Installation guide

Network Setup 4-159
4.10.4.1 Editing a Port Instance Configuration
To edit and reconfigure Port Instance parameters.
1. Select a row from the port table and click the Edit button.
Most of the MSTP Port Instance parameters can be reconfigured, as indicated below.
4.11 Configuring IGMP Snooping
Internet Group Management Protocol (IGMP) is used by both IP hosts and multicast routers. IP hosts use
IGMP to report their multicast group memberships to any immediate-neighboring multicast router. Routers
use the query message on its interface to solicit multicast group membership information from clients.
IGMP snooping is the process of listening to IGMP traffic. IGMP snooping allows the switch to listen in on
an IGMP conversation between hosts and routers by processing layer 3 packets IGMP packets sent in a
multicast network.
The goal of IGMP is to learn multicast router ports and snoop IGMP join requests/reports to build a portal list
to forward multicast packet to interested hosts only on that Portal, thus optimizing the flooding of multicast
packets.
IGMP snooping allows the switch to manage multicast traffic based on groups of IGMP hosts on a per-portal
basis. IGMP snooping keeps track of hosts interested in a multicast group and on the portal it is associated
and forwards multicast packets to portal on which the host is connected.
In the case of IP multicast traffic, an IGMP supported switch provides the benefit of conserving bandwidth
on those network segments where no node has expressed interest in receiving packets addressed to the
group address. This is in contrast to normal switch behavior, where multicast traffic is typically forwarded
on all interfaces.
IGMP basically operates as follows:
Port Instance ID Read only indicator of the instance ID used as a basis for other modifications.
Port Index Read only indicator of the port index used as a basis for other modifications.
Port Priority If necessary, change the port priority value for the bridge. The lower the priority, a
greater likelihood of the port becoming a designated port.
Admin Internal Path
Cost
Displays the configured Admin Internal Path Cost of a port. A value of 0 indicates
that the user has not configured a path cost.
Operational Internal
Path Cost
Displays the Operational Path Cost of a port. This displays the default cost if
AdminInternal Path Cost is 0.