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Example for Configuring a BGP Confederation

Networking Requirements

In Figure 1, there are multiple BGP switches in AS 200. It is required that the number of IBGP connections be reduced.

In this scenario, ensure that all connected interfaces have STP disabled. 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 diagram of configuring a BGP confederation

Configuration Roadmap

The configuration roadmap is as follows:

  1. Configure a BGP confederation on each switch in AS 200 to divide AS 200 into three sub-ASs: AS 65001, AS 65002, and AS 65003. Three switches in AS 65001 establish full-mesh IBGP connections to reduce the number of IBGP connections.

Procedure

  1. Create VLANs and add interfaces to the corresponding VLANs. 

    <HUAWEI> system-view
[HUAWEI] sysname SwitchA
[SwitchA] vlan batch 10 20 30 40 60
[SwitchA] interface gigabitethernet 0/0/1
[SwitchA-GigabitEthernet0/0/1] port link-type trunk
[SwitchA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[SwitchA-GigabitEthernet0/0/1] quit
[SwitchA] interface gigabitethernet 0/0/2
[SwitchA-GigabitEthernet0/0/2] port link-type trunk
[SwitchA-GigabitEthernet0/0/2] port trunk allow-pass vlan 20
[SwitchA-GigabitEthernet0/0/2] quit
[SwitchA] interface gigabitethernet 0/0/3
[SwitchA-GigabitEthernet0/0/3] port link-type trunk
[SwitchA-GigabitEthernet0/0/3] port trunk allow-pass vlan 30
[SwitchA-GigabitEthernet0/0/3] quit
[SwitchA] interface gigabitethernet 0/0/4
[SwitchA-GigabitEthernet0/0/4] port link-type trunk
[SwitchA-GigabitEthernet0/0/4] port trunk allow-pass vlan 40
[SwitchA-GigabitEthernet0/0/4] quit
[SwitchA] interface gigabitethernet 0/0/5
[SwitchA-GigabitEthernet0/0/5] port link-type trunk
[SwitchA-GigabitEthernet0/0/5] port trunk allow-pass vlan 60
[SwitchA-GigabitEthernet0/0/5] quit

    The configurations of SwitchB, SwitchC, SwitchD, SwitchE, and SwitchF are similar to the configuration of SwitchA, and are not mentioned here.

  2. Assign an IP address to each VLANIF interface. 

    [SwitchA] interface vlanif 10
[SwitchA-Vlanif10] ip address 10.1.1.1 24
[SwitchA-Vlanif10] quit
[SwitchA] interface vlanif 20
[SwitchA-Vlanif20] ip address 10.1.2.1 24
[SwitchA-Vlanif20] quit
[SwitchA] interface vlanif 30
[SwitchA-Vlanif30] ip address 10.1.3.1 24
[SwitchA-Vlanif30] quit
[SwitchA] interface vlanif 40
[SwitchA-Vlanif40] ip address 10.1.4.1 24
[SwitchA-Vlanif40] quit
[SwitchA] interface vlanif 60
[SwitchA-Vlanif60] ip address 192.168.1.1 24
[SwitchA-Vlanif60] quit

    The configurations of SwitchB, SwitchC, SwitchD, SwitchE, and SwitchF are similar to the configuration of SwitchA, and are not mentioned here.

  3. Configure the BGP confederation.

    # Configure SwitchA.

    [SwitchA] bgp 65001
[SwitchA-bgp] router-id 172.16.1.1
[SwitchA-bgp] confederation id 200
[SwitchA-bgp] confederation peer-as 65002 65003
[SwitchA-bgp] peer 10.1.1.2 as-number 65002 
[SwitchA-bgp] peer 10.1.2.2 as-number 65003
[SwitchA-bgp] ipv4-family unicast 
[SwitchA-bgp-af-ipv4] peer 10.1.1.2 next-hop-local
[SwitchA-bgp-af-ipv4] peer 10.1.2.2 next-hop-local 
[SwitchA-bgp-af-ipv4] quit
[SwitchA-bgp] quit

    # Configure SwitchB.

    [SwitchB] bgp 65002
[SwitchB-bgp] router-id 172.16.2.2
[SwitchB-bgp] confederation id 200
[SwitchB-bgp] confederation peer-as 65001 65003
[SwitchB-bgp] peer 10.1.1.1 as-number 65001
[SwitchB-bgp] quit

    # Configure SwitchC.

    [SwitchC] bgp 65003
[SwitchC-bgp] router-id 172.16.3.3
[SwitchC-bgp] confederation id 200
[SwitchC-bgp] confederation peer-as 65001 65002
[SwitchC-bgp] peer 10.1.2.1 as-number 65001
[SwitchC-bgp] quit

  4. Establish IBGP connection in AS 65001.

    # Configure SwitchA.

    [SwitchA] bgp 65001
[SwitchA-bgp] peer 10.1.3.2 as-number 65001
[SwitchA-bgp] peer 10.1.4.2 as-number 65001
[SwitchA-bgp] ipv4-family unicast
[SwitchA-bgp-af-ipv4] peer 10.1.3.2 next-hop-local
[SwitchA-bgp-af-ipv4] peer 10.1.4.2 next-hop-local
[SwitchA-bgp-af-ipv4] quit

    # Configure SwitchD.

    [SwitchD] bgp 65001
[SwitchD-bgp] router-id 172.16.4.4
[SwitchD-bgp] peer 10.1.3.1 as-number 65001
[SwitchD-bgp] peer 10.1.5.2 as-number 65001 
[SwitchD-bgp] quit

    # Configure SwitchE.

    [SwitchE] bgp 65001
[SwitchE-bgp] router-id 172.16.5.5
[SwitchE-bgp] peer 10.1.4.1 as-number 65001
[SwitchE-bgp] peer 10.1.5.1 as-number 65001 
[SwitchE-bgp] quit

  5. Establish an EBGP connection between AS 100 and AS 200.

    # Configure SwitchA.

    [SwitchA] bgp 65001
[SwitchA-bgp] peer 192.168.1.2 as-number 100 
[SwitchA-bgp] quit

    # Configure SwitchF.

    [SwitchF] bgp 100
[SwitchF-bgp] router-id 172.16.6.6 
[SwitchF-bgp] peer 192.168.1.1 as-number 200 
[SwitchF-bgp] ipv4-family unicast 
[SwitchF-bgp-af-ipv4] network 10.0.1.0 255.255.255.0
[SwitchF-bgp-af-ipv4] quit
[SwitchF-bgp] quit

  6. Verify the configuration.

    # Check the BGP routing table of SwitchB.

    [SwitchB] display bgp routing-table
 
 BGP Local router ID is 172.16.2.2
 Status codes: * - valid, > - best, d - damped,
               h - history,  i - internal, s - suppressed, S - Stale
               Origin : i - IGP, e - EGP, ? - incomplete
 Total Number of Routes: 1
 
     Network            NextHop        MED        LocPrf    PrefVal Path/Ogn
 
 *>i  10.0.1.0/24        10.1.1.1        0          100        0      (65001) 100i
[SwitchB] display bgp routing-table 10.0.1.0

BGP local router ID : 172.16.2.2
 Local AS number : 65002
 Paths:   1 available, 1 best, 1 select
 BGP routing table entry information of 10.0.1.0/24:
 From: 10.1.1.1 (172.16.1.1)
 Route Duration: 00h01m22s
 Relay IP Nexthop: 0.0.0.0
 Relay IP Out-Interface: Vlanif10
 Original nexthop: 10.1.1.1
 Qos information : 0x0
 AS-path (65001) 100, origin igp, MED 0, localpref 100, pref-val 0, valid, external-confed, best,select, active, pre 255
 Not advertised to any peer yet

    # Check the BGP routing table of SwitchD.

    [SwitchD] display bgp routing-table
 
 BGP Local router ID is 172.16.4.4
 Status codes: * - valid, > - best, d - damped,
               h - history,  i - internal, s - suppressed, S - Stale
               Origin : i - IGP, e - EGP, ? - incomplete
 
 Total Number of Routes: 1
     Network            NextHop        MED        LocPrf    PrefVal Path/Ogn
 
 *>i  10.0.1.0/24        10.1.3.1        0          100        0      100i
[SwitchD] display bgp routing-table 10.0.1.0
 
 BGP local router ID : 172.16.4.4
 Local AS number : 65001
 Paths:   1 available, 1 best, 1 select
 BGP routing table entry information of 10.0.1.0/24:
 From: 10.1.3.1 (172.16.1.1)
 Route Duration: 00h18m34s
 Relay IP Nexthop: 0.0.0.0
 Relay IP Out-Interface: Vlanif30
 Original nexthop: 10.1.3.1
 Qos information : 0x0
 AS-path 100, origin igp, MED 0, localpref 100, pref-val 0, valid, internal, best,select, active, pre 255
 Not advertised to any peer yet

Configuration Files

  • SwitchA configuration file

    #
sysname SwitchA
#
vlan batch 10 20 30 40 60
#
interface Vlanif10
 ip address 10.1.1.1 255.255.255.0
#
interface Vlanif20
 ip address 10.1.2.1 255.255.255.0
#
interface Vlanif30
 ip address 10.1.3.1 255.255.255.0
#
interface Vlanif40
 ip address 10.1.4.1 255.255.255.0
#
interface Vlanif60
 ip address 192.168.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/3
 port link-type trunk
 port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/4
 port link-type trunk
 port trunk allow-pass vlan 40
#
interface GigabitEthernet0/0/5
 port link-type trunk
 port trunk allow-pass vlan 60
#
bgp 65001
 router-id 172.16.1.1
 confederation id 200
 confederation peer-as 65002 65003
 peer 10.1.1.2 as-number 65002
 peer 10.1.2.2 as-number 65003
 peer 10.1.3.2 as-number 65001
 peer 10.1.4.2 as-number 65001
 peer 192.168.1.2 as-number 100
 #
 ipv4-family unicast
  undo synchronization
  peer 10.1.1.2 enable
  peer 10.1.1.2 next-hop-local
  peer 10.1.2.2 enable
  peer 10.1.2.2 next-hop-local
  peer 10.1.3.2 enable
  peer 10.1.3.2 next-hop-local
  peer 10.1.4.2 enable
  peer 10.1.4.2 next-hop-local
  peer 192.168.1.2 enable
#
return

  • SwitchB configuration file

    #
sysname SwitchB
#
vlan batch 10
#
interface Vlanif10
 ip address 10.1.1.2 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10
#
bgp 65002
 router-id 172.16.2.2
 confederation id 200
 confederation peer-as 65001 65003
 peer 10.1.1.1 as-number 65001
 #
 ipv4-family unicast
  undo synchronization
  peer 10.1.1.1 enable
#
return

  • SwitchC configuration file

    #
sysname SwitchC
#
vlan batch 20
#
interface Vlanif20
 ip address 10.1.2.2 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 20
#
bgp 65003
 router-id 172.16.3.3
 confederation id 200
 confederation peer-as 65001 65002
 peer 10.1.2.1 as-number 65001
 #
 ipv4-family unicast
  undo synchronization
  peer 10.1.2.1 enable
#
return

  • SwitchD configuration file

    #
sysname SwitchD
#
vlan batch 30 50
#
interface Vlanif30
 ip address 10.1.3.2 255.255.255.0
#
interface Vlanif50
 ip address 10.1.5.1 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 50
#
bgp 65001
 router-id 172.16.4.4
 peer 10.1.3.1 as-number 65001
 peer 10.1.5.2 as-number 65001
 #
 ipv4-family unicast
  undo synchronization
  peer 10.1.3.1 enable
  peer 10.1.5.2 enable
#
return

  • SwitchE configuration file

    #
sysname SwitchE
#
vlan batch 40 50
#
interface Vlanif40
 ip address 10.1.4.2 255.255.255.0
#
interface Vlanif50
 ip address 10.1.5.2 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 40
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 50
#
bgp 65001
 router-id 172.16.5.5
 peer 10.1.4.1 as-number 65001
 peer 10.1.5.1 as-number 65001
 #
 ipv4-family unicast
  undo synchronization
  peer 10.1.4.1 enable
  peer 10.1.5.1 enable
#
return

  • SwitchF configuration file

    #
sysname SwitchF
#
vlan batch 60 70
#
interface Vlanif60
 ip address 192.168.1.2 255.255.255.0
#
interface Vlanif70
 ip address 10.0.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 60
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 70
#
bgp 100
 router-id 172.16.6.6
 peer 192.168.1.1 as-number 200
 #
 ipv4-family unicast
  undo synchronization  
  network 10.0.1.0 255.255.255.0
  peer 192.168.1.1 enable
#          
return
Parent Topic: Configuration Examples for BGP
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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