HBH also provides a better network utilization as it is able to construct recur- sive unicast trees minimizing packet duplication. This is an advantage if the network bandwidth is scarce. The advantage of HBH grows with 14 larger and more connected networks. Bhattacharyya Sprint Labs. Receiver average delay 16 7. Apostolopoulos, R. Guerin, S.
Kamat, and S. Bates, R. Chandra, D. Katz, and Y. RFC , Feb. Bhattacharyya, C. Diot, L. Giuliano, R. Rockell, 2 J. Meylor, D. Meyer, G. Shepherd, and B. Work in progress: Number of receivers draft-ietf-ssm-overview Cain, S. Deering, W. Fenner, I. Kouvelas, and b node random topology.
Work in progress: draft-ietf-idmr-igmp-v Figure 8: Average delay experienced by the re- [5] S. Host Extensions for IP Multicasting. RFC ceivers. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. The PIM architecture for wide-area multicast routing. Diot, W. Dabbous, and J.
Multipoint communication: A survey of protocols, functions and mechanisms. Diot, B. Levine, B. Liles, H. Kassem, and D. Farinacci, A. Helmy, D. Deering, M. Handley, V. Sharma, and L. Protocol Independent join S, B afterwards. RFC , June Fall and K. The ns Manual.
In this case B discards the message and [11] B. Fenner, M. Handley, H. Holbrook, and I. B, there is two possibilities: R is a new receiver in which Work in progress: case B inserts R in its MFT and sends a f usion message draft-ietf-pim-sm-v2-new RFC , Nov.
If B is not a [13] R. Work in progress: distribution tree in which case B creates a MCT containing draft-finlayson-umtp R 4 , or B was already in the distribution tree but was not [14] R. Finlayson, R. Perlman, and D. Work in progress: and B simply refreshes its MCT 6. If R is not present draft-finlayson-mboned-autotunneling Hanks, T. Li, D. Farinacci, and P. RFC , Oct.
Holbrook and D. IP multicast receive data through B, so B becomes a branching node. The Sept. Liefooghe and M. An architecture for B maintains in its MFT - the nodes for which B is branch- seamless access to multicast content. In IEEE ing node.
Conference on Local Computer Networks, Nov. Meyer Editor and B. Fenner Editor. Work a f usion S, R, Rn from node Bp. If the message is not in progress: draft-ietf-msdp-spec If [19] J. End-to-end routing behavior in the 2.
A marked entry in the MFT is used to tree message internet. MFT if it was not previously present. Stoica, T. Ng, and H. Consequently, Bp recursive unicast approach to multicast. Thaler, M. Talwar, L. Vicisano, and D. Bp entry , but its t1 timer is kept expired 4. Work in progress: If afterwards Bp the node that produced the f usion for draft-ietf-mboned-auto-multicast Fur- source has packets to send, it periodically broadcasts to the en- thermore, typical multicast trees usually require a global rout- tire network a member advertising packet, called a J OIN R E - ing substructure such as link state or distance vector.
This periodic transmission refreshes the membership quent exchange of routing vectors or link state tables, triggered information and updates the route as follows. Limited bandwidth, constrained power, node ID i. If it does, the node and improve scalability. It uses the concept of forwarding realizes that it is on the path to the source and thus is part of the group [5], a set of nodes responsible for forwarding multicast forwarding group.
By maintaining is thus propagated by each forwarding group member until it reaches the multicast source via the shortest path. Why a Mesh? We have visualized the forwarding group concept in Fig. Example The forwarding group is a set of nodes in charge of forward- ing multicast packets. It supports shortest paths between any Fig. When receivers send and another receiver. Suppose the route from arrivals carry no new source information. After the group establishment and route construction pro- cess, a multicast source can transmit packets to receivers via selected routes and forwarding groups.
Periodic control pack- ets are sent only when outgoing data packets are still present. The Forwarding Group Concept. An Example of a Join Table Forwarding. When receiving a multicast data packet, a node forwards it F.
Unicast Capability only if it is not a duplicate and the setting of the FG Flag for the multicast group has not expired. This procedure min- One of the major strengths of ODMRP is its unicast rout- imizes traffic overhead and prevents sending packets through ing capability. Other ad hoc multicast routing protocols such as AM- D. If a multicast source wants to leave the protocols. If a III. The simulator is implemented within the Global Mobile Nodes in the forwarding group are demoted to non-forwarding Simulation GloMoSim library [18].
Our simulation models a network E. Multiple runs with different following data structures. For each multicast A free space propagation model [16] with a threshold cutoff group the node is participating in, the source ID and the is used in our experiments.
In the radio model, we assume the ability of a ra- a source within the refresh period, that entry is removed dio to lock on to a sufficiently strong signal in the presence from the Member Table.
The IEEE The medium access control protocol. Forwarding Group Table : When a node is a forwarding group node of the multicast group, it maintains the group One multicast group with a single source is simulated. The information in the Forwarding Group Table.
The size of cast group ID and the time when the node was last re- data payload is bytes. Multicast member nodes are ran- freshed is recorded. Members join the Message Cache : The Message Cache is maintained by multicast group at the start of the simulation and remain as each node to detect duplicates. When a node receives a members throughout the simulation.
A node randomly selects a destina- the sequence number of the packet. Note that entries in tion and moves towards that destination at a predefined speed. After be- First In First Out can be employed to expire and remove ing stationary for the pause time, it selects another destination old entries and prevent the size of the Message Cache to and repeats the same process.
Mobility speed is varied from 0 be extensive. The metrics used in ODMRP evaluation are: 1 2 members Packet Delivery Ratio: The number of data packet deliv- 5 members 10 members 20 members 30 members ered to multicast receivers over the number of data pack- ets supposed to be delivered to multicast receivers.
In addition to bytes of control packets e. Packet Delivery Ratio. Simulation Results 10 members 20 members 30 members 0. The size of multicast group is varied to examine the scalability of the protocol. Having only two 0. In other words: when it receives an IP packet it has to look at the destination address, check the routing table and figure out the next hop where to forward the IP packet to.
We use routing protocols to learn different networks and to fill the routing table. Above we see R1 who wants to deliver an IP packet to destination 2. It checks its routing table, finds an OSPF entry with R1 is now able to forward the IP packet towards the destination. Everything I explained above applies to unicast traffic. What about multicast traffic? Above we see R1 who receives a multicast packet from some video server, the destination address is The routing table however is a unicast routing table.
To route our multicast traffic, we need to use a multicast routing protocol. There are two types of multicast routing protocols:. Dense mode multicast routing protocols are used for networks where most subnets in your network should receive the multicast traffic. When a router receives the multicast traffic, it will flood it on all of its interfaces except the interface where it received the multicast traffic on.
Above we have a video server sending multicast traffic to R1. When R1 receives these packets, it will flood them on all of its interfaces. R2 and R3 will do the same so our two hosts H2 and H3 will receive the multicast traffic.
This happens when:. Above we see R1 that receives the multicast traffic from our video server.
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