Setting Mpls Mtu - HP FlexNetwork 10500 Series Configuration Manual

Step
1. Enter system view.
2. Configure an LSR ID for the
local node.
3. Enter the view of the interface
that needs to perform MPLS
forwarding.
4. Enable MPLS on the
interface.

Setting MPLS MTU

MPLS adds the label stack between the link layer header and network layer header of each packet.
To make sure the size of MPLS labeled packets is smaller than the MTU of an interface, configure an
MPLS MTU on the interface.
MPLS compares each MPLS packet against the interface MPLS MTU. When the packet exceeds the
MPLS MTU:
•
If fragmentation is allowed, MPLS performs the following operations:
a. Removes the label stack from the packet.
b. Fragments the IP packet. The length of a fragment is the MPLS MTU minus the length of the
label stack.
c. Adds the label stack to each fragment, and forwards the fragments.
•
If fragmentation is not allowed, the LSR directly forwards the packet.
To set an MPLS MTU for an interface:
Step
1. Enter system view.
2. Enter interface view.
3. Set an MPLS MTU for the
interface.
The following applies when an interface handles MPLS packets:
•
MPLS packets carrying L2VPN or IPv6 packets are always forwarded by an interface, even if
the length of the MPLS packets exceeds the MPLS MTU of the interface. Whether the
forwarding can succeed depends on the actual forwarding capacity of the interface.
•
If the MPLS MTU of an interface is greater than the MTU of the interface, data forwarding might
fail on the interface.
Command
system-view
mpls lsr-id lsr-id
interface interface-type
interface-number
mpls enable
Command
system-view
interface interface-type
interface-number
mpls mtu size
7
Remarks
N/A
By default, no LSR ID is
configured.
An LSR ID must be unique in an
MPLS network and in IP address
format. As a best practice, use
the IP address of a loopback
interface as an LSR ID.
N/A
By default, MPLS is disabled on
the interface.
You cannot enable MPLS on the
egress interface of an IP tunnel
source because an LSP cannot
forward packets encapsulated
by an IP tunnel.
Remarks
N/A
N/A
By default, no MPLS MTU is set
on an interface.