Multicast and Routing Guide K/KA/KB.15.15

Up time (sec) The elapsed time in seconds since the router
learned the information for the current
instance of the indicated multicast flow. Note
that on an Originator router when a
forwarding flow moves to a non-forwarding
state (i.e. when pruned) the Up time value
for that flow is reset to 0.
Expire Time (sec) An mroute which is in a forwarding state —
one which represents an active, connected
flow for which there are downstream routers
and/or locally connected hosts interested in
the flow — does not expire. When other
PIM-SM routers or locally connected hosts
are no longer interested in an active flow,
the related mroute on a DR moves to a
blocking state, and an mroute in this state
does not expire either. In both cases the
mroute is only removed from the system
when it is no longer needed and so the
displayed value for expire time in these
situations is not meaningful.
For an mroute on a DR router whose flow is
no longer active — including mroutes on
non-DR routers whose flow has been pruned
— expire time indicates when the mroute
entry will eventually be cleared.
Note that flows that are registered with an
RP router but are not connected downstream
(one for which there is no entry displayed in
the neighbor field on the RP) will also have
an mroute entry that does not expire.
Multicast routing protocol Identifies the IP multicast routing protocol
through which the current flow was learned.
Unicast routing protocol Identifies the IP routing protocol through
which the router learned the upstream
interface for the current multicast flow. The
listed protocol will be one of connected,
static, rip, ospf or other.
Metric Indicates the path cost upstream to the multicast source. Used when
multiple multicast routers contend to determine the best path to the
multicast source. The lower the value, the better the path.
Metric pref Used when multiple multicast routers contend to determine the
path to the multicast source. When this value differs between
routers, PIM selects the router with the lowest value. If Metric
pref is the same between contending multicast routers, then PIM
selects the router with the lowest metric value to provide the path
for the specified multicast traffic. (Different vendors assign
differing values for this setting.)
Assert timer The time remaining until the router ceases to wait for a response
from another multicast router to negotiate the best path back
to the multicast source. If this timer expires without a response
from any contending multicast routers, then the router assumes
82 PIM-SM (Sparse Mode)