Introduction Definitions Network Why? Coding What?
Network Coding Why? Definitions What? Introduction 11
What is NETWorK COdING Network Coding is a field of information theory and coding theory and is a method of attaining maximum information flow in a network v Network Coding Theory points out that it is necessary to consider encoding/decoding data on nodes in network in order to achieve optimal throughput
What is NETWORK CODING ✓Network Coding is a field of information theory and coding theory and is a method of attaining maximum information flow in a network. ✓Network Coding Theory points out that it is necessary to consider encoding/decoding data on nodes in network in order to achieve optimal throughput. 12
Multicast Problem Butterfly NetworkS: Each A edge's capacity is 1 Max-Flow from a to d B C 015 Max-Flow from a to E Multicast Max-Flow from A to d and E=1.5 Max-Flow for each 15G individua connection is D E not achieved
Multicast Problem • Butterfly Networks: Each edge’s capacity is 1. • Max-Flow from A to D = 2 • Max-Flow from A to E = 2 • Multicast Max-Flow from A to D and E = 1.5 • Max-Flow for each individual connection is not achieved. A B C F G D E 1 1 1 1 1 1 1 1 1 0.5 0.5 0.5 0.5 13
b,(a)b Ahlswede et al (2000) Bb1 C With network coding, every sink obtains the maximum flow b +b2(G b,+b2 E [2]Rudolf Ahlswede, Ning Cai, Shuo-Yen Robert Li, and Raymond W. Yeung. Network information flot
• Ahlswede et al. (2000) – With network coding, every sink obtains the maximum flow. A B C F G D E b1 b2 b1 b1 b2 b1+b2 b2 b1+b2 b1+b2 [2] Rudolf Ahlswede, Ning Cai, Shuo-Yen Robert Li, and Raymond W. Yeung. Network information flow. 14
COPE Y COPE is an opportunistic approach to network coding to increase the throughput of wireless mesh networks Y COPE inserts a coding layer between the IP and MAC layers, which identifies coding opportunities and benefits from them by forwarding multiple packets in a single transmission 3]S. Katti, D Katabi, W. Hu, and R Hariharan, The importance of being opportunistic: Practical network coding for wireless environments
COPE ✓ COPE is an opportunistic approach to network coding to increase the throughput of wireless mesh networks. ✓ COPE inserts a coding layer between the IP and MAC layers, which identifies coding opportunities and benefits from them by forwarding multiple packets in a single transmission. 15 [3] S. Katti, D. Katabi, W. Hu, and R. Hariharan, “The importance of being opportunistic: Practical network coding for wireless environments