Example for Configuring LB for a Bidirectional LSP

This section provides an example for configuring loopback (LB) for a bidirectional LSP.

Networking Requirements

On the network shown in Figure 1, a bidirectional LSP is established to connect label switching routers (LSRs) A, B, and C. The following deployment is made to ensure the connectivity between LSRA and LSRC:

LSRA and LSRC serve as MEPs.
LSRB serves as a MIP.

LB can be used on a MEP to check the following items:

Reachability of the RMEP
Round-trip delay in the communication between the MEP and RMEP
Loss of ping packets between the MEP and RMEP

LB counts only the ping packets that are lost after being sent out, providing a rough packet loss ratio of the link between MEPs. The LM function can be used to obtain the accurate packet loss ratio of the link between MEPs.

Figure 1 Bidirectional LSP

Interfaces 1 through 2 in this example are GE 0/1/0 and GE 0/1/8, respectively.

**Table 1** Interfaces and IP addresses
Device	Interface	IP Address
LSRA	Loopback1	1.1.1.1/32
LSRA	GigabitEthernet0/1/0	2.1.1.1/24
LSRB	Loopback1	2.2.2.2/32
	GigabitEthernet0/1/0	2.1.1.2/24
	GigabitEthernet0/1/8	3.2.1.1/24
LSRC	Loopback1	3.3.3.3/32
LSRC	GigabitEthernet0/1/8	3.2.1.2/24

Configuration Roadmap

The configuration roadmap is as follows:

Create an ME instance and bind it to a bidirectional LSP.
Enable LB.

Data Preparation

To complete the configuration, you need the following data:

MEG name
Name of the tunnel interface to which an ME instance is bound

Procedure

Configure a bidirectional LSP.
For configuration details, see "Example for Configuring a Static Bidirectional Co-routed CR-LSP" in HUAWEI NetEngine 8000 F SeriesRouter Configuration Guide - MPLS or "Configuration Files" in this section.

Create an ME instance and bind it to the bidirectional LSP.

# Create an ME instance named test on LSRA and bind it to Tunnel 10.

[~LSRA] mpls-tp meg test
[~LSRA-mpls-tp-meg-test] me te interface Tunnel 10 mep-id 1 remote-mep-id 2
[*LSRA-mpls-tp-meg-test] commit

# Create an ME instance named test on LSRC and bind it to Tunnel 20.

[~LSRC] mpls-tp meg test
[~LSRC-mpls-tp-meg-test] me te interface Tunnel 20 mep-id 2 remote-mep-id 1
[*LSRC-mpls-tp-meg-test] commit

Enable LB.

LB can be used to monitor the connectivity between a MEP and its RMEP or a MIP. In this example, LB is used to monitor the connectivity between LSRA and LSRC.

Enable LB on LSRA.

<LSRA> ping meg test
  PING test: 9 data bytes, press CTRL_C to break
    Reply from test: bytes=9, Sequence=1 time=100 ms
    Reply from test: bytes=9, Sequence=2 time=90 ms
    Reply from test: bytes=9, Sequence=3 time=100 ms
    Reply from test: bytes=9, Sequence=4 time=90 ms
    Reply from test: bytes=9, Sequence=5 time=100 ms
  --- ping statistics ---
    5 packet (s) transmitted
    5 packet (s) received
    0.00% packet loss
    round-trip min/avg/max 90/96/100 ms

Configuration Files

LSRA configuration file

#
 sysname LSRA
#
 mpls lsr-id 1.1.1.1
 mpls
  mpls te
#
 bidirectional static-cr-lsp ingress Tunnel10
  forward nexthop 2.1.1.2 out-label 20
  backward in-label 20
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 2.1.1.1 255.255.255.0
 mpls
 mpls te
#
interface LoopBack1
 ip address 1.1.1.1 255.255.255.255
#
interface Tunnel10
 ip address unnumbered interface LoopBack1
 tunnel-protocol mpls te
 destination 3.3.3.3
 mpls te signal-protocol cr-static
 mpls te tunnel-id 100
 mpls te bidirectional
#
 ip route-static 2.2.2.2 255.255.255.255 2.1.1.2
 ip route-static 3.3.3.3 255.255.255.255 2.1.1.2
#
 mpls-tp meg test
  me te interface Tunnel10 mep-id 1 remote-mep-id 2
#
return

LSRB configuration file

#
 sysname LSRB
#
 mpls lsr-id 2.2.2.2
 mpls
  mpls te
#
 bidirectional static-cr-lsp transit lsp1
  forward in-label 20 nexthop 3.2.1.2 out-label 40
  backward in-label 16 nexthop 2.1.1.1 out-label 20
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 2.1.1.2 255.255.255.0
 mpls
 mpls te
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 3.2.1.1 255.255.255.0
 mpls
 mpls te
#
interface LoopBack1
 ip address 2.2.2.2 255.255.255.255
#
 ip route-static 1.1.1.1 255.255.255.255 2.1.1.1
 ip route-static 3.3.3.3 255.255.255.255 3.2.1.2
#
return

LSRC configuration file

#
 sysname LSRC
#
 mpls lsr-id 3.3.3.3
 mpls
  mpls te
#
 bidirectional static-cr-lsp egress lsp1
  forward in-label 40 lsrid 1.1.1.1 tunnel-id 100
  backward nexthop 3.2.1.1 out-label 16
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 3.2.1.2 255.255.255.0
 mpls
 mpls te
#
interface LoopBack1
 ip address 3.3.3.3 255.255.255.255
#
interface Tunnel20
 ip address unnumbered interface LoopBack1
 tunnel-protocol mpls te
 destination 1.1.1.1
 mpls te signal-protocol cr-static
 mpls te tunnel-id 200
 mpls te passive-tunnel
 mpls te binding bidirectional static-cr-lsp egress lsp1 
#
 ip route-static 1.1.1.1 255.255.255.255 3.2.1.1
 ip route-static 2.2.2.2 255.255.255.255 3.2.1.1
#
 mpls-tp meg test
  me te interface Tunnel20 mep-id 2 remote-mep-id 1
#
return