Example for Configuring a BGP Confederation
Networking Requirements
As shown in Figure 9-34, there are multiple BGP routers in AS 200. It is required that the number of IBGP connections be reduced.
Configuration Roadmap
The configuration roadmap is as follows:
Configure a BGP confederation on each router in AS 200 to divide AS 200 into three sub-ASs: AS 65001, AS 65002, and AS 65003. Three routers in AS 65001 establish full-mesh IBGP connections to reduce the number of IBGP connections.
Procedure
- Configure an IP address to each interface.
# Configure IP addresses for all interfaces of RouterA.
<Huawei> system-view [Huawei] sysname RouterA [RouterA] interface gigabitethernet 0/0/1 [RouterA-GigabitEthernet0/0/1] ip address 10.1.4.1 255.255.255.0 [RouterA-GigabitEthernet0/0/1] quit [RouterA] interface gigabitethernet 1/0/0 [RouterA-GigabitEthernet1/0/0] ip address 200.1.1.1 255.255.255.0 [RouterA-GigabitEthernet1/0/0] quit [RouterA] interface gigabitethernet 2/0/0 [RouterA-GigabitEthernet2/0/0] ip address 10.1.1.1 255.255.255.0 [RouterA-GigabitEthernet2/0/0] quit [RouterA] interface gigabitethernet 3/0/0 [RouterA-GigabitEthernet3/0/0] ip address 10.1.2.1 255.255.255.0 [RouterA-GigabitEthernet3/0/0] quit [RouterA] interface gigabitethernet 4/0/0 [RouterA-GigabitEthernet4/0/0] ip address 10.1.3.1 255.255.255.0 [RouterA-GigabitEthernet4/0/0] quit
The configurations of RouterB, RouterC, RouterD, RouterE and RouterF are similar to the configuration of RouterA, and are not mentioned here.
- Configure the BGP confederation.
# Configure Router A.
[RouterA] bgp 65001
[RouterA-bgp] router-id 1.1.1.1
[RouterA-bgp] confederation id 200
[RouterA-bgp] confederation peer-as 65002 65003
[RouterA-bgp] peer 10.1.1.2 as-number 65002
[RouterA-bgp] peer 10.1.2.2 as-number 65003
[RouterA-bgp] ipv4-family unicast
[RouterA-bgp-af-ipv4] peer 10.1.1.2 next-hop-local
[RouterA-bgp-af-ipv4] peer 10.1.2.2 next-hop-local
[RouterA-bgp-af-ipv4] quit
# Configure Router B.
[RouterB] bgp 65002
[RouterB-bgp] router-id 2.2.2.2
[RouterB-bgp] confederation id 200
[RouterB-bgp] confederation peer-as 65001
[RouterB-bgp] peer 10.1.1.1 as-number 65001
[RouterB-bgp] quit
# Configure Router C.
[RouterC] bgp 65003
[RouterC-bgp] router-id 3.3.3.3
[RouterC-bgp] confederation id 200
[RouterC-bgp] confederation peer-as 65001
[RouterC-bgp] peer 10.1.2.1 as-number 65001
[RouterC-bgp] quit
- Configure IBGP connections inside AS 65001.
# Configure Router A.
[RouterA] bgp 65001
[RouterA-bgp] peer 10.1.3.2 as-number 65001
[RouterA-bgp] peer 10.1.4.2 as-number 65001
[RouterA-bgp] ipv4-family unicast
[RouterA-bgp-af-ipv4] peer 10.1.3.2 next-hop-local
[RouterA-bgp-af-ipv4] peer 10.1.4.2 next-hop-local
[RouterA-bgp-af-ipv4] quit
# Configure Router D.
[RouterD] bgp 65001
[RouterD-bgp] router-id 4.4.4.4
[RouterD-bgp] confederation id 200
[RouterD-bgp] peer 10.1.3.1 as-number 65001
[RouterD-bgp] peer 10.1.5.2 as-number 65001
[RouterD-bgp] quit
# Configure Router E.
[RouterE] bgp 65001
[RouterE-bgp] router-id 5.5.5.5
[RouterE-bgp] confederation id 200
[RouterE-bgp] peer 10.1.4.1 as-number 65001
[RouterE-bgp] peer 10.1.5.1 as-number 65001
[RouterE-bgp] quit
- Configure the EBGP connection between AS 100 and AS 200.
# Configure Router A.
[RouterA] bgp 65001
[RouterA-bgp] peer 200.1.1.2 as-number 100
[RouterA-bgp] quit
# Configure Router F.
[RouterF] bgp 100
[RouterF-bgp] router-id 6.6.6.6
[RouterF-bgp] peer 200.1.1.1 as-number 200
[RouterF-bgp] ipv4-family unicast
[RouterF-bgp-af-ipv4] network 9.1.1.0 255.255.255.0
[RouterF-bgp-af-ipv4] quit
- Verify the configuration.
# Check the routing table of Router B.
[RouterB] display bgp routing-table
BGP Local router ID is 2.2.2.2
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 9.1.1.0/24 10.1.1.1 0 100 0 (65001) 100i
[RouterB] display bgp routing-table 9.1.1.0
BGP local router ID : 2.2.2.2 Local AS number : 65002 Paths: 1 available, 1 best, 1 select BGP routing table entry information of 9.1.1.0/24: From: 10.1.1.1 (1.1.1.1) Route Duration: 00h12m29s Relay IP Nexthop: 0.0.0.0 Relay IP Out-Interface: GigabitEthernet1/0/0 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 Router D.
[RouterD] display bgp routing-table
BGP Local router ID is 4.4.4.4
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 9.1.1.0/24 10.1.3.1 0 100 0 100i
[RouterD] display bgp routing-table 9.1.1.0
BGP local router ID : 4.4.4.4 Local AS number : 65001 Paths: 1 available, 1 best, 1 select BGP routing table entry information of 9.1.1.0/24: From: 10.1.3.1 (1.1.1.1) Route Duration: 00h23m57s Relay IP Nexthop: 0.0.0.0 Relay IP Out-Interface: GigabitEthernet1/0/0 Original nexthop: 10.1.3.1 Qos information : 0x0 AS-path 100, origin igp, MED 0, localpref 100, pref-val 0, valid, internal-confed, best, select, active, pre 255 Not advertised to any peer yet
Configuration Files
Configuration file of Router A
#
sysname RouterA
#
interface GigabitEthernet0/0/1
ip address 10.1.4.1 255.255.255.0
#
interface GigabitEthernet1/0/0
ip address 200.1.1.1 255.255.255.0
#
interface GigabitEthernet2/0/0
ip address 10.1.1.1 255.255.255.0
#
interface GigabitEthernet3/0/0
ip address 10.1.2.1 255.255.255.0
#
interface GigabitEthernet4/0/0
ip address 10.1.3.1 255.255.255.0
#
bgp 65001
router-id 1.1.1.1
confederation id 200
confederation peer-as 65002 65003
peer 200.1.1.2 as-number 100
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
#
ipv4-family unicast
undo synchronization
peer 200.1.1.2 enable
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
#
return
Configuration file of Router B
#
sysname RouterB
#
interface GigabitEthernet1/0/0
ip address 10.1.1.2 255.255.255.0
#
bgp 65002
router-id 2.2.2.2
confederation id 200
confederation peer-as 65001
peer 10.1.1.1 as-number 65001
#
ipv4-family unicast
undo synchronization
peer 10.1.1.1 enable
#
return
The configuration file of Router C is similar to that of Router B, and is not mentioned here.
Configuration file of Router D
#
sysname RouterD
#
interface GigabitEthernet1/0/0
ip address 10.1.3.2 255.255.255.0
#
interface GigabitEthernet2/0/0
ip address 10.1.5.1 255.255.255.0
#
bgp 65001
router-id 4.4.4.4
confederation id 200
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
The configuration file of Router E is similar to that of Router D, and is not mentioned here.
Configuration file of Router F
#
sysname RouterF
#
interface GigabitEthernet1/0/0
ip address 200.1.1.2 255.255.255.0
#
interface GigabitEthernet2/0/0
ip address 9.1.1.1 255.255.255.0
#
bgp 100
router-id 6.6.6.6
peer 200.1.1.1 as-number 200
#
ipv4-family unicast
undo synchronization
network 9.1.1.0 255.255.255.0
peer 200.1.1.1 enable
#
return