Device Management
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Specification of list parameters:
Header entry
Description
Port
Display the serial number of ports of the switch.
Role
Display the role of port: Root, Designed, Alternate, Backup and --
. “--”
indicates that the port is not connected or that the STP function of switch
is disabled.
Header entry
Description
State
Display the status of the port: Forwarding, Learning, Listening, Blocking,
Discard, and Disable.
Link Status
Display the rate and duplexing mode of the port. Where, “--”indicates
that the port is not connected or negotiation fails.
Path Cost
Display the path cost of the port.
Priority
Display the priority of the port.
Loopback
Status
Display whether loop takes place in the downstream device of the port; if
yes, display “Active”, if not, display “--”.
8.4 IGSP
IGSP (Internet Group Management Protocol Snooping, IGMP Snooping) is a multicasting
constraint mechanism running on the layer-2 device, and it is used to manage and control
the multicasting groups.
The layer-2 device running the IGMP Snooping analyzes the received IGMP messages,
establishes mapping relationship for the ports and MAC multicasting addresses, and
forwards multicasting data as per such mapping relationships.
When the layer-2 device is not running IGMP snooping multicasting data are broadcast on
layer 2. After layer-2 device runs IGMP snooping, the multicasting data of known
multicasting groups will not be broadcast on layer 2, instead the data will be multicast to the
designated receiver; however, the unknown multicasting data will still be broadcast on layer
2.
Primary function of IGMP snooping is to finish dynamic registration of layer-2 multicasting
on the switch. To implement layer-2 multicasting by enabling IGMP snooping, IGMP shall be
implemented on both the host and router, the switch is just to dynamically maintain the
