3Com 3CB9LF36T Plumbing Product User Manual


 
14
C
HAPTER
2: R
ELEASE
H
IGHLIGHTS
IGMP
The Internet Group Management Protocol (IGMP) ensures that multicast
traffic is forwarded from the local router to multicast group members on
directly attached subnetworks. The Snooping function monitors IGMP
packets to ensure that multicast traffic is
only
forwarded to areas of the
network that contain multicast group members. Unlike the Distance
Vector Multicast Routing Protocol (DVMRP), IGMP functions do not relate
to multicast packet delivery between routers. IGMP functions include:
Querying
Snooping
10/100 Mbps
Ethernet Port
Monitoring
This feature, which is enabled by default, is designed to:
Monitor 10/100 Mbps Ethernet ports for excessive collisions, multiple
collisions, late collisions, runts, and FCS errors.
Compare these error counters against predetermined thresholds.
Disable a port that reaches an error threshold.
Report the reason that a port is disabled to the Administration
Console, MIB databases, and SNMP traps.
Reenable the port after an initial backoff time interval.
Continue monitoring.
See “Port Monitoring” in Chapter 5 “Ethernet” in the
CoreBuilder 9000
Implementation Guide
for information about the new Ethernet port
monitoring feature.