Switch Management and Operating Concepts
Multicasting
Multicasting is a group of protocols and tools that enable a single source point to send packets to groups of multiple destination points with persistent connections that last for some amount of time. The main advantage of multicasting, when compared to broadcasting, is a decrease in the network load.
•Broadcast packets are sent to all devices on a subnetwork.
•Unicast packets are sent from a single network device to another single network device.
•Multicast packets are sent to a group of network devices.
The following table lists some of the permanently assigned multicast addresses.
Address | Description | |
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224.0.0.0 | Base Address (reserved) | |
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224.0.0.1 | All Systems on this subnet | |
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224.0.0.2 | All Routers on this subnet | |
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224.0.0.3 | Unassigned | |
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224.0.0.4 | DVMRP Routers | |
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224.0.0.5 | OSPF IGP Routers | |
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224.0.0.6 | OSPF IGP Designated Routers | |
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224.0.0.7 | ST Routers | |
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224.0.0.8 | ST Hosts | |
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224.0.0.9 | All RIP2 Routers | |
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224.0.0.10 | All IGRP Routers | |
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224.0.0.11 | Mobile Agents | |
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224.0.0.12 | DHCP Servers and Relay Agents | |
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224.0.0.13 | All PIM Routers | |
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224.0.0.14 | RSVP Encapsulation | |
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224.0.0.15 | All CBT Routers | |
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224.0.0.16 | Designated Sbm | |
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224.0.0.17 | All Sbms | |
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224.0.0.18 | VRRP | |
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224.0.0.19 through 224.0.0.225 except | Unassigned | |
224.0.0.21 | ||
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224.0.0.21 | DVMRP on MOSPF | |
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Internet Group Management Protocol (IGMP)
Multicasting relies on the concept of nodes joining and leaving multicast groups. Nodes use IGMP to join and then leave a multicast group. Based on the IGMP reports the switch receives from the nodes, it can decide whether to forward a multicast packet on a particular interface.
36 | ZT8101 User’s Manual |
