Resetting Ldp Sessions; Managing And Optimizing Mpls Forwarding; Configuring Mpls Mtu - HP 12500 Series Configuration Manual

Resetting LDP sessions

If you change LDP session parameters when some LDP sessions are up, the LDP sessions will not be able
to function normally. In this case, reset LDP sessions so the LDP peers renegotiate parameters and
establish new sessions.
Use the following command to reset LDP sessions:
To do...
Reset LDP sessions

Managing and optimizing MPLS forwarding

Configuring MPLS MTU

An MPLS label stack is inserted between the link layer header and network layer header of a packet.
During MPLS forwarding, a packet, after encapsulated with an MPLS label, may exceed the allowed
length of the link layer and thus cannot be forwarded, although the network layer packet is smaller than
the MTU of the interface.
To address the issue, you can configure the MPLS MTU on an interface of an LSR. Then, the LSR will
compare the length of an MPLS packet against the configured MPLS MTU on the interface. When the
packet is larger than the MPLS MTU:
If fragmentation is allowed, the LSR removes the label stack from the packet, fragments the IP packet
•
(the length of a fragment is the MPLS MTU minus the length of the label stack), adds the label stack
back into each fragment, and then forwards the fragments.
If fragmentation is not allowed, the LSR drops the packet directly.
•
To configure the MPLS MTU of an interface:
To do...
Enter system view
Enter interface view
Configure the MPLS MTU of the
interface
Use the command...
reset mpls ldp [ all | [ vpn-instance
vpn-instance-name ] [ fec mask |
peer peer-id ] ]
Use the command...
system-view
interface interface-type
interface-number
mpls mtu value
20
Remarks
Available in user view
Remarks
—
—
Required
By default, the MPLS MTU of an
interface is not configured.