1. ECE 544 Project3
Dheeraj Medikonda
Ravi Chandra Godavarthi 1

2. 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

3. 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

4. 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

5. 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

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

7. 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

8. Appendix: Network Architecture
Scenario 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

9. Appendix: Network Architecture
Scenario 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

10. Thank You!