Specifications

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Catalyst 4500 Se ries S wit ch C is co IO S C om mand R efer ence —Re lease I OS XE 3 .3.0 XO(1 5.1 (1)XO)
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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
show ip mfib
show ip mfib
To display all active Multicast Forwarding Information Base (MFIB) routes, use the show ip mfib
command .
show ip mfib [all | counter s | log [n]]
Syntax Description
Defaults This command has no default settings.
Command Modes Privileged EXEC mode
Usage Guidelines The MFIB table contains a set of IP multicast routes; each route in the MFIB table contains several flags
that associate to the route.
The route flags indicate how a packet that matches a route is forwarded. For example, the IC flag on an
MFIB route indicates that some process on the switch needs to receive a copy of the packet. These flags
are associated with MFIB routes:
• Internal Copy (IC) fla g—Set on a route when a proces s on the switch n eeds to receive a copy o f all
packets matching the specified rout e.
• Signaling (S) flag—Set on a r oute whe n a s witch proc ess nee ds notific ation that a pa cket matc hing
the route is received. In the expected b ehavior, the protocol c ode upd ates the MFIB st ate in r esponse
to having received a packet on a signaling inte rface.
• Connected (C) fla g—When se t on a route , the C flag has the same me aning as the S flag, e xcept tha t
the C flag indicates that onl y packets sent by dire ctly connec ted hosts to the route sho uld be signa led
to a protocol process.
A route can also have a set of flags associated with one or more interfaces. For an (S,G) route, the flags
on interface 1 indicate how the ingre ss packets s hould be tr eated and w hether pa ckets matc hing the route
should be forwarded onto interfac e 1. These per-interface f lags are associated with t he MFIB routes:
• Accepting (A)—Set on the RPF interface when a packet that arrives on the interface and that is
marked as Accepting (A) is forwarded to all Forwarding (F) interfaces.
• Forwarding (F)—Us ed with th e A flag as d escribed above. The set of forwar ding inter faces togethe r
form a multicast olist or output interface list.
• Signaling (S)—Set on an interface when a multicast routing protocol process in Cisco I OS needs to
be notified of ingress packets on that interface.
all (Optional) Specifies all routes in the MFIB, including those routes that are used to
accelerate fast switching but that are not necessarily in the upper-layer routing protocol
table.
counter s (Optional) Specifies the counts of MFIB-related events. Only nonzero counters are
shown.
log (Optional) Specifies a log of the most recent number of MFIB-related events. The most
recent event is first.
n (Optional) Number of events.