Example for Configuring BGP-LS

BGP-link state (LS) enables BGP to report topology information collected by IGPs to the controller.

Networking Requirements

BGP-LS is a new method of collecting topology information. With powerful routing capabilities of BGP, BGP-LS has the following advantages:
  • Reduces computing capability requirements and spares the necessity of IGPs on the controller.
  • Facilitates route selection and calculation on the controller by using BGP to summarize process or AS topology information and report the complete information to the controller.
  • Requires only one routing protocol (BGP) to report topology information to the controller.

In Figure 1, Device C is connected to the controller and reports topology information to the controller. Device A, Device B, Device C, and Device D use IS-IS to communicate with each other at the network layer. Device A, Device B, and Device C reside in area 10, whereas Device D resides in area 20. Device A and Device B are Level-1 devices, Device C is a Level-1-2 device, and Device D is a Level-2 device.

Figure 1 Configuring BGP-LS

Interfaces 1 through 4 in this example represent GE 0/1/0, GE 0/1/8, GE 0/1/16, and GE 0/1/24, respectively.


Configuration Roadmap

The configuration roadmap is as follows:

  1. Configure an IP address for each interface on each router.

  2. Configure basic IS-IS functions.

  3. Deploy BGP-LS on Device C and the controller.

Data Preparation

To complete the configuration, you need the following data:

  • Area addresses of Device A, Device B, Device C, and Device D

  • Levels of Device A, Device B, Device C, and Device D

  • BGP-LS identifier of Device C

  • BGP AS numbers, BGP-LS domain AS numbers, and BGP-LS domain IDs of Device C and the controller

Procedure

  1. Assign an IP address to each interface on each router. For configuration details, see Configuration Files in this section.
  2. Configure basic IS-IS functions.

    # Configure Device A.

    [~DeviceA] isis 1
[*DeviceA-isis-1] is-level level-1
[*DeviceA-isis-1] network-entity 10.0000.0000.0001.00
[*DeviceA-isis-1] quit
[*DeviceA] interface gigabitethernet 0/1/8
[*DeviceA-GigabitEthernet0/1/8] isis enable 1
[*DeviceA-GigabitEthernet0/1/8] commit
[~DeviceA-GigabitEthernet0/1/8] quit

    # Configure Device B.

    [~DeviceB] isis 1
[*DeviceB-isis-1] is-level level-1
[*DeviceB-isis-1] network-entity 10.0000.0000.0002.00
[*DeviceB-isis-1] quit
[*DeviceB] interface gigabitethernet 0/1/24
[*DeviceB-GigabitEthernet0/1/24] isis enable 1
[*DeviceA-GigabitEthernet0/1/24] commit
[~DeviceB-GigabitEthernet0/1/24] quit

    # Configure Device C.

    [~DeviceC] isis 1
[*DeviceC-isis-1] network-entity 10.0000.0000.0003.00
[*DeviceC-isis-1] quit
[*DeviceC] interface gigabitethernet 0/1/8
[*DeviceC-GigabitEthernet0/1/8] isis enable 1
[*DeviceC-GigabitEthernet0/1/8] quit
[*DeviceC] interface gigabitethernet 0/1/16
[*DeviceC-GigabitEthernet0/1/16] isis enable 1
[*DeviceC-GigabitEthernet0/1/16] quit
[*DeviceC] interface gigabitethernet 0/1/24
[*DeviceC-GigabitEthernet0/1/24] isis enable 1
[*DeviceC-GigabitEthernet0/1/24] commit
[~DeviceC-GigabitEthernet0/1/24] quit

    # Configure Device D.

    [~DeviceD] isis 1
[*DeviceD-isis-1] is-level level-2
[*DeviceD-isis-1] network-entity 20.0000.0000.0004.00
[*DeviceD-isis-1] quit
[*DeviceD] interface gigabitethernet 0/1/16
[*DeviceD-GigabitEthernet0/1/16] isis enable 1
[*DeviceD-GigabitEthernet0/1/16] quit
[*DeviceD] interface LoopBack0
[*DeviceD-LoopBack0] isis enable 1
[*DeviceD-LoopBack0] commit
[~DeviceD-LoopBack0] quit

    # Check IS-IS routing information on each router. The following example uses the command output on Device C.

    [~DeviceC] display isis route
                         Route information for ISIS(1)
                         -----------------------------

                        ISIS(1) Level-1 Forwarding Table
                        --------------------------------

IPV4 Destination   IntCost    ExtCost ExitInterface     NextHop         Flags
-------------------------------------------------------------------------------
1.1.1.0/24         10         NULL    GE0/1/0           Direct          D/-/L/-
10.1.1.0/24        10         NULL    GE0/1/8           Direct          D/-/L/-
10.1.2.0/24        10         NULL    GE0/1/24           Direct          D/-/L/-
192.168.0.0/24     10         NULL    GE0/1/16           Direct          D/-/L/-
     Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut,
                               U-Up/Down Bit Set


                        ISIS(1) Level-2 Forwarding Table
                        --------------------------------

IPV4 Destination   IntCost    ExtCost ExitInterface     NextHop         Flags
-------------------------------------------------------------------------------
1.1.1.0/24         10         NULL    GE0/1/0           Direct          D/-/L/-
10.1.1.0/24        10         NULL    GE0/1/8           Direct          D/-/L/-
10.1.2.0/24        10         NULL    GE0/1/24           Direct          D/-/L/-
172.16.1.1/32      10         NULL    GE0/1/16           192.168.0.2     A/-/-/-
192.168.0.0/24     10         NULL    GE0/1/16           Direct          D/-/L/-
     Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut,
                               U-Up/Down Bit Set

  3. Deploy BGP-LS on Device C and the controller.

    # Enable IS-IS topology advertisement to BGP on Device C.

    [~DeviceC] isis 1
[*DeviceC-isis-1] bgp-ls enable
[*DeviceC-isis-1] bgp-ls identifier 20
[*DeviceC-isis-1] commit
[~DeviceC-isis-1] quit

    # Enable BGP-LS on Device C and configure the controller as a BGP-LS peer of Device C.

    [~DeviceC] bgp 100
[*DeviceC-bgp] peer 1.1.1.2 as-number 100
[*DeviceC-bgp] link-state-family unicast
[*DeviceC-bgp-af-ls] peer 1.1.1.2 enable
[*DeviceC-bgp-af-ls] commit
[~DeviceC-bgp-af-ls] quit
[~DeviceC-bgp] quit

    # Enable BGP-LS on the controller and configure Device C as a BGP-LS peer of the controller.

    [~Controller] bgp 100
[*Controller-bgp] peer 1.1.1.1 as-number 100
[*Controller-bgp] link-state-family unicast
[*Controller-bgp-af-ls] peer 1.1.1.1 enable
[*Controller-bgp-af-ls] commit
[~Controller-bgp-af-ls] quit
[~Controller-bgp] quit

  4. Verify the configuration.

    # Display information about BGP-LS peers and their status on Device C.

    [~DeviceC] display bgp link-state unicast peer
 BGP local router ID : 10.1.1.1
 Local AS number : 100
 Total number of peers : 1                 Peers in established state : 1

  Peer            V          AS  MsgRcvd  MsgSent  OutQ  Up/Down       State  PrefRcv
  1.1.1.2         4         100       27       48     0 00:29:11 Established       17

    # Display BGP-LS routes on Device C.

    [~DeviceC] display bgp link-state unicast routing-table
 BGP Local router ID is 10.1.1.1
 Status codes: * - valid, > - best, d - damped, x - best external, a - add path,
               h - history,  i - internal, s - suppressed, S - Stale
               Origin : i - IGP, e - EGP, ? - incomplete


 Total Number of Node Routes: 6
 *>     Network  : [NODE][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0002.00]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [NODE][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [NODE][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [NODE][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.00]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [NODE][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.02]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [NODE][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.01]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?

 Total Number of Link Routes: 8
 *>     Network  : [LINK][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0002.00]][REMOTE[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.02]][LINK[if-address0.0.0.0][peer-address0.0.0.0][if-address::][peer-address::]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [LINK][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][REMOTE[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.02]][LINK[if-address0.0.0.0][peer-address0.0.0.0][if-address::][peer-address::]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [LINK][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.02]][REMOTE[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0002.00]][LINK[if-address0.0.0.0][peer-address0.0.0.0][if-address::][peer-address::]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [LINK][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.02]][REMOTE[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][LINK[if-address0.0.0.0][peer-address0.0.0.0][if-address::][peer-address::]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [LINK][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][REMOTE[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.01]][LINK[if-address0.0.0.0][peer-address0.0.0.0][if-address::][peer-address::]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [LINK][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.00]][REMOTE[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.01]][LINK[if-address0.0.0.0][peer-address0.0.0.0][if-address::][peer-address::]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [LINK][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.01]][REMOTE[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][LINK[if-address0.0.0.0][peer-address0.0.0.0][if-address::][peer-address::]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [LINK][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.01]][REMOTE[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.00]][LINK[if-address0.0.0.0][peer-address0.0.0.0][if-address::][peer-address::]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?

 Total Number of IPv4 Prefix Routes: 11
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0002.00]][PREFIX[ospf-route-type0][prefix10.1.2.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][PREFIX[ospf-route-type0][prefix1.1.1.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][PREFIX[ospf-route-type0][prefix10.1.1.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][PREFIX[ospf-route-type0][prefix10.1.2.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-1][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][PREFIX[ospf-route-type0][prefix192.168.0.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][PREFIX[ospf-route-type0][prefix1.1.1.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][PREFIX[ospf-route-type0][prefix10.1.1.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][PREFIX[ospf-route-type0][prefix10.1.2.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0003.00]][PREFIX[ospf-route-type0][prefix192.168.0.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.00]][PREFIX[ospf-route-type0][prefix192.168.0.0/24]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?
 *>     Network  : [IPV4-PREFIX][ISIS-LEVEL-2][IDENTIFIER20][LOCAL[as100][bgp-ls-identifier10.1.1.1][ospf-area-id0.0.0.0][igp-router-id0000.0000.0004.00]][PREFIX[ospf-route-type0][prefix172.16.1.1/32]]
        NextHop  : 0.0.0.0                                  LocPrf    :
        MED      : 0                                        PrefVal   : 0
        Path/Ogn :  ?

    The preceding command output shows that Device C obtains the topology information on the whole IS-IS network. Device C can use BGP-LS routes to report the topology information to its BGP-LS peer (the controller).

Configuration Files

  • Device A configuration file

    #
sysname DeviceA
#
isis 1
 is-level level-1
 network-entity 10.0000.0000.0001.00
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.1.1.2 255.255.255.0
 isis enable 1
#
return

  • Device B configuration file

    #
sysname DeviceB
#
isis 1
 is-level level-1
 network-entity 10.0000.0000.0002.00
#
interface GigabitEthernet0/1/24
 undo shutdown
 ip address 10.1.2.2 255.255.255.0
 isis enable 1
#
return

  • Device C configuration file

    #
sysname DeviceC
#
isis 1
 bgp-ls enable level-1-2
 bgp-ls identifier 20 
 network-entity 10.0000.0000.0003.00
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 1.1.1.1 255.255.255.0
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.1.1.1 255.255.255.0
 isis enable 1
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 192.168.0.1 255.255.255.0
 isis enable 1
#
interface GigabitEthernet0/1/24
 undo shutdown
 ip address 10.1.2.1 255.255.255.0
 isis enable 1
#
bgp 100
 peer 1.1.1.2 as-number 100
 #
 ipv4-family unicast
  undo synchronization 
  peer 1.1.1.2 enable
 #
 link-state-family unicast
  peer 1.1.1.2 enable
#
return

  • Device D configuration file

    #
sysname DeviceD
#
isis 1
 is-level level-2
 network-entity 20.0000.0000.0004.00
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 192.168.0.2 255.255.255.0
 isis enable 1
#
interface LoopBack0
 ip address 172.16.1.1 255.255.255.255
 isis enable 1
#
return

  • Controller configuration file

    #
sysname Controller
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 1.1.1.2 255.255.255.0
#
bgp 100
 peer 1.1.1.1 as-number 100
 #
 ipv4-family unicast
  undo synchronization 
  peer 1.1.1.1 enable
 #
 link-state-family unicast
  peer 1.1.1.1 enable
#
return
Parent Topic: Configuration Examples for BGP
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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