BGP comprehensive experiment

 

Perform the following experiment in the previous IGP.

Lab requirements:

1. EBGP: R3---R2 R4---R3 R2---R1

2, IBGP: R2---R4 R4---R5 R2---R5

3. All BGP neighbor relationships are established using LO0 for update source (except for R2-R1 ). Use X. X. X.

X as the router-id

4. R3 announcement lo20: 200.200.1.0/24. R5 should select R2.

5. R5 announcement lo20: 200.200.5.0/24

The destination network.

6. R1 announcement lo20: 200.200.4.0/24. This route can only be transmitted within AS200.

Tutorial topology:

 

Configuration points

R1: router bgp 400

No synchronization

Bgp log-neighbor-changes

Network 200.200.4.0

Neighbor 12.1.1.2 remote-as 200

No auto-summary

R2: router bgp 200

No synchronization

Bgp log-neighbor-changes

Neighbor 3.3.3.3 remote-as 100

Neighbor 3.3.3.3 ebgp-multihop 10

Neighbor 3.3.3.3 update-source Loopback10

Neighbor 3.3.3.3 route-map A out

Neighbor 5.5.5 remote-as 200

Neighbor 5.5.5.5 update-source Loopback10

Neighbor 5.5.5.5 next-hop-self

Neighbor 12.1.1.1 remote-as 400

No auto-summary

Ip proute-map A deny 10

Match ip address prefix-list

Route-map A permit 20refix-list A seq 5 permit 200.200.4.0/24

R3: router bgp 100

No synchronization

Bgp log-neighbor-changes

Network 200.200.1.0

Neighbor 2.2.2.2 remote-as 200

Neighbor 2.2.2.2 ebgp-multihop 10

Neighbor 2.2.2.2 update-source Loopback10

Neighbor 4.4.4 remote-as 200

Neighbor 4.4.4 ebgp-multihop 10

Neighbor 4.4.4 update-source Loopback10

No auto-summary

R4: router bgp 200

No synchronization

Bgp log-neighbor-changes

Neighbor 3.3.3.3 remote-as 100

Neighbor 3.3.3.3 ebgp-multihop 10

Neighbor 3.3.3.3 update-source Loopback10

Neighbor 5.5.5 remote-as 200

Neighbor 5.5.5.5 update-source Loopback10

Neighbor 5.5.5.5 next-hop-self

No auto-summary

R5: router bgp 200

No synchronization

Bgp log-neighbor-changes

Network 200.200.5.0

Neighbor 2.2.2.2 remote-as 200

Neighbor 2.2.2.2 update-source Loopback10

Neighbor 2.2.2.2 next-hop-self

Neighbor 4.4.4 remote-as 200

Neighbor 4.4.4 update-source Loopback10

No auto-summary

Test:

View the BGP tables of R3 and R5 respectively:

R5 # show ip bgp

BGP table version is 6, local router ID is 5.5.5.5

Status codes: s suppressed, d damped, h history, * valid,> best, I-internal,

R RIB-failure, S Stale

Origin codes: I-IGP, e-EGP ,? -Incomplete

Network Next Hop Metric LocPrf Weight Path

*> I200.200.1.0 2.2.2.2 0 100 0 100 I

* I 4.4.4.4 0 100 0 100 I

*> I200.200.4.0 2.2.2.2 0 100 0 400 I

*> 200.200.5.0 0.0.0.0 0 32768 I

R3 # show ip bgp

BGP table version is 11, local router ID is 3.3.3.3

Status codes: s suppressed, d damped, h history, * valid,> best, I-internal,

R RIB-failure, S Stale

Origin codes: I-IGP, e-EGP ,? -Incomplete

Network Next Hop Metric LocPrf Weight Path

*> 200.200.1.0 0.0.0.0 0 32768 I

*> 200.200.5.0 2.2.2.2 0 200 I

* 4.4.4.4 0 200 I

Check the R5 route table:

R5 # show ip route

B 200.200.4.0/24 [200/0] via 2.2.2.2, 00:21:33

34.0.0.0/8 is variably subnetted, 2 subnets, 2 masks

D ex 34.1.1.3/32 [170/1657856] via 45.1.1.4, 01:33:48, Serial1/0

[170/1657856] via 54.1.1.4, 01:33:48, FastEthernet0/0

D ex 34.1.1.0/24 [170/1657856] via 45.1.1.4, 01:33:48, Serial1/0

[170/1657856] via 54.1.1.4, 01:33:48, FastEthernet0/0

C 200.200.5.0/24 is directly connected, Loopback20

2.0.0.0/24 is subnetted, 4 subnets

D ex 2.2.1.0 [170/1657856] via 45.1.1.4, 01:33:32, Serial1/0

[170/1657856] via 54.1.1.4, 01:33:32, FastEthernet0/0

D ex 2.2.2.0 [170/1657856] via 45.1.1.4, 01:33:32, Serial1/0

[170/1657856] via 54.1.1.4, 01:33:32, FastEthernet0/0

D ex 2.2.3.0 [170/1657856] via 45.1.1.4, 01:33:32, Serial1/0

[170/1657856] via 54.1.1.4, 01:33:32, FastEthernet0/0

D ex 2.2.4.0 [170/1657856] via 45.1.1.4, 01:33:33, Serial1/0

[170/1657856] via 54.1.1.4, 01:33:33, FastEthernet0/0

3.0.0.0/32 is subnetted, 1 subnets

D ex 3.3.3.3 [170/1657856] via 45.1.1.4, 01:33:33, Serial1/0

[170/1657856] via 54.1.1.4, 01:33:33, FastEthernet0/0

4.0.0.0/24 is subnetted, 1 subnets

D ex 4.4.4.0 [170/1657856] via 45.1.1.4, 03:07:09, Serial1/0

[170/1657856] via 54.1.1.4, 03:07:09, FastEthernet0/0

5.0.0.0/24 is subnetted, 1 subnets

C 5.5.5.0 is directly connected, Loopback10

B 200.200.1.0/24 [200/0] via 2.2.2.2, 00:21:33

54.0.0.0/24 is subnetted, 1 subnets

C 54.1.1.0 is directly connected, FastEthernet0/0

23.0.0.0/24 is subnetted, 1 subnets

D ex 23.1.1.0 [170/1657856] via 45.1.1.4, 01:33:33, Serial1/0

[170/1657856] via 54.1.1.4, 01:33:33, FastEthernet0/0

12.0.0.0/24 is subnetted, 1 subnets

D ex 12.1.1.0 [170/1657856] via 45.1.1.4, 01:33:33, Serial1/0

[170/1657856] via 54.1.1.4, 01:33:33, FastEthernet0/0

45.0.0.0/24 is subnetted, 1 subnets

C 45.1.1.0 is directly connected, Serial1/0

Although both the route table and the BGP table can see the route, but the PING between them still fails, there is no route in IGP.

R5 # ping 200.200.1.3

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 200.200.1.3, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 212/277/344 MS

R5 # ping 200.200.4.1 source 200.200.5.5

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 200.200.4.1, timeout is 2 seconds:

Packet sent with a source address of 200.200.5.5

.....

Success rate is 0 percent (0/5)

View the R1 route table:

R1 # show ip route

C 200.200.4.0/24 is directly connected, Loopback20

1.0.0.0/24 is subnetted, 6 subnets

C 1.1.1.0 is directly connected, Loopback10

C 1.1.2.0 is directly connected, Loopback1

C 1.1.3.0 is directly connected, Loopback2

C 1.1.4.0 is directly connected, Loopback3

C 1.1.11.0 is directly connected, Loopback11

C 1.1.22.0 is directly connected, Loopback12

B 200.200.5.0/24 [20/0] via 12.1.1.2, 00:27:50

B 200.200.1.0/24 [20/0] via 12.1.1.2, 00:39:12

11.0.0.0/24 is subnetted, 1 subnets

C 11.11.11.0 is directly connected, Loopback0

12.0.0.0/24 is subnetted, 1 subnets

C 12.1.1.0 is directly connected, Serial1/1

This article is from the "not interested" blog