1326 CHAPTER 76: MPLS B ASICS CONFIGURATIONn Currently, these types of interfaces support MPLS capability: serial interface, asyncinterface, Layer 3 Ethernet interface (Ethernet interface, GE interface, and XGEinterface), ATM interface, POS interface, Layer 3 virtual Ethernet interface (that is,virtual-Ethernet interface), virtual template, Mp-group interface, MFR interface,tunnel interface, and VLAN interface.ConfigurationPrerequisitesBefore configuring MPLS basic capability, be sure to complete these tasks:■ Configuring physical parameters on related interfaces■ Configuring link layer attributes on related interfaces■ Configuring IP addresses for related interfaces■ Configuring static routes or an IGP protocol, ensuring that LSRs can reach eachothern MPLS basic capability can be configured on LSRs even when LSRs cannot reacheach other. However, you must configure the mpls ldp transport-addresscommand in this case. For details of the command, refer to “MPLS BasicsConfiguration” on page 1311.Configuration Procedure Follow these steps to configure MPLS basic capability:n An LSR ID uses the format of an IP address and is unique within an MPLS domain.You are recommended to use the IP address of a loopback interface on an LSR asthe LSR ID.Configuring PHP You configure PHP on the egress and select the type of labels for the egress todistribute based on whether the penultimate hop supports PHP.ConfigurationPrerequisitesBefore configuring PHP, be sure to complete the following task:■ Configuring MPLS basic capability on all LSRsConfiguration 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 itappears at the bottom of the label stack. It indicates that the label of theTo do... Use the command... RemarksEnter system view system-view -Configure the MPLS LSR ID mpls lsr-id lsr-id RequiredBy default, no LSR ID isconfigured.Enable MPLS for the currentnode and enter MPLS viewmpls RequiredNot enabled by defaultExit to system view quit -Enter interface view interface interface-typeinterface-number-Enable MPLS for the interface mpls RequiredNot enabled by default
