Example for Configuring SRLG Based on CR-LSP Hot Standby

Networking Requirements

As shown in Figure 1, An MPLS TE tunnel is set up between LSRA and LSRC, with the path LSRA -> LSRB -> LSRC.

The link LSRA -> LSRB and the link LSRA -> LSRE are in the same SRLG (SRLG1 for example); the link LSRC -> LSRB and the link LSRC -> LSRE are in the same SLRG (SRLG2 for example).

To improve reliability, a hot-standby CR-LSP needs to be established and the links of the bypass CR-LSP and primary tunnel must be in different SRLGs.

In this scenario, to avoid loops, ensure that all connected interfaces have STP disabled and connected interfaces are removed from VLAN 1. If STP is enabled and VLANIF interfaces of switches are used to construct a Layer 3 ring network, an interface on the network will be blocked. As a result, Layer 3 services on the network cannot run normally.

Figure 1 Networking for configuring SRLG based on CR-LSP hot standby

Configuration Roadmap

The configuration roadmap is as follows:

Assign an IP address to each interface and configure OSPF to ensure that there are reachable routes between LSRs.
Configure an ID for each LSR and globally enable MPLS, MPLS TE, RSVP-TE, CSPF on each node and interface, and enable OSPF TE.
On the ingress node of the primary tunnel, create a tunnel interface, and specify the IP address, tunneling protocol, destination IP address, tunnel ID, and dynamic signaling protocol RSVP-TE for the tunnel interface. The explicit path is LSRA -> LSRB -> LSRC.
Configure SRLG numbers for SRLG member interfaces.
Configure the SRLG path calculation mode on the ingress node of the primary tunnel.
Configure a hot-standby CR-LSP on the ingress node of the primary tunnel.

Procedure

Assign an IP address to each interface and configure OSPF.

# Configure LSRA. Configure IP addresses for interfaces of LSRB, LSRC, LSRE, and LSRF according to Figure 1. The configurations of LSRB, LSRC, LSRE, and LSRF are similar to the configuration of LSRA, and are not mentioned here.

<HUAWEI> system-view
[HUAWEI] sysname LSRA
[LSRA] vlan batch 100 400 600
[LSRA] interface vlanif 100
[LSRA-Vlanif100] ip address 172.1.1.1 255.255.255.0
[LSRA-Vlanif100] quit
[LSRA] interface vlanif 400
[LSRA-Vlanif400] ip address 172.4.1.1 255.255.255.0
[LSRA-Vlanif400] quit
[LSRA] interface vlanif 600
[LSRA-Vlanif600] ip address 172.6.1.1 255.255.255.0
[LSRA-Vlanif600] quit
[LSRA] interface gigabitethernet 0/0/1
[LSRA-GigabitEthernet0/0/1] port link-type trunk
[LSRA-GigabitEthernet0/0/1] port trunk allow-pass vlan 100
[LSRA-GigabitEthernet0/0/1] quit
[LSRA] interface gigabitethernet 0/0/2
[LSRA-GigabitEthernet0/0/2] port link-type trunk
[LSRA-GigabitEthernet0/0/2] port trunk allow-pass vlan 600
[LSRA-GigabitEthernet0/0/2] quit
[LSRA] interface gigabitethernet 0/0/3
[LSRA-GigabitEthernet0/0/3] port link-type trunk
[LSRA-GigabitEthernet0/0/3] port trunk allow-pass vlan 400
[LSRA-GigabitEthernet0/0/3] quit
[LSRA] interface loopback 1
[LSRA-LoopBack1] ip address 1.1.1.9 255.255.255.255
[LSRA-LoopBack1] quit
[LSRA] ospf 1
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] network 1.1.1.9 0.0.0.0
[LSRA-ospf-1-area-0.0.0.0] network 172.1.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] network 172.4.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] network 172.6.1.0 0.0.0.255
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit

After the configurations are complete, run the display ip routing-table command on each LSR. You can see that the LSRs learn the routes to Loopback1 of each other. The display on LSRA is used as an example.

[LSRA] display ip routing-table
Route Flags: R - relay, D - download to fib, T - to vpn-instance                                     
------------------------------------------------------------------------------  
Routing Tables: Public                                                          
         Destinations : 16       Routes : 18                                    
                                                                                
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface      
                                                                                
        1.1.1.9/32  Direct  0    0           D   127.0.0.1       LoopBack1      
        2.2.2.9/32  OSPF    10   1           D   172.1.1.2       Vlanif100
        3.3.3.9/32  OSPF    10   2           D   172.1.1.2       Vlanif100
                    OSPF    10   2           D   172.4.1.2       Vlanif400
                    OSPF    10   2           D   172.6.1.2       Vlanif600
        5.5.5.9/32  OSPF    10   1           D   172.4.1.2       Vlanif400
        6.6.6.9/32  OSPF    10   1           D   172.6.1.2       Vlanif600
      127.0.0.0/8   Direct  0    0           D   127.0.0.1       InLoopBack0    
      127.0.0.1/32  Direct  0    0           D   127.0.0.1       InLoopBack0    
      172.1.1.0/24  Direct  0    0           D   172.1.1.1       Vlanif100
      172.1.1.1/32  Direct  0    0           D   127.0.0.1       Vlanif100
      172.2.1.0/24  OSPF    10   2           D   172.1.1.2       Vlanif100
      172.4.1.0/24  Direct  0    0           D   172.4.1.1       Vlanif400
      172.4.1.1/32  Direct  0    0           D   127.0.0.1       Vlanif400
      172.5.1.0/24  OSPF    10   2           D   172.4.1.2       Vlanif400
      172.6.1.0/24  Direct  0    0           D   172.6.1.1       Vlanif600
      172.6.1.1/32  Direct  0    0           D   127.0.0.1       Vlanif600
      172.7.1.0/24  OSPF    10   2           D   172.6.1.2       Vlanif600

Configure basic MPLS functions and enable MPLS TE, RSVP-TE, and CSPF.

# Configure LSRA. The configurations of LSRB, LSRC, LSRE, and LSRF are similar to the configuration of LSRA, and are not mentioned here. CSPF only needs to be configured on the ingress node of the primary tunnel.

[LSRA] mpls lsr-id 1.1.1.9
[LSRA] mpls
[LSRA-mpls] mpls te
[LSRA-mpls] mpls rsvp-te
[LSRA-mpls] mpls te cspf
[LSRA-mpls] quit
[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls
[LSRA-Vlanif100] mpls te
[LSRA-Vlanif100] mpls rsvp-te
[LSRA-Vlanif100] quit
[LSRA] interface vlanif 400
[LSRA-Vlanif400] mpls
[LSRA-Vlanif400] mpls te
[LSRA-Vlanif400] mpls rsvp-te
[LSRA-Vlanif400] quit
[LSRA] interface vlanif 600
[LSRA-Vlanif600] mpls
[LSRA-Vlanif600] mpls te
[LSRA-Vlanif600] mpls rsvp-te
[LSRA-Vlanif600] quit

Configure OSPF TE.

# Configure LSRA. The configurations of LSRB, LSRC, LSRE, and LSRF are similar to the configuration of LSRA, and are not mentioned here.

[LSRA] ospf
[LSRA-ospf-1] opaque-capability enable
[LSRA-ospf-1] area 0
[LSRA-ospf-1-area-0.0.0.0] mpls-te enable
[LSRA-ospf-1-area-0.0.0.0] quit
[LSRA-ospf-1] quit

On LSRA, create an MPLS TE tunnel for the primary CR-LSP.

# Configure the explicit path of the primary CR-LSP.

[LSRA] explicit-path pri-path
[LSRA-explicit-path-pri-path] next hop 172.1.1.2
[LSRA-explicit-path-pri-path] next hop 172.2.1.2
[LSRA-explicit-path-pri-path] next hop 3.3.3.9
[LSRA-explicit-path-pri-path] quit

# Configure the MPLS TE tunnel interface of the primary CR-LSP.

[LSRA] interface tunnel 1
[LSRA-Tunnel1] ip address unnumbered interface loopBack 1
[LSRA-Tunnel1] tunnel-protocol mpls te
[LSRA-Tunnel1] destination 3.3.3.9
[LSRA-Tunnel1] mpls te tunnel-id 100
[LSRA-Tunnel1] mpls te path explicit-path pri-path
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit

Run the display interface tunnel 1 command on LSRA. You can see that the tunnel status is Up.

[LSRA] display interface tunnel 1
Tunnel1 current state : UP                                                  
Line protocol current state : UP                                                
Last line protocol up time : 2013-01-22 16:57:00                                
Description:
...

Configure SRLG.

Configure SRLG1 for links LSRA -> LSRB and LSRA -> LSRE, and SRLG2 for links LSRC -> LSRB and LSRC -> LSRE. Configure the SRLG path calculation mode on the ingress node LSRA of the primary tunnel.

# Configure LSRA.

[LSRA] interface vlanif 100
[LSRA-Vlanif100] mpls te srlg 1
[LSRA-Vlanif100] quit
[LSRA] interface vlanif 400
[LSRA-Vlanif400] mpls te srlg 1
[LSRA-Vlanif400] quit

# Configure LSRB.

[LSRB] interface vlanif 200
[LSRB-Vlanif200] mpls te srlg 2
[LSRB-Vlanif200] quit

# Configure LSRE.

[LSRE] interface vlanif 500
[LSRE-Vlanif500] mpls te srlg 2
[LSRE-Vlanif500] quit

# Configure the SRLG path calculation mode on LSRA.

[LSRA] mpls
[LSRA-mpls] mpls te srlg path-calculation strict
[LSRA-mpls] quit

Run the display mpls te srlg all command to view SRLG information and the interfaces that belong to the SRLG. The display on LSRA is used as an example.

[LSRA] display mpls te srlg all
Total SRLG supported : 1024     
Total SRLG configured : 2                                                       
SRLG    1:           Vlanif100             Vlanif400

Run the display mpls te link-administration srlg-information to view SRLGs to which the interfaces belong. The display on LSRA is used as an example.

[LSRA] display mpls te link-administration srlg-information
                                                                               
 SRLGs on Vlanif100 :                                                
              1                                                                 
                                                                                
 SRLGs on Vlanif400 :                                                
              1

Run the display mpls te cspf tedb srlg command to view TEDB information of the specified SRLG.

[LSRA] display mpls te cspf tedb srlg 1
Interface-Address   IGP-Type            Area                                    
172.1.1.1           OSPF                0                                       
172.4.1.1           OSPF                0

[LSRA] display mpls te cspf tedb srlg 2
Interface-Address   IGP-Type            Area                                    
172.2.1.1           OSPF                0                                       
172.5.1.1           OSPF                0

Configure a hot-standby CR-LSP on the ingress node.

# Configure LSRA.

[LSRA] interface tunnel 1
[LSRA-Tunnel1] mpls te backup hot-standby
[LSRA-Tunnel1] mpls te commit
[LSRA-Tunnel1] quit

Run the display mpls te tunnel-interface command on LSRA. You can see that the hot-standby CR-LSP has been established.

[LSRA] display mpls te tunnel-interface
    ----------------------------------------------------------------            
                               Tunnel1                                      
    ----------------------------------------------------------------            
    Tunnel State Desc   :  UP                                                   
    Active LSP          :  Primary LSP                                          
    Session ID          :  100                                                  
    Ingress LSR ID      :  1.1.1.9          Egress LSR ID:  3.3.3.9             
    Admin State         :  UP               Oper State   :  UP                  
    Primary LSP State      : UP                                                 
      Main LSP State       : READY               LSP ID  : 54                   
    Hot-Standby LSP State  : UP                                                 
      Main LSP State       : READY               LSP ID  : 32780

Run the display mpls te hot-standby state interface tunnel 1 command on LSRA to view the hot-standby CR-LSP.

[LSRA] display mpls te hot-standby state interface tunnel 1
(s): same path
---------------------------------------------------------------------           
Verbose information about the Tunnel1 hot-standby state                     
---------------------------------------------------------------------           
session id                               : 100                                  
main LSP token                           : 0x51                                 
hot-standby LSP token                    : 0x4f                                 
HSB switch result                        : Primary LSP                          
HSB switch reason                        : -                                    
WTR config time                          : 10s                                  
WTR remain time                          : -                                    
using overlapped path                    : no

Verify the configuration.

After the configurations are complete, run the display mpls te tunnel path command on LSRA to view nodes that the primary CR-LSP and backup CR-LSP pass.

[LSRA] display mpls te tunnel path
 Tunnel Interface Name : Tunnel1
 Lsp ID : 1.1.1.9 :100 :54
 Hop Information
  Hop 0   172.1.1.1
  Hop 1   172.1.1.2
  Hop 2   2.2.2.9
  Hop 3   172.2.1.1
  Hop 4   172.2.1.2
  Hop 5   3.3.3.9

 Tunnel Interface Name : Tunnel1
 Lsp ID : 1.1.1.9 :100 :32780
 Hop Information
  Hop 0   172.6.1.1
  Hop 1   172.6.1.2
  Hop 2   6.6.6.9
  Hop 3   172.7.1.1
  Hop 4   172.7.1.2
  Hop 5   3.3.3.9

# Run the shutdown command on GE0/0/2 of LSRA.

[LSRA] interface gigabitethernet 0/0/2
[LSRA-GigabitEthernet0/0/2] shutdown
[LSRA-GigabitEthernet0/0/2] quit

Run the display mpls te hot-standby state interface tunnel 1 command on LSRA. You can see that the hot-standby LSP token is 0x0. This means that the hot-standby LSP is not set up even though there are paths for setting up the hot-standby LSP.

[LSRA] display mpls te hot-standby state interface tunnel 1
(s): same path
---------------------------------------------------------------------           
Verbose information about the Tunnel1 hot-standby state                     
---------------------------------------------------------------------           
session id                               : 100                                  
main LSP token                           : 0x51                                 
hot-standby LSP token                    : 0x0                                  
HSB switch result                        : Primary LSP                          
HSB switch reason                        : -                                    
WTR config time                          : 10s                                  
WTR remain time                          : -                                    
using overlapped path                    : -

Configuration Files

LSRA configuration file

#
sysname LSRA
#
vlan batch 100 400 600
#
mpls lsr-id 1.1.1.9                                                             
mpls                                                                            
 mpls te                                                                        
 mpls te srlg path-calculation strict 
 mpls rsvp-te                                                                   
 mpls te cspf 
#
explicit-path pri-path                                                          
 next hop 172.1.1.2                                                             
 next hop 172.2.1.2                                                             
 next hop 3.3.3.9 
#    
interface Vlanif100
 ip address 172.1.1.1 255.255.255.0
 mpls
 mpls te
 mpls te srlg 1
 mpls rsvp-te
#    
interface Vlanif400
 ip address 172.4.1.1 255.255.255.0
 mpls
 mpls te
 mpls te srlg 1
 mpls rsvp-te
#
interface Vlanif600
 ip address 172.6.1.1 255.255.255.0
 mpls
 mpls te
 mpls rsvp-te
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 100
#    
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 600
#
interface GigabitEthernet0/0/3
 port link-type trunk
 port trunk allow-pass vlan 400
#
interface LoopBack1
 ip address 1.1.1.9 255.255.255.255
#
interface Tunnel1
 ip address unnumbered interface LoopBack1
 tunnel-protocol mpls te
 destination 3.3.3.9
 mpls te tunnel-id 100
 mpls te record-route
 mpls te path explicit-path pri-path
 mpls te backup hot-standby                                                     
 mpls te commit
#
ospf 1
 opaque-capability enable
 area 0.0.0.0
  network 1.1.1.9 0.0.0.0                                                       
  network 172.1.1.0 0.0.0.255                                                   
  network 172.4.1.0 0.0.0.255
  network 172.6.1.0 0.0.0.255
  mpls-te enable
#
return

LSRB configuration file

#
sysname LSRB
#
vlan batch 100 200
# 
mpls lsr-id 2.2.2.9
mpls
 mpls te
 mpls rsvp-te
#
interface Vlanif100
 ip address 172.1.1.2 255.255.255.0
 mpls
 mpls te
 mpls rsvp-te
# 
interface Vlanif200
 ip address 172.2.1.1 255.255.255.0
 mpls
 mpls te
 mpls te srlg 2
 mpls rsvp-te
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 100
# 
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 200
#
interface LoopBack1
 ip address 2.2.2.9 255.255.255.255
# 
ospf 1
 opaque-capability enable
 area 0.0.0.0
  network 2.2.2.9 0.0.0.0                                                       
  network 172.1.1.0 0.0.0.255                                                   
  network 172.2.1.0 0.0.0.255                                                   
  mpls-te enable
#
return

LSRC configuration file

#
sysname LSRC
#
vlan batch 200 500 700
#
mpls lsr-id 3.3.3.9
mpls
 mpls te
 mpls rsvp-te
#
interface Vlanif200
 ip address 172.2.1.2 255.255.255.0
 mpls
 mpls te
 mpls rsvp-te
#
interface Vlanif500
 ip address 172.5.1.2 255.255.255.0
 mpls
 mpls te
 mpls rsvp-te
#
interface Vlanif700
 ip address 172.7.1.2 255.255.255.0
 mpls
 mpls te
 mpls rsvp-te
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 200
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 500
#
interface GigabitEthernet0/0/3
 port link-type trunk
 port trunk allow-pass vlan 700
#
interface LoopBack1
 ip address 3.3.3.9 255.255.255.255
#
ospf 1
 opaque-capability enable
 area 0.0.0.0
  network 3.3.3.9 0.0.0.0                                                       
  network 172.2.1.0 0.0.0.255                                                   
  network 172.5.1.0 0.0.0.255                                                   
  network 172.7.1.0 0.0.0.255
  mpls-te enable
#
return

LSRE configuration file

#
sysname LSRE
#
vlan batch 400 500
#
mpls lsr-id 5.5.5.9
mpls
 mpls te
 mpls rsvp-te
#
interface Vlanif400
 ip address 172.4.1.2 255.255.255.0
 mpls
 mpls te
 mpls rsvp-te
#
interface Vlanif500
 ip address 172.5.1.1 255.255.255.0
 mpls
 mpls te
 mpls te srlg 2
 mpls rsvp-te
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 400
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 500
#
interface LoopBack1
 ip address 5.5.5.9 255.255.255.255
#
ospf 1
 opaque-capability enable
 area 0.0.0.0
  network 5.5.5.9 0.0.0.0                                                       
  network 172.4.1.0 0.0.0.255                                                   
  network 172.5.1.0 0.0.0.255
  mpls-te enable
#
return

LSRF configuration file

#
sysname LSRF
#
vlan batch 600 700
#
mpls lsr-id 6.6.6.9
mpls
 mpls te
 mpls rsvp-te
#
interface Vlanif600
 ip address 172.6.1.2 255.255.255.0
 mpls
 mpls te
 mpls rsvp-te
#
interface Vlanif700
 ip address 172.7.1.1 255.255.255.0
 mpls
 mpls te
 mpls rsvp-te
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 600
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 700
#
interface LoopBack1
 ip address 6.6.6.9 255.255.255.255
#
ospf 1
 opaque-capability enable
 area 0.0.0.0
  network 6.6.6.9 0.0.0.0                                                       
  network 172.6.1.0 0.0.0.255                                                   
  network 172.7.1.0 0.0.0.255
  mpls-te enable
#
return