7/28/2019 Umesh Stn Pre

1/19

Umesh Piparava

Internet indirection

Infrastructure

Umesh Piparava

February 27, 2013

http://goforward/http://find/http://goback/

7/28/2019 Umesh Stn Pre

2/19

Umesh PiparavaIntroduction

Todays Internet is built around a point-to-pointcommunication abstraction

One sender,One receiver Fixed location,which is well-known Host A sends packet p to host B,identified by IP

Internet has Scalability Efficiency

But...many applications would benifit from a moregeneral communication abstraction:

Multicast Anycast Mobility

.

http://find/http://goback/

7/28/2019 Umesh Stn Pre

3/19

Umesh PiparavaIntroduction(2)

Why not appropriate?

sending host no longer knows identity of receiving host The location of the receiving host need not be fixed

Fundamental mismatch between original point-to-pointabstraction and multicast,anycast , mobility.

http://find/

7/28/2019 Umesh Stn Pre

4/19

Umesh PiparavaMotivation

Need an alternative communication abstraction layer of indirection that decouples the sending hosts

from the receiving hosts

Existent solutions: Network layer: IP multicast,mobile IP

Difficult to implement scalability Application layer

Disjoint functionality

Indirection More general abstraction Decouples the sending hosts from the receiving host Send packet p to a rendezvous IP layer will send p to the receiver

http://find/http://goback/

7/28/2019 Umesh Stn Pre

5/19

Umesh Piparavai3 overview

An additional overlay network on top of IP

Best-effort service

general purpose and flexible rendezvous-basedcommunication abstraction.

http://find/

7/28/2019 Umesh Stn Pre

6/19

Umesh Piparavai3-service model

Rendezvous-based communication

Receiver R maintains the Trigger(ID,R) ID-Identifies the flow of packets R Address of the Receiver

Best-effort service model

http://find/

7/28/2019 Umesh Stn Pre

7/19

Umesh Piparavai3

A packet (ID,data) will inserted into the overlaynetwrok and then forwarded by the i3 infrastructure to

the corresponding node identified by trigger(ID,R) From there the packet will be forwarded via IP to the

receiver

http://find/

7/28/2019 Umesh Stn Pre

8/19

Umesh PiparavaMobility

Host only needs to update the trigger ID represents the logical rendezvous between the

senders packets and the receivers trigger decouples the sender from the receiver

i3 is an overlay network consists of a set of servers that store triggers and

forward packets using IP between i3 nodes and endhosts

each identifier is mapped to a unique i3 node When a trigger (ID,R)is inserted it is stored on the i3

node responsible for this ID when a packet is inserted into the overlay network,it is

routed by i3 to the node responsible for ID There it is matched against any triggers for that ID

and forwarded(using IP)to all hosts interested inpackets sent to that identifier

http://find/

7/28/2019 Umesh Stn Pre

9/19

Umesh PiparavaMobility

Host only needs to update the trigger

http://find/

7/28/2019 Umesh Stn Pre

10/19

Umesh PiparavaMulticast

Any packet that matches ID will be forwarded to all themembers of the group

http://find/http://goback/

7/28/2019 Umesh Stn Pre

11/19

Umesh PiparavaAnycast

Longest prefix matching

Packet is delivered to a member of group whose triggeridentifier best matches the packet identifier Triggers identifiers share a common prefix p

http://find/

7/28/2019 Umesh Stn Pre

12/19

Umesh PiparavaService Composition

Stack of identifiers Identifier ID is replaced with a stack of identifiers

Packet p=(idstack,data) Trigger t=(id,idstack)

greater flexibility Packet p is always forwarded based on the first identifier

in the stack until it reaches the server storing thematching triggers for p

Matching server pops the head of the stack & forwards

on the packet

http://find/

7/28/2019 Umesh Stn Pre

13/19

Umesh PiparavaService Composition(2)

Some applications may require third parties to process

data before it reaches the destination Receiver is not aware of data transformations

http://find/http://goback/

7/28/2019 Umesh Stn Pre

14/19

Umesh PiparavaHeterogeneous multicast

sender is not aware of the data transformations

http://find/http://goback/

7/28/2019 Umesh Stn Pre

15/19

Umesh PiparavaLarge Scale Multicast

The multicast abstraction presented earlier does notscale to large groups

Identical identifiers are stored on the same i3 servers

Use stack identifiers to create a hierarchy

http://find/

7/28/2019 Umesh Stn Pre

16/19

Umesh PiparavaImplemetation

i3 is implemeted on top of chord circular identifier space Each server has a unique identifier

Each trigger(ID,R) is stored on the node(server)responsible for ID

Chord routing is responsible for finding the bestmatching trigger for packet(ID,data)

O(log n)hops to locate the responsible server for

an arbitary identifier (n=number of servers)

http://find/

7/28/2019 Umesh Stn Pre

17/19

Umesh Piparavaconclusion

Main idea :indirection

More general abstraction in one overlay Multicast Antcast Mobiity Service Composition

Based on Chord

http://goforward/http://find/http://goback/

7/28/2019 Umesh Stn Pre

18/19

Umesh Piparava

ANY QUERIES ???

http://find/

7/28/2019 Umesh Stn Pre

19/19

Umesh Piparava

Thank YOU ...

http://find/