Network Routing & Switchig

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  • Topic: Multicast, Routing, Routing protocol
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Mawlana Bhashani Science and Technology University
Department of CSE
Santosh, Tangail-1902

Course Code: CSE-4107
Course Name: Network Routing and Switching.

Assignment No: 01
Name of the assignment: DVMRP, MOSPF, PIM, NEMO, CBT, AODV and Optical Routing. Date of submission: 04-12-12

Submitted to: Submitted by: MD.Mahfuz Reza Md. Harish-Uz-Jaman Mridha Lecturer, 4th Year 1st semester Department of CSE ID: CE-09026 MBSTU Session: 2008-09


1. DVMRP (Distance Vector Multicast Routing Protocol).
2. MOSPF (Multicast OSPF).
3. MBONE (Multicast Backbone).
4. PIM (Protocol Independent Multicast).
5. CBT (Core-Based Tree).
6. NEMO (Network Mobility).
7. AODV (Ad-hoc On Demand Distance Vector Routing) and
8. Optical Routing.

DVMRP (Distance Vector Multicast Routing Protocol)

The Distance Vector Multicast Routing Protocol (DVMRP) is used to share information between routers to facilitate the transportation of IP Multicast packets among networks. It forms the basis of the Internet's multicast backbone (MBONE). Unicast distance vector routing is very simple; extending it to support multicast routing is complicated. Multicast routing does not allow a router to send its routing table to its neighbors. The idea is to create a table from scratch by using the information from the unicast distance vector tables.

Operation: The protocol is based on the RIP protocol for forwarding packets: the router generates a routing table with the multicast group of which it has knowledge with corresponding distances (i.e. number of devices/routers between the router and the destination). When a multicast packet is received by a router, it is forwarded by the router's interfaces specified in the routing table. DVMRP operates via a reverse path flooding technique, sending a copy of a received packet (specifically IGMP messages for exchanging routing information with other routers) out through each interface except the one at which the packet arrived. If a router (i.e. a LAN which it borders) does not wish to be part of a particular multicast group, it sends a "prune message" along the source path of the multicast.

Properties of DVMRP:
* IETF standard for IGP multicast routing
* Based on RPM
* DVMRP is a separate routing protocol
* –  the routers run either RIP or OSPF for unicast routing * –  DVMRP builds its own routing table for it to make multicast routing decision. It doesn’t use the unicast routing table from RIP nor OSPF. Multicast distance vector algorithm uses a process based on four decision-making strategies. Each strategy is built on its predecessor to improve the shortcomings. These are: i) Flooding: Flooding broadcasts packets, but creates loops in the systems. ii) Reverse Path Forwarding (RPF): RPF eliminates the loop in the flooding process. iii) Reverse Path Broadcasting (RPB): RPB creates a shortest path broadcast tree from the source to each destination. It guarantees that each destination receives one and only one copy of the packet. iv) Reverse Path Multicasting (RPM): RPM adds pruning and grafting to RPB to create a multicast shortest path tree that supports dynamic membership changes. Advantage:

* Relatively simple
* Modest processing demands
* Convergence performance
* Periodically flood multicast traffic to rebuild its trees – scalability

MOSPF (Multicast OSPF)

MOSPF (Multicast Open Shortest Path First) is an extension to the OSPF (Open Shortest Path First) protocol that facilitates interoperation between unicast and multicast routers and uses multicast link state routing to create source-based...
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