MAC Notification Port Settings
To change MAC notification settings for a port or group of ports on the Switch, click Port Settings in the MAC Notification folder, which will display the following screen:
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| Figure 6- 14. MAC Notification Port Settings and Port State Table |
The following parameters may be set: |
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| Parameter | Description |
| Unit | Choose the Switch ID number of the Switch in the switch stack to be modified. |
| From…To | Select a port or group of ports to enable for MAC notification using the pull down menus. |
| State | Enable MAC Notification for the ports selected using the pull down menu. |
Click Apply to implement changes made. |
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6-10 IGMP
Computers and network devices that want to receive multicast transmissions need to inform nearby routers that they will become members of a multicast group.The Internet Group Management Protocol (IGMP) is used to communicate this information. IGMP is also used to periodically check the multicast group for members that are no longer active.
In the case where there is more than one multicast router on a subnetwork, one router is elected as the ‘querier’.This router then keeps track of the membership of the multicast groups that have active members.The information received from IGMP is then used to determine if multicast packets should be forwarded to a given subnetwork or not.The router can check, using IGMP, to see if there is at least one member of a multicast group on a given subnetwork. If there are no members on a subnetwork, packets will not be forwarded to that subnetwork.
IGMP Versions 1 and 2
Multicast groups allow members to join or leave at any time. IGMP provides the method for members and multicast routers to communicate when joining or leaving a multicast group.
IGMP version 1 is defined in RFC 1112. It has a fixed packet size and no optional data.
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