Configuring Php - 3Com S7906E Configuration Manual

An MPLS LSR ID is in the format of an IP address and must be unique within an MPLS domain.
You are recommended to use the IP address of a loopback interface on an LSR as the MPLS LSR
ID.
At present, the S7900E series switches support enabling MPLS on only VLAN interfaces.
As MPLS will encapsulate original packets with single layer or multiple layers of labels, after
enabling MPLS on the VLAN interface of a VLAN, you are recommended to enable the jumboframe
function on the ports of the VLAN and configure a proper jumbo frame length to prevent packets
from being dropped due to size limit. For example, if two layers of MPLS labels are required for
encapsulating FTP packets, you need to configure the jumbo frame length on related ports to 1544
bytes: 1518 bytes for the FTP packet + 4 bytes × 2 for the MPLS labels + 4 bytes for the VLAN tag
+ 14 bytes for the Ethernet frame header. For descriptions of the jumboframe function, refer to
Ethernet Port Configuration in the Access Volume.

Configuring PHP

Configure PHP on an egress and select the type of labels for the egress to distribute based on whether
the penultimate hop supports PHP.
Configuration Prerequisites
Before configuring PHP, be sure to complete the following task:
Configuring MPLS basic capability on all LSRs.
Configuration Procedure
According to RFC 3032 "MPLS Label Stack Encoding":
A label value of 0 represents an IPv4 explicit null label and is valid only when it appears at the
bottom of a label stack.
A label value of 3 represents an implicit null label and never appears in the label stack. When an
LSR finds that it is assigned an implicit null label, it directly performs a pop operation, rather than
substitutes the implicit null label for the original label at the stack top.
Follow these steps to configure PHP:
To do...
Enter system view
Enter MPLS view
Use the command...
system-view
mpls
1-18
Remarks
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