Seminar on Byzantine-ResilientSecure Multicast Routing in Multi-hop Wireless Networks


  Multicast Routing in Multi-hop Wireless Networks[.pdf (Size: 1.27 MB / Downloads: 2)
INTRODUCTION

Multicast routing protocols deliver data from a source to multiple destinations organized in a multicast
group. Several protocols were proposed to provide multicast services for multi-hop wireless networks.
These protocols rely on node cooperation and use flooding [I], gossip [2], geographical position [3], or
dissemination structures such as meshes [4], [5], or trees [6], [7].

NETWORKA ND SYSTEM MODEL

Network Model
We consider a multi-hop wireless network where nodes participate in the data forwarding process for
other nodes. We assume that the wireless channel is symmetric. All nodes have the same transmitting
power and consequently the same transmission range. The receiving range of a node is identical to its
transmission range.
Nodes are not required to be equipped with additional hardware such as GPS receivers or tightly
synchronized clocks. Also, nodes are not required to be tamper resistant: If an attacker compromises a
node, it can extract all key material, data or code stored on that node.

Multicast Protocol

We assume a tree-based on-demand multicast protocol such as [6]. The protocol maintains bi-directional
shared multicast trees connecting multicast sources and receivers. Each multicast group has a corresponding
multicast tree. The multicast source is a special node, the group leader, whose role is to eliminate stale
routes and coordinate group merges. Route freshness is indicated by a group sequence number updated
by the group leader and broadcast periodically in the entire network. Higher group sequence numbers
denote fresher routes.
The main operations of the protocol are route discovery, route activation and tree maintenance. During
route discovery a node discovers a path to a node that is part of the multicast tree. A requester first
broadcasts a route request message that includes the latest known group sequence number. The route
request message is flooded in the network using a basic flood suppression mechanism and establishes
reverse routes to the source of the request. Upon receiving the route request, a node that is part of the
multicast tree and has a group sequence number at least as large as the one in the route request, generates
a route reply message and unicasts it on the reverse route. The route reply message includes the last
known group sequence number and the number of hops to the node that originated the route reply.
During route activation, the requester selects the freshest and shortest route (i.e., with the smallest
number of hops to the multicast tree) from the routes returned by the route discovery operation. The
requester activates that route by unicasting a multicast activation message.