Configuring Forwarding Parameters - HP Procurve 2650 Management And Configuration Manual

IP Routing Features
Configuring IP Parameters for Routing Switches
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Configuring Forwarding Parameters

The following configurable parameters control the forwarding behavior of
your routing switch:
I Time-To-Live (TTL) threshold — configuring this parameter is covered in
chapter 7, "Configuring IP Addressing".
Forwarding of directed broadcasts — see below.
I
These parameters are global and thus affect all IP interfaces configured on the
routing switch.
Enabling Forwarding of Directed Broadcasts
A directed broadcast is an IP broadcast to all devices within a single directly-
attached network or sub-net. A net-directed broadcast goes to all devices on
a given network. A sub-net-directed broadcast goes to all devices within a
given sub-net.
A less common type, the all-sub-nets broadcast, goes to all directly-attached
sub-nets. Forwarding for this broadcast type also is supported, but most
networks use IP multicasting instead of all-sub-net broadcasting.
Forwarding for all types of IP directed broadcasts is disabled by default. You
can enable forwarding for all types if needed. You cannot enable forwarding
for specific broadcast types.
To enable forwarding of IP directed broadcasts, enter the following CLI
command:
HPswitch(config)# ip directed-broadcast
Syntax: [no] ip directed-broadcast
HP software makes the forwarding decision based on the routing switch's
knowledge of the destination network prefix. Routers cannot determine that
a message is unicast or directed broadcast apart from the destination network
prefix. The decision to forward or not forward the message is by definition
only possible in the last hop router.
To disable the directed broadcasts, enter the following CLI command:
HPswitch(config)# no ip directed-broadcast