Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 78)

• Packet type - The Layer 3 switch can send Router Advertisement messages as IP broadcasts or as
IP multicasts addressed to IP multicast group 224.0.0.1. The packet type is IP broadcast.
• Maximum message interval and minimum message interval - When IRDP is enabled, the Layer
3 switch sends the Router Advertisement messages every 450 - 600 seconds by default. The time
within this interval that the Layer 3 switch selects is random for each message and is not affected
by traffic loads or other network factors. The random interval minimizes the probability that a host
will receive Router Advertisement messages from other routers at the same time. The interval on
each IRDP-enabled Layer 3 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.
• Hold time - Each Router Advertisement message contains a hold time value. This value specifies
the maximum amount of time the host should consider an advertisement to be valid until a newer
advertisement arrives. When a new advertisement arrives, the hold time is reset. The hold time is
always longer than the maximum advertisement interval. Therefore, if the hold time for an
advertisement expires, the host can reasonably conclude that the router interface that sent the
advertisement is no longer available. The default hold time is three times the maximum message
interval.
• Preference - If a host receives multiple Router Advertisement messages from different routers, the
host selects the router that sent the message with the highest preference as the default gateway.
The preference can be a number from 0-4294967296. The default is 0.
Enabling IRDP globally
To globally enable IRDP, enter the following command.
device(config)# ip irdp
This command enables IRDP on the IP interfaces on all ports. Each port uses the default values for
the IRDP parameters. The parameters are not configurable when IRDP is globally enabled.
Enabling IRDP on an individual port
To enable IRDP on an individual interface and change IRDP parameters, enter commands such as the
following.
device(config)# interface ethernet 1/3
device(config-if-1/3)# ip irdp maxadvertinterval 400
This example shows how to enable IRDP on a specific port and change the maximum advertisement
interval for Router Advertisement messages to 400 seconds.
NOTE
To enable IRDP on individual ports, you must leave the feature globally disabled.
Syntax: [no] ip irdp { broadcast | multicast } [ holdtime seconds ] [ maxadvertinterval seconds ] [
minadvertinterval seconds ] [ preference number ]
The broadcast and multicast parameters specify the packet type the Layer 3 switch uses to send
Router Advertisement:
• broadcast - The Layer 3 switch sends Router Advertisement as IP broadcasts. This is the default.
• multicast - The Layer 3 switch sends Router Advertisement as multicast packets addressed to IP
multicast group 224.0.0.1.
The holdtimeseconds parameter specifies how long a host that receives a Router Advertisement from
the Layer 3 switch should consider the advertisement to be valid. When a host receives a new Router
Enabling IRDP globally
78 FastIron Ethernet Switch Layer 3 Routing Configuration Guide
53-1003087-04