HP MSR2000/3000/4000 Router Series Layer 3 - IP Services Command Reference

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Predefined user roles
network-admin
Parameters
vpn-instance vpn-instance-name: Specifies the VPN instance to which the specified address belongs. The
vpn-instance-name argument is a case-sensitive string of 1 to 31 characters. The specified VPN instance
must exist. If the specified IP address is on the public network, do not use this option.
ip-address: Specifies an IP address.
Usage guidelines
It is a good practice to specify the IP address of the loopback interface as the source IP address for
outgoing ping echo request and ICMP error messages. This feature helps users to locate the sending
device easily.
Examples
# Specify 1.1.1.1 as the source address for outgoing ICMP packets.
<Sysname> system-view
[Sysname] ip icmp source 1.1.1.1
ip mtu
Use ip mtu to configure an MTU for an interface.
Use undo ip mtu to restore the default.
Syntax
ip mtu mtu-size
undo ip mtu
Default
No MTU is configured for an interface.
Views
Interface view
Predefined user roles
network-admin
Parameters
mtu-size: Specifies an MTU in the range of 128 to 1560 bytes.
Usage guidelines
When a packet exceeds the MTU of the output interface, the device processes it in one of the following
ways:
• If the packet disallows fragmentation, the device discards it.
• If the packet allows fragmentation, the device fragments it and forwards the fragments.
Fragmentation and reassembling consume system resources, so set an appropriate MTU for an interface
to avoid fragmentation.
If an interface supports both the mtu and ip mtu commands, the device fragments a packet based on the
MTU set by the ip mtu command.