====IOS-XR Lab 8: iBGP with Three Routers part 4 - using loopback peering====
* Loopback interfaces are simply logical interfaces that never go down unless they are admin shut or the hardware has a fault. For this reason, loopbacks are the primary choice to peer neighbors with.
* In this lab, we will continue to use the three routers and covert peering with the IP address on the physical interface to peering with the IP address on the loopback interface.
- Delete all BGP neighbor statements from all routers, commit optional till the end.
- Add OPSF configuration to R1:
- Use OSPF process 1.
- ++Answer|RP/0/RP0/CPU0:R1#conf t
Tue Feb 11 14:22:04.653 UTC
RP/0/RP0/CPU0:R1(config)#router ospf 1++
- Add Router ID: 1.1.1.1, which is the Loopback 0 IP address.
- ++Answer|RP/0/RP0/CPU0:R1(config-ospf)#router-id 1.1.1.1++
- Add all IP addresses/interfaces that are configured on the local router to OSPF area 0.
- ++Answer|Shown are three different options for the same configuration:
RP/0/RP0/CPU0:R1(config-ospf)#area 0
RP/0/RP0/CPU0:R1(config-ospf-ar)#interface loopback 0
RP/0/RP0/CPU0:R1(config-ospf-ar-if)#exit
RP/0/RP0/CPU0:R1(config-ospf-ar)#exit
RP/0/RP0/CPU0:R1(config-ospf)#area 0 interface gigabitEthernet 0/0/0/0
RP/0/RP0/CPU0:R1(config-ospf-ar-if)#exit
RP/0/RP0/CPU0:R1(config-ospf-ar)#exit
RP/0/RP0/CPU0:R1(config-ospf-ar)#exit
RP/0/RP0/CPU0:R1(config-ospf)#exit
RP/0/RP0/CPU0:R1(config)#router ospf 1 area 0 interface gigabitEthernet 0/0/0/1++
- Configure BGP to form a neighborship with the Loopback interfaces of the other two routers.
- Add neighbor statement for neighbor router's loopback interface IP address.
- ++Answer|RP/0/RP0/CPU0:R1(config)#router bgp 65000
RP/0/RP0/CPU0:R1(config-bgp)#neighbor 2.2.2.2++
- Add neighbor to same BGP ASN:
- ++Answer|RP/0/RP0/CPU0:R1(config-bgp-nbr)#remote-as 65000++
- Configure neighbor to use Loopback 0 as the update source:
- ++Answer|RP/0/RP0/CPU0:R1(config-bgp-nbr)#update-source loopback 0++
- Don't forget to add the neighbor to the ipv4 unicast address-family:
- ++Answer|RP/0/RP0/CPU0:R1(config-bgp-nbr)#address-family ipv4 unicast++
- Repeat for each neighbor till all three routers form an iBGP relationship using OSPF.
- Verify:
- RP/0/RP0/CPU0:R1#show ospf database
Tue Feb 11 14:48:26.490 UTC
OSPF Router with ID (1.1.1.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 992 0x80000006 0x0055a2 2
2.2.2.2 2.2.2.2 861 0x80000007 0x006955 3
3.3.3.3 3.3.3.3 44 0x80000005 0x00823e 3
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.0.0.3 2.2.2.2 1106 0x80000002 0x0047d0
10.0.1.3 3.3.3.3 808 0x80000003 0x007099
RP/0/RP0/CPU0:R1#show bgp summ
Tue Feb 11 14:48:42.660 UTC
BGP router identifier 1.1.1.1, local AS number 65000
BGP generic scan interval 60 secs
Non-stop routing is enabled
BGP table state: Active
Table ID: 0xe0000000 RD version: 12
BGP main routing table version 12
BGP NSR Initial initsync version 7 (Reached)
BGP NSR/ISSU Sync-Group versions 0/0
BGP scan interval 60 secs
BGP is operating in STANDALONE mode.
Process RcvTblVer bRIB/RIB LabelVer ImportVer SendTblVer StandbyVer
Speaker 12 12 12 12 12 0
Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down St/PfxRcd
2.2.2.2 0 65000 57 56 12 0 0 00:33:39 3
3.3.3.3 0 65000 35 35 12 0 0 00:31:44 3
- RP/0/RP0/CPU0:R2#show ospf database
Tue Feb 11 14:49:34.669 UTC
OSPF Router with ID (2.2.2.2) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 1060 0x80000006 0x0055a2 2
2.2.2.2 2.2.2.2 927 0x80000007 0x006955 3
3.3.3.3 3.3.3.3 110 0x80000005 0x00823e 3
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.0.0.3 2.2.2.2 1172 0x80000002 0x0047d0
10.0.1.3 3.3.3.3 874 0x80000003 0x007099
RP/0/RP0/CPU0:R2#show bgp summ
Tue Feb 11 14:49:37.776 UTC
BGP router identifier 2.2.2.2, local AS number 65000
BGP generic scan interval 60 secs
Non-stop routing is enabled
BGP table state: Active
Table ID: 0xe0000000 RD version: 34
BGP main routing table version 34
BGP NSR Initial initsync version 8 (Reached)
BGP NSR/ISSU Sync-Group versions 0/0
BGP scan interval 60 secs
BGP is operating in STANDALONE mode.
Process RcvTblVer bRIB/RIB LabelVer ImportVer SendTblVer StandbyVer
Speaker 34 34 34 34 34 0
Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down St/PfxRcd
1.1.1.1 0 65000 71 77 34 0 0 00:34:33 3
3.3.3.3 0 65000 36 36 34 0 0 00:32:48 3
- RP/0/RP0/CPU0:R3#show ospf database
Tue Feb 11 14:50:30.060 UTC
OSPF Router with ID (3.3.3.3) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 1118 0x80000006 0x0055a2 2
2.2.2.2 2.2.2.2 985 0x80000007 0x006955 3
3.3.3.3 3.3.3.3 166 0x80000005 0x00823e 3
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.0.0.3 2.2.2.2 1229 0x80000002 0x0047d0
10.0.1.3 3.3.3.3 930 0x80000003 0x007099
RP/0/RP0/CPU0:R3#show bgp summ
Tue Feb 11 14:50:34.906 UTC
BGP router identifier 3.3.3.3, local AS number 65000
BGP generic scan interval 60 secs
Non-stop routing is enabled
BGP table state: Active
Table ID: 0xe0000000 RD version: 44
BGP main routing table version 44
BGP NSR Initial initsync version 8 (Reached)
BGP NSR/ISSU Sync-Group versions 0/0
BGP scan interval 60 secs
BGP is operating in STANDALONE mode.
Process RcvTblVer bRIB/RIB LabelVer ImportVer SendTblVer StandbyVer
Speaker 44 44 44 44 44 0
Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down St/PfxRcd
1.1.1.1 0 65000 37 37 44 0 0 00:33:37 3
2.2.2.2 0 65000 37 37 44 0 0 00:33:46 3
* Router1's ending configuration: ++Answer|hostname R1
!
interface Loopback0
ipv4 address 1.1.1.1 255.255.255.255
!
interface GigabitEthernet0/0/0/0
description R2; g 0/0/0/0; 10.0.0.3/24
ipv4 address 10.0.0.2 255.255.255.0
!
interface GigabitEthernet0/0/0/2
ipv4 address 10.0.2.2 255.255.255.0
!
router ospf 1
router-id 1.1.1.1
area 0
interface Loopback0
!
interface GigabitEthernet0/0/0/0
!
interface GigabitEthernet0/0/0/1
!
!
!
router bgp 65000
bgp router-id 1.1.1.1
address-family ipv4 unicast
network 1.1.1.1/32
network 10.0.0.0/24
network 10.0.2.0/24
!
neighbor 2.2.2.2
remote-as 65000
update-source Loopback0
address-family ipv4 unicast
!
!
neighbor 3.3.3.3
remote-as 65000
update-source Loopback0
address-family ipv4 unicast
!
!
!
router hsrp
interface GigabitEthernet0/0/0/0
address-family ipv4
hsrp 1
address 10.0.0.1
!
!
!
!
end++
* Router2's ending configuration: ++Answer|hostname R2
!
interface Loopback0
description Loopback0 for BGP
ipv4 address 2.2.2.2 255.255.255.255
!
interface GigabitEthernet0/0/0/0
description R2; g 0/0/0/0; 10.0.0.2/24
ipv4 address 10.0.0.3 255.255.255.0
!
interface GigabitEthernet0/0/0/1
description R3; g 0/0/0/1; 10.0.1.3/24
ipv4 address 10.0.1.2 255.255.255.0
!
router ospf 1
router-id 2.2.2.2
area 0
interface Loopback0
!
interface GigabitEthernet0/0/0/0
!
interface GigabitEthernet0/0/0/1
!
!
!
router bgp 65000
bgp router-id 2.2.2.2
address-family ipv4 unicast
network 2.2.2.2/32
network 10.0.0.0/24
network 10.0.1.0/24
!
neighbor 1.1.1.1
remote-as 65000
update-source Loopback0
address-family ipv4 unicast
!
!
neighbor 3.3.3.3
remote-as 65000
update-source Loopback0
address-family ipv4 unicast
!
!
!
router hsrp
interface GigabitEthernet0/0/0/0
address-family ipv4
hsrp 1
priority 50
address 10.0.0.1
!
!
!
!
end++
* Router3's ending configuration: ++Answer|hostname R3
!
interface Loopback0
description Loopback0 for BGP
ipv4 address 3.3.3.3 255.255.255.255
!
interface GigabitEthernet0/0/0/1
description R2; G 0/0/0/1; 10.0.0.1.2/24
ipv4 address 10.0.1.3 255.255.255.0
!
interface GigabitEthernet0/0/0/2
ipv4 address 10.0.2.3 255.255.255.0
!
router ospf 1
router-id 3.3.3.3
area 0
interface Loopback0
!
interface GigabitEthernet0/0/0/1
!
interface GigabitEthernet0/0/0/2
!
!
!
router bgp 65000
bgp router-id 3.3.3.3
address-family ipv4 unicast
network 3.3.3.3/32
network 10.0.1.0/24
network 10.0.2.0/24
!
neighbor 1.1.1.1
remote-as 65000
update-source Loopback0
address-family ipv4 unicast
!
!
neighbor 2.2.2.2
remote-as 65000
update-source Loopback0
address-family ipv4 unicast
!
!
!
end++
[[:cisco:labs:ios_xr:lab9|IOS-XR Lab 9: iBGP with Three Routers part 5]]\\
[[:cisco:labs:ios_xr|IOS-XR Lab Index]]