ECE 544 Project3 Amith V.S Pavan Kulkarni Suneet Dixit

Assumptions and Address Scheme Assumptions Routers do not fail in the life time of the Network. Router to Router Links do not fail in the life time of the Network. IPs of all the Routers are preassigned. Routers assign IPs to all the hosts in the Network. Naming scheme and eventual address scheme Edge routers are assigned IPs in the form X.X.n.0 where n ranges from End hosts are assigned IPs in the form X.X.n.h where n is the subnet number as assigned above and h ranges from (since no. of hosts connected to network N < 255). Content files are identified by their content ID ranging from (since no. of contents in the network K < 255).

Bootstrapping and Discovery Modified Link State Algorithm - MLSF Extends the functionality of Link state algorithm to support the functionality of Content Provider Network. Initially each of the edge router sends the contents that are available in their subnet along with the distance vector to their adjacent routers. After the convergence of the network each of the router will have a table as shown below: Time Stamp DestinationCostNext HopContents

Bootstrapping and Discovery Discovery Routers discover other routers with Hello Packets as shown Below : Edge routers discover their hosts and contents present in them with Hello Packets as shown below : Router Source IPContent Indicator Array 32 Bits256 Bits Host IP addressContent ID array 32 bitsVariable Length

Baseline Algorithm Content routing algorithm Once the Modified Distance Vector Algorithm – Routing Table is established in each of the Router, the network is now ready to respond to the get(ContentID) request. How to route a content-request packet? For each of the request issued by a host, the packets are generated in following format: The edge router receives this packet and converts it into Router-Router request packet as shown below: Host Source IPFlagContent ID 32 Bits8 bits Host Source IPDestination Router IP FlagContent ID 32 Bits 8 Bits

Baseline Algorithm How to route a content-request packet(cont..)? This packets traverses the network through the shortest path and reaches the edge router which is connected to the host which has the content. Each edge Router has a table mapping the Hosts IP address to the contents the host has. Referring to this table the packet is forwarded to the appropriate host. The host extracts the packet and gets the content ID requested and generates the response packet as shown Host Destination IP FlagContent IDContent 32 Bits8 Bits Upto 1466 Bytes

Baseline Algorithm How the content is actually delivered? While the request packet traverses through the network it updates the bread crumbs table as shown below present in each router : The response packet refers the bread crumbs table to get the next hop. How network is updated when a host has a new content? When a host has a new content, a new content packet is generated as shown and forwarded to the edge router: Destination IP addressNext Hop IP address 32 Bits Host Source IP FlagContent IDTime Stamp 32 bits8 bits 32 Bits

Baseline Algorithm How network is updated when a host has a new content(cont..)? The edge router gets this packet replaces the host IP address with its own IP address and broadcasts the packet to all the connecting Routers. This is continued as Spanning tree algorithm with Time Stamp as the update parameter. Thus all the router's MDVA table is updated. How network is updated when a host deletes a content(cont..)? The same procedure is followed as above with the flag set to delete content.

Data Transfer and Reliability Message Forward Host – Router is Unicast Hello Packets and Update Packets between Routers is Multicast ARQ Scheme Hop-by-hop acknowledgement scheme is being used at every router

Advantages Algorithm: A modified version of the Distance Vector Table is being used which efficiently calculates the shortest path to the host which has the required contents Scalability: The method employed can be extended by using the unused bits of the IP address making the system scalable Latency: The method employs bread crumbs to send data back to the requesting host. In this way a low latency is maintained

Disadvantages As Distance Vector Algorithm is a decentralized routing algorithm, it takes time to converge the table Hop-by-hop acknowledgement scheme may introduce latency

Appendix: Network Architecture Example scenarios for analysis purposes: H1 H2 H3 C1 C2 C3 R1R2R3R4 R5 Scenario get (content_C3)

Appendix: Network Architecture H1H1 H2H2 H3H3 C1C1 C1C1 C2C2 C2C2 C2C2 C2C2 C3C3 C3C3 C3C3 C3C3 R1R2R3R4 R5 Scenario get (content_C2)

Appendix: Network Architecture H1 C3 Scenario get (content_C1) H2H3 H4 C1 C2 C1