3Com 4007, Command Reference Manual

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ip multicast dvmrp
Layer 2
Switching
Modules
✓
Multilayer
Switching
Modules
routeDisplay
Displays IP multicast route information that a Multilayer Switching
Module has learned via DVMRP protocol communication.
Valid Minimum Abbreviation
ip m d r
Important Consideration
■
The module uses the information in this routing table to forward IP
multicast traffic that may receive in the future. The routing table does
not reflect the actual traffic that has been received. For that
information, select the
ip multicast dvmrp cache
option.
Fields in the IP Multicast DVMRP Route Display
Field Description
Origin IP address of the subnetwork that contains an IP multicast
source, followed by the subnetwork mask.
Gateway IP address of the routing interface that lies upstream of
the module on the path back towards an IP multicast
source. If the source subnetwork is connected directly to
your module, this field contains a dash (--).
Metric Number of hops from your module back to the origin
subnetwork. This value is
not the DVMRP interface or
tunnel metric, which are shown under
Metric
in other
displays.
Occasionally, instead of a numeric value, you may see
NR
,
meaning “network unreachable.” Your module may have
trouble computing the hop count because of factors such
as an upstream router being temporarily congested. This
condition is usually resolved in a short period of time.
Tmr Amount of time (in seconds) since each entry was last
reset.
Parent The interface that connects to the upstream router
(Gateway). Because DVMRP forms a loopless spanning
tree to reach all hosts for a given IP multicast group, your
module always chooses a single parent interface. Either an
I
or a
T
precedes the index number. An
I
indicates that
the index is an interface index number. A
T
indicates that
the index is a tunnel index number.
Children Interfaces that communicate with downstream routers or
local subnetworks. The module forwards incoming IP
multicast traffic through these interfaces. Either an
I
or a
T
precedes each index number. An
I
precedes an
interface index number. A
T
precedes a tunnel index
number.