Table of Contents

Lab 16: eBGP with OSPF underlay

Task Instructions:

  1. Physical interfaces use a CIDR of /24.
  2. Loopback interfaces use a CIDR of /32.
  3. Use Loopback 0 as the router-id for OSPF and BGP.
  4. Configure r2 and r3 in OSPF Area 0.
  5. Configure r1 and r2 in OSPF Area 1.
  6. Configure r3 and r4 in OSPF Area 2.
  7. Verify OSPF database.
  8. Verify all routers are able to ping each other.
  9. Configure r1 in BGP AS 65000.
  10. Configure r4 in BGP AS 65001.
  11. Configure r1 and r4 to form an eBGP neighborship.
  12. Verify BGP neighborship is Established.

Answer Section

Task 1

r1 

hostname r1
!
interface GigabitEthernet1
 no shutdown
 ip address 12.1.1.1 255.255.255.0

r2 

hostname r2
!
interface GigabitEthernet1
 no shutdown
 ip address 12.1.1.2 255.255.255.0
!
interface GigabitEthernet2
 no shutdown
 ip address 23.1.1.2 255.255.255.0

r3 

hostname r3
!
interface GigabitEthernet1
 no shutdown
 ip address 34.1.1.3 255.255.255.0
!
interface GigabitEthernet2
 no shutdown
 ip address 23.1.1.3 255.255.255.0

r4 

hostname r4
!
interface GigabitEthernet1
 no shutdown
 ip address 34.1.1.4 255.255.255.0

Task 2

r1 

interface Loopback0
 ip address 1.1.1.1 255.255.255.255

r2 

interface Loopback0
 ip address 2.2.2.2 255.255.255.255

r3 

interface Loopback0
 ip address 3.3.3.3 255.255.255.255

r4 

interface Loopback0
 ip address 4.4.4.4 255.255.255.255

Task 4

r2 

router ospf 1
 router-id 2.2.2.2
 network 2.2.2.2 0.0.0.0 area 0
 network 23.1.1.2 0.0.0.0 area 0

r3 

router ospf 1
 router-id 3.3.3.3
 network 3.3.3.3 0.0.0.0 area 0
 network 23.1.1.3 0.0.0.0 area 0

Task 5

r1 

router ospf 1
 router-id 1.1.1.1
 network 1.1.1.1 0.0.0.0 area 1
 network 12.1.1.1 0.0.0.0 area 1

r2 

router ospf 1
 network 12.1.1.2 0.0.0.0 area 1

Task 6

r3 

router ospf 1
 network 34.1.1.3 0.0.0.0 area 2

r4 

router ospf 1
 router-id 4.4.4.4
 network 4.4.4.4 0.0.0.0 area 2
 network 34.1.1.4 0.0.0.0 area 2

Task 7

r1 

r1#show ip ospf database topology | b Summary
                Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
2.2.2.2         2.2.2.2         476         0x80000003 0x00F633
3.3.3.3         2.2.2.2         476         0x80000003 0x00D252
4.4.4.4         2.2.2.2         476         0x80000003 0x00AE71
23.1.1.0        2.2.2.2         717         0x80000007 0x00080D
34.1.1.0        2.2.2.2         476         0x80000007 0x008286

r2 

r2#show ip ospf database topology | b Summary
                Summary Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
1.1.1.1         2.2.2.2         755         0x80000003 0x002FFD
4.4.4.4         3.3.3.3         595         0x80000003 0x008696
12.1.1.0        2.2.2.2         755         0x80000003 0x009F84
34.1.1.0        3.3.3.3         595         0x80000005 0x005EA9

                Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.1.1.1         1.1.1.1         561         0x8000000E 0x00C326 2         
2.2.2.2         2.2.2.2         755         0x8000000D 0x007184 1         

                Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
12.1.1.2        2.2.2.2         755         0x80000003 0x000E06

                Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
2.2.2.2         2.2.2.2         514         0x80000003 0x00F633
3.3.3.3         2.2.2.2         514         0x80000003 0x00D252
4.4.4.4         2.2.2.2         514         0x80000003 0x00AE71
23.1.1.0        2.2.2.2         755         0x80000007 0x00080D
34.1.1.0        2.2.2.2         514         0x80000007 0x008286

r3 

r3#show ip ospf database topology | b Summary
                Summary Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
1.1.1.1         2.2.2.2         756         0x80000003 0x002FFD
4.4.4.4         3.3.3.3         594         0x80000003 0x008696
12.1.1.0        2.2.2.2         756         0x80000003 0x009F84
34.1.1.0        3.3.3.3         594         0x80000005 0x005EA9

                Router Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum Link count
3.3.3.3         3.3.3.3         594         0x80000005 0x00E4E1 1         
4.4.4.4         4.4.4.4         338         0x80000006 0x006F2D 2         

                Net Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum
34.1.1.4        4.4.4.4         338         0x80000003 0x00479C

                Summary Net Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum
1.1.1.1         3.3.3.3         594         0x80000003 0x001B0D
2.2.2.2         3.3.3.3         594         0x80000003 0x00E242
3.3.3.3         3.3.3.3         594         0x80000003 0x00AA77
12.1.1.0        3.3.3.3         594         0x80000003 0x008B93
23.1.1.0        3.3.3.3         594         0x80000003 0x00F123

r4 

r4#show ip ospf database topology | b Summary
                Summary Net Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum
1.1.1.1         3.3.3.3         595         0x80000003 0x001B0D
2.2.2.2         3.3.3.3         595         0x80000003 0x00E242
3.3.3.3         3.3.3.3         595         0x80000003 0x00AA77
12.1.1.0        3.3.3.3         595         0x80000003 0x008B93
23.1.1.0        3.3.3.3         595         0x80000003 0x00F123

Task 8

r1 

r1#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r1#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/3 ms
r1#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/3 ms
r1#ping 4.4.4.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 2/2/3 ms
r1#ping 12.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 12.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r1#ping 12.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 12.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r1#ping 23.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 23.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r1#ping 23.1.1.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 23.1.1.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r1#ping 34.1.1.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 34.1.1.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/3 ms
r1#ping 34.1.1.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 34.1.1.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/3 ms

r2 

r2#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r2#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/8 ms
r2#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r2#ping 4.4.4.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/3 ms
r2#ping 12.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 12.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r2#ping 12.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 12.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r2#ping 23.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 23.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r2#ping 23.1.1.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 23.1.1.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r2#ping 34.1.1.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 34.1.1.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r2#ping 34.1.1.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 34.1.1.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

r3 

r3#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/3 ms
r3#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r3#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r3#ping 4.4.4.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r3#ping 12.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 12.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r3#ping 12.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 12.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r3#ping 23.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 23.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r3#ping 23.1.1.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 23.1.1.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r3#ping 34.1.1.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 34.1.1.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r3#ping 34.1.1.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 34.1.1.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

r4 

r4#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
r4#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
r4#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r4#ping 4.4.4.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r4#ping 12.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 12.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 2/2/3 ms
r4#ping 12.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 12.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
r4#ping 23.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 23.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/3 ms
r4#ping 23.1.1.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 23.1.1.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r4#ping 34.1.1.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 34.1.1.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
r4#ping 34.1.1.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 34.1.1.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

Task 9

r1 

router bgp 65000
 bgp router-id 1.1.1.1

Task 10

r4 

router bgp 65001
 bgp router-id 4.4.4.4

Task 11

r1 

router bgp 65000
 neighbor 4.4.4.4 remote-as 65001
 neighbor 4.4.4.4 ebgp-multihop 3
 neighbor 4.4.4.4 update-source Loopback0

r4 

router bgp 65001
 neighbor 1.1.1.1 remote-as 65000
 neighbor 1.1.1.1 ebgp-multihop 3
 neighbor 1.1.1.1 update-source Loopback0

Task 12

r1 

r1#show ip bgp nei | i BGP neighbor is|BGP state
BGP neighbor is 4.4.4.4,  remote AS 65001, external link
  BGP state = Established, up for 01:11:12

r4 

r4#show ip bgp nei | i BGP neighbor is|BGP state
BGP neighbor is 1.1.1.1,  remote AS 65000, external link
  BGP state = Established, up for 01:11:12

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