Brocade Communications Systems ICX 7250 series, Configuration Manual

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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 holdtime seconds 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 Advertisement message from the Layer 3 switch, the host
resets the hold time for the Layer 3 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.
The maxadvertinterval parameter specifies the maximum amount of time the Layer 3 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.
The minadvertinterval parameter specifies the minimum amount of time the Layer 3 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.
The preference number parameter specifies the IRDP preference level of this Layer 3 switch. If a host receives Router Advertisements
from multiple routers, the host selects the router interface that sent the message with the highest interval as the host default gateway. The
valid range is from 0 to 4294967296. The default is 0.
Configuring UDP broadcast and IP helper parameters
Some applications rely on client requests sent as limited IP broadcasts addressed to the UDP application port. If a server for the
application receives such a broadcast, the server can reply to the client. Routers do not forward subnet directed broadcasts, so the client
and server must be on the same network for the broadcast to reach the server. If the client and server are on different networks (on
opposite sides of a router), the client request cannot reach the server.
You can configure the Layer 3 switch to forward clients‘ requests to UDP application servers. To do so:
• Enable forwarding support for the UDP application port, if forwarding support is not already enabled.
• Configure a helper adders on the interface connected to the clients. Specify the helper address to be the IP address of the
application server or the subnet directed broadcast address for the IP subnet the server is in. A helper address is associated with
a specific interface and applies only to client requests received on that interface. The Layer 3 switch forwards client requests for
any of the application ports the Layer 3 switch is enabled to forward to the helper address.
Forwarding support for the following application ports is enabled by default:
• dns (port 53)
• tftp (port 69)
• time (port 37)
• tacacs (port 65)
NOTE
The application names are the names for these applications that the Layer 3 switch software recognizes, and might not match
the names for these applications on some third-party devices. The numbers listed in parentheses are the UDP port numbers for
the applications. The numbers come from RFC 1340.
Configuring IP parameters - Layer 3 switches
Brocade FastIron Layer 3 Routing Configuration Guide
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