A combinational media access protocol for multicast traffic in single-hop WDM lans

Student : T.H LinTeacher : H.T Wu

Date : 7.28

Outline Introduction The architecture of single-hop

WDM networks Protocol The combinational multicast

schedule (CMS) Simulation Results Conclusions

Introduction

Using reservation-based protocol Partitioning multicast group

Using pre-allocation-based protocol

The architecture of single-hop WDM networks The Passive Star Coupler to connect N

nodes. PSC is an N * N broadcast-and select

device interconnected through the optical fibers.

Each node contains one pair of FT-FR to collect the status of multicast traffic, and one pair of FT-TR to access data channel.

The architecture of single-hop WDM networks

The network is packet-switched with fix-size packets and operates in a slot mode.

The buffer at each node is assumed toN-1 queues, one dedicated queue and to allocate one queue for multicast transmission.

The architecture of single-hop WDM networks

Collision The arbitration procedure can avoid.

Destination conflict The receiver wavelength allocation map.

Multicast Traffic Each multicast p

acket has its own value of M.

M>Md perform multicast transmission.

M<Md the packet is treated as the unicast packet.

Protocol

The combinational media access protocol combines the unicast-based protocol and the Multicast Slot Reservation in the FT-TR architecture.

The Unicast-Based Protocol Each node is assigned Ω slots per

cycle and idle for the remaining N- Ω slots.

The Multicast Slot Reservation

IF M < Md, the MSR replicates the packet and transmits the replicated packets from the multicast source node to members of the multicast group individually.

IF M > Md, the MSR makes the reservation of the home channel of the multicast source node.

The Multicast Slot Reservation

Control Channel Access

Each node transmit a control packet via the round-robin TDMA.

The Arbitration Procedure

The request for multicast transmission has the higher priority to reserve the home channel and can be issued at any time slot.

The request for unicast transmission has the lower priority to reserve the channel and be issued according to the unicast protocol.

The combinational multicast schedule (CMS) After receiving the control packet, all

nodes execute the Combinational Multicast Schedule (CMS) at each time slot.

Simulation result The parameters are N=50 network

nodes , Ω= 25 wavelengths. The buffer size of the dedicated queue

per node is 100. |G| and S are the normal distribution

with mean of 5 nodes The nodes in the multicast group G are

randomly chosen from the uniform distribution [0,N-1]

Packet generation follows the Poisson arrival process with parameter q = 0.1.

The multicast packet with prob p and the unicast packet with prob 1-p

Md = 0 means the separate scheduling of unicast and multicast traffic.

Md = 100 means the scheduling of multicast traffic as unicast traffic.

Network throughput

The expected number of transmitted packets per time slot.

Packet delay The number of time slots elapsed from the

slot entering the network to the slot leaving the network.

Conclusions

Md needs to be analyzed in detail to optimize the performance of the protocol.

Reference

W. Y. Tseng and S. Y. Kuo, “A Combinational Media Access Protocol for Multicast Traffic in Single-Hop WDM LANS,” GLOBECOM’98

W. Y. Tseng, C. C. Sue and S. Y. Kuo, “Performance Analysis for Unicast and Multicast Traffic in Broadcast-and-Select WDN Networks,” 1999