycast and multicast in the
Internet. The originality here is that a rendezvous-based
communication abstraction is employed to decouple the behaviors of
the receivers and senders. The paper also provides solid experimental
studies through building an overlay network based on the Chord lookup
system.
Received on Thu Nov 23 2006 - 00:27:20 EST