
IGMP Snooping
The IGMP Snooping allows you to view and change the IGMP Snooping administrate status.
IP traffic can be transmitted in one of either three ways: unicast (one sender to one receiver), broadcast (one sender to all members on the network) or multicast (one sender to a group of hosts). IGMP is a
Multicast addresses are Class D IP address, from 224.0.0.0 to 239.255.255.255. These addresses are also referred to as Group Destination Address (GDA). Each GDA address is associated with one MAC address. The GDA MAC address is constructed by joining 01:00:5E and the last 23 bits of the GDA multicast IP address in Hex. For example, GDA 224.1.1.1 corresponds to MAC address 01:00:5E:01:01:01
A
Figure 6-6 IGMP Snooping Dialog
Item
Description
DSLAM IGMP Snooping Status | Specified whether or not IGMP Snooping is to be enabled in the system. |
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(Ethernet) Port ID | This specifies the network port interface. |
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VPI/VCI | This specifies the virtual path, circuit identification for the PVC in the port. |
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IGMP Snooping Status | A Bridge Port, for which IGMP Snooping needs to be enabled or disabled. |
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Leave Mode | IGMP Snooping Leave message processing mode for the port. |
| If the mode is set to ‘Normal’, the Leave message is forwarded to the Querier and then |
| based on the Query received from Querier the Leave processing is triggered. |
| If the mode is set to ‘Fast’, the port is immediately deleted from that multicast group on |
| Leave message reception and then the Leave message is forwarded. The mode should |
| be set to ‘Fast’ for a port only if there is one host behind the port. This is because if |
| there are multiple hosts behind the port then it will lead to traffic disruption for other |
| hosts who might still be listening to that multicast group. |
| If mode is set to ‘FastNormal’, the Leave message is forwarded and the Leave |
| processing is triggered immediately without waiting for any trigger from the Querier. |
| ‘FastNormal’ mode thus saves the delay (equal to the time taken for Leave message to |
| reach router and Querier processing time for it and the time taken for Query to reach |
| IGMP Snoop module) in Leave processing. |
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| Table |
NCT480 IP DSLAM User Guide | YML856 Rev3 |
84 | www.netcomm.com.au |