ECE 544 Project3Group 9

Brien RangeSidhika Varshney

Sanhitha Rao Puskuru

Assumptions and Address Scheme

Assumptions End hosts can only connect to routers and only

one router Same content available at multiple end nodes When data is requested, it is copied, not deleted

from the content provider.

Bootstrapping and Discovery Algorithm

Routers and end hosts boot up – Routers and end hosts send a “Hello” packet on all ports and waits for a response. End host keep track of ports where it received response, routers

Discovery N - Routers discover other routers via N discovery packets

with updated routing tables, every 30 seconds, “hello” packets every 30 seconds

Router uses STP

Baseline Algorithm Content routing algorithm

How are contents advertised? – Content Requesters send multicast request, content owners reply Broadcasts are only sent over ports that are part of the minimum spanning tree to end hosts

How to route a content-request packet? - multicast How to choose the ‘best’, among multiple hosts having the same content? –

second request is sent after response of first request, first router choosing best path

How is the content actually delivered? One to Many multicast request Many to one unicast response One to One request to router with eligible content hosts One to one request from router to closest content host Direct unicast transfer from host to host

Data Transfer and Reliability Message Forward

Request(contentname) – Multicast Get(contentname,requester,*contentsources) – Unicast, Sent to linked

Router <source><destination1><flags><data-destination2,destination3,…> Get(contentname,requester,contentsource) – Sent from router to closest

source Response(requester,closestcontentsource,contentdata) – Sent from

content owner to source

ARQ Scheme End-to-end – the routers will not require flow state Request - Stop-and-wait because it is a multicast request Get – Stop-and-wait because there is no variable data content/size Response - sliding window because actual data is being transferred

Advantages and Disadvantages Scalability? – The design is not scalable, because of the

N <= 255 hosts. However, there is less overhead, because we are not implementing a layer 3 protocol

Latency Example 1 is 16 Hops Example 2 is 16 Hops Example 3 is 32 Hops

Not reliant on availability of single content server or host database Resilient to link failure

Packet Formats

Example Scenarios Use the example scenarios (from the

Appendix) to highlight the key aspects of your proposal

Appendix: Network Architecture

Refer to the following example scenarios for analysis purposes:

H1

H2

H3

C1 C2C3

R1 R2 R3 R4

R5

Scenario 1: @host_H2: get (content_C3)

H1

H2

C1 C2C3R5

H1

H2

C1 C2C3R5

  Request -Broadcasted by R2 to R3 and R1  Response from H3  Get() with H2’s address as the destination address forwarded to R5 and R5 will

forward it without any update  Transfer of the content

Appendix: Network Architecture

H1

H2

H3

C1

C2

C2

C3

C3

R1 R2 R3 R4

R5

Scenario 2: @host_H1: get (content_C2)

H1

H2

H3

C1

C2

C2

C3

C3

R1 R2 R3 R4

R5

H1

H2

H3

C1

C2

C2

C3

C3

R1 R2 R3 R4

R5

  Request – From H1 is broadcasted by R2 to R5 and R3  Responses from H3 and H2  Get() from H1 with H2’s address as the destination address and other Content address also is forwarded to R1 and R1

will update the destination address with the closest Host and delete the other content addresses i.e. address of H2  Transfer of the content

Appendix: Network Architecture

H1

C3

Scenario 3: @host_H1: get (content_C1)

H2 H3 H4C1 C1

C2C1

  Request – From H1 is broadcasted by R13 to the respective routers

  Responses from H2, H3 and H4

  Get() from H1 with H2’s address as the destination address and other Content addresses also is forwarded to R13 and R13 will update the destination address randomly from H2 or H3 and delete the other content addresses.

  Transfer of the content

Source-Destination

Distance Between them

H1- H2 4

H1-H3 4

H1-H4 5