Enabling Irdp Globally - Dell PowerConnect B-RX Configuration Manual

Some types of hosts use the Router Solicitation messages to discover their default gateway. When
IRDP is enabled, the device responds to the Router Solicitation messages. Some clients interpret
this response to mean that the device is the default gateway. If another router is actually the
default gateway for these clients, leave IRDP disabled on the device.
IRDP uses the following parameters. If you enable IRDP on individual ports rather than globally,
you can configure these parameters on an individual port basis using:
•
•
•
•

Enabling IRDP globally

To globally enable IRDP, enter the following command.
BigIron RX(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.
BigIron RX(config)# interface ethernet 1/3
BigIron RX(config-if-e10000-1/3)# 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.
BigIron RX Series Configuration Guide
53-1001810-01
Packet type – The device 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
device sends the Router Advertisement messages every 450 – 600 seconds by default. The
time within this interval that the device 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 device 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 4294967296 to 4294967295. The
default is 0.
Configuring forwarding parameters
7
207