Broadcast Tasks; Fragmentation - Juniper IGP - CONFIGURATION GUIDE V11.1.X Configuration Manual

JUNOSe 11.0.x IP, IPv6, and IGP Configuration Guide
The best solution to the broadcast storm is to use a single broadcast address scheme
on a network. Most IP implementations allow the network manager to set the address
to be used as the broadcast address. Many implementations of IP, including the one
on your router, can accept and interpret all possible forms of broadcast addresses.

Broadcast Tasks

You can use two broadcast-related IP commands to perform broadcast-related tasks.
ip broadcast-address
ip directed-broadcast

Fragmentation

Fragmentation is the process of segmenting a large IP datagram into several smaller
pieces. Fragmentation is required when IP must transmit a large packet through a
network that transmits smaller packets, or when the MTU size of the other network
is smaller.
By default, the router does not fragment the packet if the don't-fragment bit (DF bit)
is set in the IP header. You can specify that the router not consider the DF bit before
determining whether to fragment a packet.
NOTE: Lower-layer protocols can also set the MTU value. If MTU values set in lower
layers differ from the one set at the IP layer, the router always uses the MTU
lower-layer value.
ip ignore-df-bit
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Fragmentation
Use to broadcast to all addresses in the host portion of an IP address.
You specify an IP address to set the broadcast address.
Example
host1(config-if)#ip broadcast-address 255.255.255.255
Use the no version to restore the default IP broadcast address.
See ip broadcast-address
Use to enable translation of directed broadcasts to physical broadcasts.
Example
host1(config-if)#ip directed-broadcast
Use the no version to disable the function.
See ip directed-broadcast