ECE 544 Project3 Dheeraj Medikonda Ravi Chandra Godavarthi 1

Assumptions and Address Scheme End hosts can only connect to routers Same content available at multiple end nodes Selecting best node is based on No. of Hops. Lossy links of probability p Naming scheme and eventual address scheme Router/ End hosts- IP address ( Interfaces are named 0,1,..etc) Content – Addressed with ID [0-255] 2

Bootstrapping and Discovery Algorithm Routers and end hosts boot up Routers send LSP packets to form the routing table (Link State Routing) End Hosts send Hello packet to their router and vice verse Discovery Routers discover other routers using their LSP packets Hosts discover their router and vice verse using hello packets 3

Bootstrapping and Discovery Packet Format Router-Router Discovery [ Type | Packet Length | Options | Source IP address| Dest IP address] Router- End node Discovery [ Type | Packet Length | Options | Source network address | Routers Network address ] Type= 4 bits , Length = 20bits ,TTL/Options = 8 Bits Source IP = 32 Bits Dest IP = 32 bits 4

Baseline Algorithm Content routing algorithm Each host advertises its contents to its attached router via a content broad cast packet using LSP type broad cast A content-discovery packet is routed similar to a LSP packet using additional content routing information The decision of choosing the best host is done based on content routing table – no. of hops Packet Format [ Type | Packet Length | Options | Content Providers/requesters address | Content ID ] 5

Data Transfer and Reliability Message Forward Request - Unicast Reply – Multicast Packet Format of DATA, ACK |Type of packet - 4 | Length - 20 | Type of request -4 | | Content ID - 20 | Options - 16 | | Multicast Address -32 | | Content -1500B | ARQ Scheme Hop-by-hop Stop-and-wait 6

Advantages and Disadvantages Multicast helps reduce congestion A central content availability database and content routing index is not required Scalability is poor due to Flat content addressing

Appendix: Network Architecture Scenario 1: @host_H2: get (content_C3) H2 C1 C2 R5 C3 H1 R1 R2 R3 R4 H3 After the Content discovery packet is sent through out the network routers, we now have a content routing table at R5 → R2 → R3 → R4 → H3 telling us the content C3 is at H3. Eg: at R2 we have [ C3 | 3 Hops | R3 ] where each field is [Content ID | no of hops | next hop ] 8

Appendix: Network Architecture Scenario 2: @host_H1: get (content_C2) H1 H2 H3 C1 C2 C3 R1 R2 R3 R4 R5 We choose H2 over H3 Content Routing table at R2 Content Routing table at R1 Content ID No of Hops Next Hop C2 2 R5 3 R3 Content ID No of Hops Next Hop C2 3 R2 4

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