1. MZR: A Multicast Protocol based on Zone Routing
Vijay Devarapalli
Nokia Research Center
Dr. Deepinder Sidhu
Maryland Center for Telecommunications Research
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

2. Presentation Overview
Introduction to MZR
Proactive and Reactive Routing Protocols
Zone Routing Protocol
Details of how MZR functions
Performance Analysis
Conclusions
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

3. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Introduction to MZR:
What is MZR?
It’s a source initiated on-demand multicast routing protocol
Builds a multicast delivery tree rooted at the source based on the zone routing protocol
Does not depend on any underlying unicast protocol for global routing substructure
Why Multicast?
Ad hoc network  collaborative computing
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

4. Proactive versus Reactive
Proactive Routing Protocols
Exchange routing information periodically to maintain an up-to-date routing table
React to each network topology change
Problems:
High percentage of bandwidth used for routing information
Only a small fraction of the control traffic may be used
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

5. Proactive versus Reactive
Reactive Routing Protocols
An initial route discovery process
Minimal reaction to topology change
Problems
Route information may not be available at the time of route request
The route discovery process is typically implemented as a global flood-search procedure
Explosion of control traffic
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

6. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Zone Routing Protocol
Hybrid (proactive and reactive) routing protocol
Proactive procedure limited to node’s local neighborhood (zone)
Global search is carried out by querying selected (border) nodes
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

7. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
Zone Construction and Maintenance
Each node constructs a zone around itself using a pre-configured radius
Zone Routing Table built using ADVERTISEMENT packet
Periodic advertisements keep routing table up-to-date
Interior and Border nodes can be identified using the Zone Routing Table
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

8. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
Multicast Tree Creation
For each multicast session a tree rooted at the source is created.
The tree is identified by <source, group> pair
Multicast route entry consists of:
Multicast session id
<source, group> pair
IP address of upstream node
A list of the downstream nodes
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

9. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
Multicast Tree Creation (continued)
Tree Creation is a two step process:
Step 1: Extend tree inside zone
Source sends a TREE-CREATE to each zone node
As the TREE-CREATE packet is propagated reverse routes are created at each intermediate node
An interested node replies with a TREE-CREATE-ACK
The TREE-CREATE-ACK is sent back through the reverse route
As it propagates, the multicast route entry is completed and activated
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

10. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
Multicast Tree Creation (continued)
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

11. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
Step 2: Extend tree to the entire network
Source sends a TREE-PROPAGATE message to border nodes
On receiving the TREE-PROPAGATE the border node does the following things:
Sends a TREE-CREATE packet to all its zone nodes and the procedure described in Step 1 is followed
Once it is done with the zone nodes it sends a TREE-PROPAGATE message to its border nodes
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

12. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

13. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
Routing Mechanism
Source starts transmitting once the multicast delivery tree is created
Internal nodes of the tree replicate received data packets and send a copy to each node on the downstream list
Transmission to a downstream node is stopped once that node migrates
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

14. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
Maintaining up-to-date routing information
Timer for each route entry
Stale route entries removed on time-out
To keep routes active within multicast session source sends TREE-REFRESH packet
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

15. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
Reaction to Link Breaks
Downstream nodes responsible for detecting link breaks
On detecting a link break the downstream node initiates a global search using the zone routing mechanism
Similar method to Tree creation:
JOIN JOIN-ACK
JOIN-PROPAGATE
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

16. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Details of MZR
Leaving a multicast group
When tree member wants to leave the group it sends an TREE-PRUNE message to its upstream node
The upstream node removes the node from its downstream list
If the downstream list of an intermediate node becomes empty then it sends a TREE-PRUNE to its upstream node
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

17. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Performance Analysis
Simulation Model
50 mobile nodes moving according to the random waypoint model on a 500m x 500m 2D grid
Running time of simulation was 300 seconds
Transmission range is set to 100 meters
Link capacity assumed to be 2 Mbps
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

18. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Performance Analysis
Packet Delivery Ratio (PDR) and Node Mobility
PDR = D / N
D  number of data packets actually delivered to multicast group members
N  total number of packets that were supposed to be delivered
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

19. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Performance Analysis
Packet Delivery Ratio (PDR) and Node Mobility
Packet delivery ratio is almost 100% for slow movement but drops to below 50% at high mobility
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

20. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Performance Analysis
Routing Overhead and Node Mobility
Ratio of control packets sent versus all packets sent
Routing overhead increases with mobility and may reach 40%
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

21. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Performance Analysis
Routing Overhead and Multicast Group Size
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

22. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Performance Analysis
Packet Delivery Ratio and Multicast Group Size
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing

23. MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing
Conclusions
New source initiated, on demand multicast routing protocol for ad hoc networks
Builds a multicast delivery tree and does not depend on any underlying unicast mechanism
Every multicast receiver in the ad hoc network joins in finite time
Scales well for different group sizes and different mobility speeds
MZR: A Multicast Protocol for Ad Hoc Networks based on Zone Routing