IP Routing Features 
Configuring IRDP 
messages from other routers at the same time. The interval on each IRDP-
enabled routing switch interface is independent of the interval on other 
IRDP-enabled interfaces. The default maximum message interval is 600 
seconds. The default minimum message interval is 450 seconds. 
■  Preference - If a host receives multiple Router Advertisement messages 
from different routers, the host selects the router that send the message 
with the highest preference as the default gateway. The preference can be 
a number from -4294967296 to 4294967295. The default is 0. 
Enabling IRDP Globally 
To enable IRDP globally, enter the following command: 
HP(config)# ip irdp 
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 param-
eters, enter commands such as the following: 
HP(config)# vlan 1 
HP(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 - This parameter 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 multi-
cast packets addressed to IP multicast group 224.0.0.1. This is the 
default. 
■  holdtime < seconds > - This parameter 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 Adver-
tisement message from the routing switch, the host resets the hold time 
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