
Network-Coding Multicast Networks With QoS Guarantees Abdullah Şahin Hasan Saygın Arkan 10.01.2010
Introduction • “Network-Coding Multicast Networks With QoSGuarantees” • Xuan, Y.: Lea, C.-T. • IEEE/ACM Transactions on Networking • 30 August 2010 • Related Work • Terms • QoS, Network Coding, unicast, multicast…
Unicast & Multicast Congession
Problem Definition • Admission Control – How? • New QoS Architecture – Non-Blocking Network! • No admission control • Low throughput for multicast • Impractical • Data Transmission • Transmission in Client – Local Server TRIVIAL • Transmission in Backbone PROBLEM!
Problem Definition • Transmission in Backbone PROBLEM!
Unicast Data Packet Data Packet
Multicast Data Packet Data Packet Data Packet Data Packet
Unicast Solution • tij= traffic rate from i edge to j edge • αi= ingress traffic & βi = egress traffic • (αi, βi) = (Θ αi’ , Θ βi’) • Task is maximizing Θ Edge Router αi= ingress traffic βi = egress traffic
Unicast Solution • Σtij< αi’ • Σtij< βi’ • Not Applicable on Multicast • α = β for unicast, but not for multicast Edge Router
Multicast Solution G = multicast edge group = { sg, D(g), tg } source, destination set, data rate Binary Vectors: ϒg(i) = 1, if i = sgδg(j) = 1, if j € D(g) 0, otherwise 0, otherwise
Multicast Solution • Σϒg(i) . tg< αi’ - ingress traffic • Σδg(j). tg< βi’ - egress traffic • tij = Σ(δg(j) .ϒg(i) . tg)
Optimal Routing j i xije
Optimal Routing • For IP networks • Calculation on weights • MPLS-Type Explicit Routing Networks • Arbitrarily chosen nodes, and calculation of max loaded link
Numerical Results • Constraint-Based Routing Approach • Non-Blocking Based Approach • 15 Nodes, 62 directed links, capacity of 300. • 10 consecutive rejects = fully loaded • Number of receivers per multicast flow is random (binomial distribution [2, N-1] , N is total edge
Numerical Results • Nonblocking Multicast Networks • b/a ratio, average fan-out = 3, 15 edge nodes
Numerical Results • Nonblocking Multicast Networks • b/a ratio, average fan-out = 4, 15 edge nodes
Numerical Results • Nonblockingvs CBR • 5 edge nodes, average fan-out = 3
Numerical Results • Nonblockingvs CBR • 15 edge nodes, average fan-out = 3
Numerical Results • Nonblockingvs CBR • 15 edge nodes, average fan-out = 4
Conclusion • Better to have admission control at the edge, NOT inside it! • Non-Blocking removes that need • Main Problem – low throughput • Optimal Paths in Unicast = Optimal Paths in Multicast Nonblocking with Network Coding