Managed Switch CLI Manual, Release 8.0
Routing Commands
4-12
v1.0, July 2009
no ip netdirbcast
This command disables the forwarding of network-directed broadcasts. When disabled, network
directed broadcasts are dropped.
ip mtu
This command sets the IP Maximum Transmission Unit (MTU) on a routing interface. The IP
MTU is the size of the largest IP packet that can be transmitted on the interface without
fragmentation. The software currently does not fragment IP packets.
•
Packets forwarded in hardware ignore the IP MTU.
•
Packets forwarded in software are dropped if they exceed the IP MTU of the outgoing
interface.
Packets originated on the router, such as OSPF packets, may be fragmented by the IP stack. The IP
stack uses its default IP MTU and ignores the value set using the ip mtu command.
OSPF advertises the IP MTU in the Database Description packets it sends to its neighbors during
database exchange. If two OSPF neighbors advertise different IP MTUs, they will not form an
adjacency. (unless OSPF has been instructed to ignore differences in IP MTU with the
ip ospf
mtu-ignore
command.)
Format
ip netdirbcast
Mode
Interface Config
Format
no ip netdirbcast
Mode
Interface Config
Note:
The IP MTU size refers to the maximum size of the IP packet (IP IP
payload). It does not include any extra bytes that may be required for Layer-2
headers. To receive and process packets, the Ethernet MTU (see
“mtu” on page 3-
5
) must take into account the size of the Ethernet header.
Default
1500 bytes
Format
ip mtu <68-1500>
Mode
Interface Config
Summary of Contents for FSM726v3 - ProSafe Fast Ethernet L2 Managed Switch
Page 4: ...v1 0 July 2009 iv...
