This document discusses routing and multicast protocols at the MAC, routing, and application layers. It describes key modules like transmission, receiving, and neighbor list handling at the MAC layer. At the routing layer, it discusses unicast and multicast routing tables, forwarding, tree construction, and session maintenance. The application layer handles data transmission, multicast session initiation and termination, and route repair. It also compares source tree and shared tree approaches, and soft state and hard state maintenance mechanisms.
Report
Share
Report
Share
1 of 17
More Related Content
Multicast routing protocols in adhoc networks
1. T S Pradeep Kumar
VIT Chennai
http://www.nsnam.com
http://www.pradeepkumar.org
2. Medium Access Control (MAC Layer)
◦ Transmission and reception of packets is the main
service
◦ Also arbitration to access the channel
◦ Three modules are handled
Transmission Module
Receiving Module
Neighbor list handler
3. Routing Layer
◦ Formation and maintaining the unicast
session/multicast group
◦ Uses a set of tables, timers and route cache
◦ Unicast Routing information handler
◦ Multicast Routing information handler
◦ Forwarding module
◦ Tree/Mesh construction module
◦ Session Maintenance Module
◦ Route cache maintenance module
4. Application Layer
◦ Data packet transmit/receive controller
◦ Multicast session initiator/terminator
◦ Joining a group
◦ Data packet propagation
◦ Route Repair
6. Type of Node Active Modules
Source/Receiver All Modules
Intermediate Nodes All modules of MAC and routing
Layers
Other Nodes Modules 2,3,8 and optionally
module 4
7. Application Independent / Generic
◦ Based on Topology
Tree based
Source Tree and Shared Tree
Mesh based
◦ Based on initialization of multicast session
Source initiated
Receiver initiated
◦ Based on topology maintenance mechanism
Soft state approach
Hard state approach
8. Tree based
◦ Source Tree based
The source is at the root
◦ Shared Tree based
All the sources share the common tree with a core
node at the root
If there is a single point of failure (if core node failed),
the route construction should happen again
10. Soft state approach
◦ Control packets are flooded periodically to refresh
the route
◦ Packet delivery ratio is high
Hard state approach
◦ Control packets are flooded only during a link break
◦ Packet delivery ratio is low because low control
overhead
11. Source Tree based Shared Tree Based
A single multicast tree maintained
per source
A single tree is shared by all
sources in the tree
Less scalable (increase in number
of sources leads to increase in
trees which affects the bandwidth)
More scalable (performance will
not be degraded when more
multicast sessions or more souces
are added)
More memory is needed at the
source nodes
Less memory is needed as the tree
is shared between the sources
12. Tries to find the nearest forwarding node
rather than the shortest path between source
and receiver
Reduces number of data transmissions
Uses hard state approach (to rejoin multicast
group, the control packets are sent only
during link breaks)
13. Tree initialisation Phase
◦ Join packets
A receiver node floods the join control packets
◦ Reply Packets
The existing members of the tree, on receiving join
packets, respond with Reply control packets
◦ Reserve Packets
When many such reply packets comes to the receiver
nodes, then the receiver node select the minimum hop
count route and send a Reserve Control packet to the
member node.
15. Node R3 Moves, I3
Broadcasts
R3 receives and send a
Reserve packet
Broadcast multicast
scheme
When the node moves,
the upstream node is
responsible for finding
a new route by
flooding with
broadcast-multicast
packets
16. R3, I3 Links fails, R3
sends join and I3 reply
R3 Send Reserve packets
and rejoin the group
Local Rejoin Scheme
The corresponding
sends the join packet if
there is any break in
the link.
It is similar like tree
initialization phase
17. R3 Receives from I2 before I5
and R3 Sends a Reserve packet
I5->I4->I3->I2, sends a Quit
packet and thus a path is pruned
When a tree node or
receiver nodes comes
within the transmission
range of other tree
nodes, the unwanted
tree nodes are pruned
by sending the Quit
messages.