MQ ： An Integrated Mechanism for Multimedia Multicasting

De-Nian Yang, Wanjiun Liao, Member, IEEE, and Yen-Ting Lin

IEEE TRANSACTIONS ON MULTIMEDIAVOL. 3, NO. 1, MARCH 2001

Outline Introduction RSVP with SPM 、 QoSM MQ ： Multicast with QoS

Tree Construction Tree Maintenance Tree Pruning Tree Reshaping Loop Free Control QoS Metrics

Performance Evaluation Conclusions

Introduction Multicast ：

A packet contains a class D group address in the destination address field of its IP header.

Quality-of-Service (QoS) ：A bound on delay 、 jitter 、 loss ratio or bandwidth

Introduction QoS routing ：

Determine a feasible path which satisfies the QoS constraint of a data flow (source)

Make efficient use of network resources Resource reservation for QoS ：

Sender-oriented Receiver-oriented ： RSVP

RSVP (ReSerVation Protocol)

RSVPDaemon

Application

PolicyControl

AdmissionControl

Packet Classifier

Packet Scheduler

Data

RSVP (ReSerVation Protocol)

Sender

Receiver#1 Receiver#2 Receiver#3

Path

Path

PathResv

Resv

Resv

Reservation request merges as

it travels up the multicast tree.

RSVP with Shortest Path Multicast

PathPath

Fail

MOSPF ：

RSVP with QoS Multicast Routing

Path

Path

Fail

QOSPF ：

MQ ： Tree Construction The sender multicasts Flow_Ad message

through the shortest path delivery tree to all flow recipients.

The receiver sends a Join_Request message back, and it travels upstream only as far as the closest point of the delivery tree where the requested reservation is met, from where a Join_Ack message is returned.

MQ ： Tree Construction The breakout router, the router which is

insufficient to meet the requested QoS, uses QoS routing to determine a new feasible path.

If such a path is found, the router forwards the request toward the new path and waits for an acknowledgement; otherwise returns a Join_Fail message.

Upon receiving a Join_Fail message, the router acts as a breakout router, using QoS routing to determine a path.

MQ ： Tree Construction This operation repeats until :

An on-tree router located at the joining path has found a path based on QoS routing and has received a Join_Ack from the new path.

All the on-tree routers have failed to find a path, causing the recipient to receive a Join_Fail.

Upon receiving a Join_Ack, the breakout router Forwards the Join_Ack downstream, and Sends a ResvRev (reservation remove) message

upstream in the old path to relinquish resources.

MQ ： Tree Construction

Flow_Ad

Flow_Ad

Join_Request(1)

Join_Request(1)

Join_Request(1)

Join_Request(1)

Join_Ack(2)

Join_Ack(2)

Join_Ack(2)

Join_Ack(2)

MQ ： Tree Construction

Join_Request

(1)Join_Ack

(2)

Join_Ack(2)

Join_Ack(2)

Join_Ack(2) Join_

Request(1)

Join_Request

(1)

ResvRev(3)

MQ ： Tree Construction

Join_Request

(1)

Join_Request

(1)

Join_Fail(2)

MQ ： Tree Maintenance Flow_Ad ： Sent by a source on three

occasions Periodic distribution Whenever there is a change in the source And per request (Flow_Solicit)

Refresh ： Sent by a receiver periodically To keep reservation alive (TearDown) To request a change in QoS

MQ ： Tree Pruning

ResvRev

Shrink

Shrink

MQ ： Tree Reshaping 1. Employs QoS routing with the maximum

reserved bandwidth among all the downstream as the QoS metric to determine a feasible path.

2. Sends an Off_Tree_Query to the new path. The hob count field of the message is incremented by one whenever a router is traversed. The on-tree router receives the message and responds with an Off_Tree_Reply of which the hob count field is copied from the Off_Tree_Query when QoS metric satisfied, or set to infinity otherwise.

MQ ： Tree Reshaping 3. Sends an On_Tree_Query message which

travels upstream along the multicast tree until reaching an on-tree router with more than one downstream interface, from where an On_Tree_Reply with a copy of the hob count of the On_Tree_Query is returned.

4. Upon receipt of both returned messages, the reshaping router compares the hob count values. Only when the Off_Tree_Reply is smaller will the tree be reshaped by using Join_Request 、 Join_Ack and ResvRev messages.

MQ ： Tree Reshaping

On_Tree_Query

On_Tree_Query

Off_Tree_Query

Off_Tree_Reply

On_Tree_Reply

On_Tree_Reply

Join_Request

Join_Ack

ResvRev

ResvRev

MQ ： Loop-Free Control

Join_Request

Join_Request

Join_Request

Join_Fail

Join_Fail

Join_Request

Join_Request

Join_Request

Join_Fail

Join_Fail

Join_RequestJoin_Ack

Join_Ack

ResvRev

ResvRevJoin_Ack

ResvRev

ResvRev

MQ ： QoS Metrics

100ms

120ms

80ms

40ms

R3Succeed

R4 Fail !!

R1Succeed

R2 Fail!!

1.0 Mbps100ms

1.5 Mbps120ms

(1.5,30)

(1.5,20)

1.5 Mbps70ms

R2Succeed

Simulation Setup

Flat graph model with 100 nodes

Hierarchical graph model with 100 nodes

Simulation Setup For an edge between pairs of nodes

(u,v), the edge probability is given ：P(u,v)=β*exp(-d(u,v)/αL), where 0< α,β≦1 and d(u,v) is the Euclidean distance from u to v.

α↑ : (no. of connections of distant nodes)↑

β↑ : (the edge densities)↑ We use (α,β)=(0.2,0.2) here.

Performance Metrics We compare ：

1. RSVP with SPM ： MOSPF (hob count) 2. RSVP with QoSM ： QOSPF (hob count,

bandwidth) 3. MQ ： (hob count, bandwidth)

We measure ： 1. Blocking Probability 2. Protocol Overhead 3. Resource Utilization

Blocking Probability

Resource Utilization

Overhead Comparison

Conclusions Being a truly receiver-initiated, soft

state, and integrated scheme for multicast QoS services, MQ demonstrates 1. lower blocking probability for users to join

the group of interest with requested QoS, 2. much reduced protocol overhead, and 3. more efficient resource utilization, as

compared to traditional approaches.