1. ECE 544 Project3
Team member:
BIAO LI, BO QU, XIAO ZHANG 1 1

2. Assumptions and Address Scheme
End hosts can only connect to one router
Same content available at multiple end nodes
the path cost between adjacent router is 1.
Host and content can move at any time
Naming scheme and eventual address scheme
Router ID (statically assigned, range 0~255)
End hosts ID (statically assigned, range 0~255)
Content ID (statically assigned, range 0~255) 2 2

3. Our Goal
Keep it simple 3 3

4. We Don't care How to assign a Address to a Host
How to assign a Address to a Router
How to generate a ID for a Content 4 4

5. How to build a forwarding table
We Do care
How to forward a packet
How to build a forwarding table 5 5

6. Forwarding Table (@ R1) ID (Content or Host) Interface C1 1 H1 C3 2 C2

7. Scenario 1: @host_H1: get (content_C2)
Forwarding
ID (Content or Host)
Interface C1 1 H1 C2 2 C3 H2
Forwarding
ID (Content or Host)
Interface C1 1 H1 C3 3 C2 2 H2 H3
Packet
Forwarding
ID (Content or Host)
Interface C1 2 H1 C3 C2 1 H2 H3
Src
Dest H1 C2
File Packet
Src
Dest C2 H2 C2 H2 C2 H1 1 C1 R5 2 C3 H1 2 1 2 1 3 R1 R2 R3 R4 H3 H1 C2 7 7

8. Then … ...
How to build
a Forwarding table? 8 8

9. Resource Table maintained at each router
contains the location information regarding host and content
when ID is content, owner ID is a list of hosts.
when ID is host, owner ID is its directly connected router.
Resource R1
ID (Content or Host)
Owner ID C1 H1
self H2 R5 C2 H3 C3 R4 H2 C1 C2 R5 C3 H1 2 1 2 1 3 R1 R2 R3 R4 H3

10. Routing Table
need not to be computed every time unless something changed in link-state table
Destination
Next Hop
Cost R2 1 R3 2 R4 3 R5 H2 C1 C2 R5 C3 H1 2 1 2 1 3 R1 R2 R3 R4 H3

11. Then … ...
How to build
a Routing table? 11 11

12. Routing Table (shortest path)
need not to be computed every time unless something changed in link-state table (for
Destination
Next Hop
Cost R1
port 1 1 R3
port 3 R4 2 R5
port 2 H2 R5 2 2 1 3 R1 R2 R3 R4 12

13. Link-State Table ( the same at each router )
remain unchanged after routers boot up unless some new router is added or failure of some router is detected.
Connected? R1 R2 R3 R4 R5 - T F R5 2 2 1 3 R1 R2 R3 R4 13

14. Router Bootstrapping and Discovery
Each Router find its directly connected neighbors
Exchange the information of neighbors
Each router would have the same view of the global topology
Each router can computes its shortest path to reach other router 14 14

15. Neighbor Neighbor of R2 Router ID Interface R5 2 R3 3 R1 1 R5 2 2 1 315

16. Neighbor @ R5 Router Neighbor R2 R5 R3 R1 R4 Router Neighbor R2 R5 R3
RID
Port R2 2 C1 R5 C2 C3 1 2 H1 1 1 2 1 2 2 3 R1 R2 R3 R4 H3
RID
Port R2 2
RID
Port R5 2 R3 3 R1 1
RID
Port R2 1 R4 2
RID
Port R3 1

17. Loop-free
Note that we includes the complete paths as a enumerated list of routers when flooding the message. As long as a router finds itself included in the path, it would ignore this message to avoid path loop.
When R1 receives the message sent by R2 that
<R1 is neighbor PATH: R1- R2>, R1 no longer relays the message. R5 2 2 1 3 R1 R2 R3 R4 17

18. Then … ...
How to build
a Resource table? 18 18

19. Host Bootstrapping and Discovery
Consider H1 that first gets configured in R1
Resource R1
ID (Content or Host)
Owner ID H1
self R5 R5 H1 H1 2 2 1 1 2 2 1 1 2 3 3 R1 R1 R2 R2 R3 R3 R4 R4 19 19

20. Resource table in each router
resource R2
ID (Content or Host)
Owner ID H1 R1
resource R3
ID (Content or Host)
Owner ID H1 R1
resource R4
ID (Content or Host)
Owner ID H1 R1 R5 R5 H1 H1 2 2 1 1 2 2 1 1 2 3 3 R1 R1 R2 R2 R3 R3 R4 R4 20

21. Disconnection of host X Do it in the same way! R5 R5 H1 H1 2 2 1 2 2 13 3 R1 R1 R2 R2 R3 R3 R4 R4 21

22. Content Bootstrapping and Discovery
Use the same approach as host advertisement
resource table
ID (Content or Host)
Owner ID C1 H1 H2 H2 C1 R5 R5 H1 H1 2 2 1 1 2 2 1 1 2 1 3 3 R1 R1 R2 R2 R3 R3 R4 R4 H3 H3

23. One forwarding table does all !!!
For every packet, the destination is either Host ID or Content ID. The router always find the next-hop from the forwarding table. 23 23

24. Packet format
Header
Extension
Payload

25. Header format All packets have the same header structure! Header
| Version 3 bit | Type 5 bits |
| Dest ID 8 bits |
| Src ID bits | |
Type:
Heartbeat: monitor the liveness of router and host
Neighbor: exchange the neighbor info.
Host Discovery: host actively joins or leaves the network
Content Discovery: content adds to or withdraw from the network
Get Content Request
Get Content Respond: reply with content data
ACK

26. Data Transfer and Reliability
Message Forward
Not support Multicast
ARQ Scheme
receive windows
timeout for each data request packet
ACK for routing information packet
NO ACK for data packet 26 26

27. Scenario 2: @host_H1: get (content_C2)27

28. X Scenario 3: @host_H1: get (content_C1) H1 H2 H3 Send C1 H4 Send C128

29. Advantages and Disadvantages
Pros
Simple and Scalable
Efficient: can choose the nearest provider
Automatically forward a packet to other provider if the original one unavailable.
Cons
Throughput is not perfect by using timeout scheme for data packet. 29

30. Content Request Packet
| Version 3 bit | Request |
| Content ID 8 bits |
| Src Host ID bits |
| offset 16 bits |
| size bits |
Header
extension

31. Content Respond Packet
| Version 3 bit | Respond |
| Dest Host ID 8 bits |
| Content ID bits |
| offset 16 bits |
| size bits |
| Flags |
| Payload |
Header
extension

32. Host Discovery Packet | Version 3 bit | Host Discovery | | R2 | | R1 |
| random seq 16 bits |
| Add / DEL |
| HOST ID = H |
| Owner ID =R |
| Len of PATH= |
| R |
Header
extension

33. Content Discovery Packet
| Version 3 bit |Content Discovery |
| R |
| R |
| random seq 16 bits |
| Add / DEL |
| HOST ID = C |
| Owner ID = H |
| Len of PATH= |
| R |
Header
extension