This command enables IRDP on the IP interfaces on all ports. Each port uses the default values for the IRDP
parameters.
Enabling IRDP on an individual VLAN interface
To enable IRDP on an individual VLAN interface and configure IRDP parameters, enter commands such as the
following:
switch(config)# vlan 1
switch(vlan-1)# ip irdp maxadvertinterval 400
This example shows how to enable IRDP on a specific interface (VLAN 1) and change the maximum
advertisement interval for Router Advertisement messages to 400 seconds.
Syntax:
[no] ip irdp [broadcast | multicast] [holdtime
seconds
] [maxadvertinterval
seconds
] [minadvertinterval
seconds
] [preference
number
]
broadcast | multicast
Specifies the packet type the routing switch uses to send the Router Advertisement:
broadcast
The routing switch sends Router Advertisements as IP broadcasts.
multicast
The routing switch sends Router Advertisements as multicast packets addressed to IP multicast group
224.0.0.1. This is the default.
holdtime seconds
Specifies how long a host that receives a Router Advertisement from the routing switch should consider the
advertisement to be valid.
When a host receives a new Router Advertisement message from the routing switch, the host resets the hold
time for the routing switch to the hold time specified in the new advertisement. If the hold time of an
advertisement expires, the host discards the advertisement, concluding that the router interface that sent the
advertisement is no longer available. The value must be greater than the value of the maxadvertinterval
parameter and cannot be greater than 9000.
The default is three times the value of the maxadvertinterval parameter.
maxadvertinterval
Specifies the maximum amount of time the routing switch waits between sending Router Advertisements. You
can specify a value from 1 to the current value of the holdtime parameter. The default is 600 seconds.
minadvertinterval
Specifies the minimum amount of time the routing switch can wait between sending Router Advertisements.
The default is three-fourths (0.75) the value of the maxadvertinterval parameter.
If you change the maxadvertinterval parameter, the software automatically adjusts the minadvertinterval
parameter to be three-fourths the new value of the maxadvertinterval parameter. If you want to override the
automatically configured value, you can specify an interval from 1 to the current value of the
maxadvertinterval parameter
preference number
Specifies the IRDP preference level of this routing switch. If a host receives Router Advertisements from
multiple routers, the host selects the router interface that sent the message with the highest preference as the
host's default gateway. The valid range is -4294967296 to 4294967295. The default is 0.
Chapter 13 ICMP Router Discovery Protocol
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