HP 3500YL - Manual (Page 195)

IP Routing Features
Configuring IP Parameters for Routing Switches
Configuring Forwarding Parameters
The following configurable parameters control the forwarding behavior of
ProCurve routing switches:
■ Time-To-Live (TTL) threshold
■ Forwarding of directed broadcasts
All these parameters are global and thus affect all IP interfaces configured on
the routing switch.
To configure these parameters, use the procedures in the following sections.
Changing the TTL Threshold
The configuration of this parameter is covered in the chapter titled, “Config­
uring IP Addressing” in the Management and Configuration Guide for your
routing switch.
Enabling Forwarding of Directed Broadcasts
A directed broadcast is an IP broadcast to all devices within a single directly-
attached network or subnet. A net-directed broadcast goes to all devices on a
given network. A subnet-directed broadcast goes to all devices within a given
subnet.
N o t e A less common type, the all-subnets broadcast, goes to all directly-attached
subnets. Forwarding for this broadcast type also is supported, but most
networks use IP multicasting instead of all-subnet 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:
ProCurve(config)# ip directed-broadcast
Syntax: [no] ip directed-broadcast
ProCurve software makes the forwarding decision based on the routing
switch's knowledge of the destination network prefix. Routers cannot deter­
mine that a message is unicast or directed broadcast apart from the destina­
tion network prefix. The decision to forward or not forward the message is by
definition only possible in the last-hop router.
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