ECE 544 Protocol Design Project 2016 Haoyuan Xu Pei Peng Shashikanth Rangan

Network Architecture & Topology Assumptions Service Objective

Assumptions Unreliable network with packet loss prob. per link of p Each end node is attached to only one router All links have same characteristics (i.e. hop cost 1 and same MTU 1500 bytes) Small maximum number of nodes (i.e. 50) Underlying medium is ethernet

Protocol Concept Overall concept of your proposed protocol Service provided : k out of n multicast Control plane : OSPF header, Hello msg, Link State Update, Link State Request, IGMP, Back to N/ACK Data Plane : Data packet containing information about k, sender and group ip address. Algorithm : Dijkstra(slight modification), paths are chosen by algorithm created by us. 4

Syntax - Packet Formats OSPF Header Figure 1

Packet Formats (Contd) Version- 2 (1-byte) Type- It specifies the type of OSPF packet. There are 5 different types of OSPF packets. (1-byte) Packet Length- Total length of the OSPF packet (2-bytes) Router ID- The Router ID of the advertising router Checksum- Standard IP Checksum of OSPF packet excluding Authentication field (2-bytes)

Packet Formats (Contd) OSPF Hello Msg Figure 2

Packet Formats (Contd) Hello Interval- Interval at which Hello packets are advertised. By default, 10 seconds for point-to-point link and 30 seconds for NBMA/Broadcast links (2-bytes) Options- The local router advertises its capabilities in this field. (1-byte) Rtr Pri- The Priority of the local router. It is used for DR/BDR election. If set to 0, the router is ineligible for the election. (1-byte)

Packet Formats (Contd) Dead Interval- The Dead Interval as requested by the advertising router. By default, 40 seconds for point-to-point link and 120 seconds for NBMA/Broadcast links (4-bytes) Designated Router- The IP address of the current DR. Set to 0.0.0.0 if no DR is elected yet. (4-bytes)

Packet Formats (Contd) Link State Request Packet Figure 3

Packet Formats (Contd) LS Type- Type of LSA requested (4-bytes) Advertising Router- Router ID of the requesting router (4-bytes)

Packet Formats (Contd) # LSAs LSAs Figure 4 Link State Update Packet Contains two fields #LSA’s - Number of LSAs within an LSU packet (4-bytes) LSAs- The complete LSA is encoded within this field. The LSU may contain single or multiple LSAs.

Packet Formats (Contd) LSA Header Figure 5 Link State Acknowledgement Packet LSA Header- List of LSA Headers being acknowledged.

Packet Formats (Contd) LSA Packet Figure 6 14

Packet Formats (Contd) Multicast Data Packet Type k Sequence number Group IP Address Sender’s IP Address Data

Packet Formats (Contd) IGMP (version 2) Figure 7

Packet Formats (Contd) IPv4 Header Figure 8

Packet Formats (Contd) Control Packet Multicast Group IP k= Sender’s IP Control Data Control Data: (R1,R2) (R2,R3) (R2,R4)

Routing Algorithm Routing Algorithm Hello message IGMP v2 (join message) LSA MOSPF in each edge-router hello message: know its neighbor; IGMP v2: know multicast group member. MOSPF in each edge-router: build the tree. And only need to know how many members in each nodes.(n nodes, if k=3, (n*(n-1)*(n-2)=)O(n^3))

Routing Algorithm Routing table structure and contents Router Table Multicast table(edge-router) port ip_address Live_time (sec) 1 xxx.xxxx.xxx.xxx 2 Multicast Group NO # of hosts Member Address[] port 2 [IP1,IP2] 1 3 [IP1,IP2,IP3]

Routing Algorithm Routing table structure and contents MOSPF Tree Table (similar to OSPF) Dest Node Distance Prev hop # of Group 1 # of Group 2 D 4 C 2 3 B null A 1 S

Routing Algorithm Diagram showing working of Algorithm step Confirmed tentative 1 (A,0,-,3,2) (B,1,B,1,0) (C,1,C,-,-) 2 (D,2,B,2,3) (C,2,B,-,-) 3 (C,1,B,-,-) (D,3,C,2,3) 4 - root When select node to build the tree, it will choose the shortest node which has more links connected.

Routing Algorithm Routing Algorithm Find the best k out of n Sort the distance at tree table in increasing order. Choose top 2k nodes that have the multicast group member. Calculate the total distance for all cases, choose the best one. ( same link path, minus # of group member -1) MOSPF in each edge-router: build the tree. And only need to know how many members in each nodes.(n nodes, if k=3, (n*(n-1)*(n-2)=)O(n^3))

Routing Algorithm Routing Algorithm Find the best k out of n K = 2 In order to choose D1,D2 Instead of D2, D3 D1,D2 cost 3, D2,D3 cost 4 MOSPF in each edge-router: build the tree. And only need to know how many members in each nodes.(n nodes, if k=3, (n*(n-1)*(n-2)=)O(n^3))

Routing Algorithm Discuss complexity and performance of routing algorithm Complexity for building trees: O(nlogn + E) Performance for building trees: Cost is not small but it don’t influence much. Since all of these is down before multicast.

Data Plane Forwarding forwarding table Multicast Group IP k=? Sender’s IP port 1 3 11111.1.1.1.1 0, 2 2 222.2.22.222

Data Plane Forwarding copy-forward mechanism Each router have a small buffer the packet just sent will live in some time.(like 2RRT...) Send it again after received ACK request. Drop it if no ACK request(time out).

Data Plane Forwarding Diagram showing forwarding of packets at any given router Multicast Group IP k=? Sender’s IP port Source port 11.111.11.12 3 34.123.132.23 0, 2 02.21.31.1 2 23.42.5.2 1

K=2 R2 R5 D1 S R1 R3 R6 D2 R4 R7 D3 Following the forwarding table According to received control packet and the packet from upper router D1 and D2 is better, and the path is selected R2 R5 D1 copy1 copy1 copy1 (R2,R5) (R3,R6) S R1 R3 R6 D2 copy2 copy2 copy2 (R2,R5) (R3,R6) (R1,R2) (R2,R5) (R1,R3) (R3,R6) R4 R7 D3

K=3 Receiving the forwarding table and the packet from upper router Following the forwarding table According to the tree, this router selects the best path R2 R5 D1 copy1 copy1 copy1 (R2,R5) (R3,R6) (R4,R7) S R1 R3 R6 D2 copy2 copy2 copy2 (R1,R2) (R2,R5) (R1,R3) (R3,R6) (R1,R4) (R4,R7) (R2,R5) (R3,R6) (R4,R7) Send to D3 R4 R7 D3 copy3 copy3 copy3 (R2,R5) (R3,R6) (R4,R7)

K=2 According to the tree, this router choose D1 and D2, and the path R3 S R1 R4 D1 copy1 copy1 (R1,R3) (R3,R4) (R3,R5) (R5,R6) R2 D2 (R3,R4) (R3,R5) (R5,R6) Copy the packet copy2 R5 R6 copy2 copy2 (R5,R6) Send the packet Smaller number is better D3

K=3 According to the tree, this router choose the path R3 S R1 R4 D1 copy1 copy1 (R1,R3) (R3,R4) (R3,R5) (R5,R6) R2 D2 (R3,R4) (R3,R5) (R5,R6) Copy the packet copy2 R5 R6 copy2 copy2 (R5,R6) Copy the packet D3 copy3

Summary Key protocol design features (recap) Performance Each edge-router have its own tree Build the tree before need to multicast packets Performance Delay is small, since we only need to cost the time to find path. Implementation complexity The Dijkstra algorithm complexity is O(nlogn+E). The path search algorithm: Sort complexity is O(nlogn) Find path complexity is O((2k)^k) computing requirement is needed 33