Implementing Basic BGP
R5#configure terminalR5(config)#router bgp 6500
R5(config-router)#neighbor 10.1.45.4 remote-as 5500
R5(config-router)#do show ip bgp summary
BGP router identifier 10.1.45.5, local AS number 6500
BGP table version is 1, main routing table version 1
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
10.1.45.4 4 5500 0 0 0 0 0 never Active
Configure R4
R4#configure terminal
R4(config)#router bgp 5500
R4(config-router)#neighbor 10.1.45.5 remote-as 6500
*Mar 1 00:17:21.003: %BGP-5-ADJCHANGE: neighbor 10.1.45.5 Up
R4(config-router)#do show ip bgp summary
BGP router identifier 4.4.4.4, local AS number 5500
BGP table version is 1, main routing table version 1
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
10.1.45.5 4 6500 4 4 1 0 0 00:01:33 0
### How To Established Neighborship Between R1 and R4
Create Loopback Interfaces and Add those into OSPF
R1#Configure terminal
R1(config)#interface loopback 0
R1(config-if)#ip address 1.1.1.1 255.255.255.255
R1(config-if)#exit
R1(config)#router ospf 1
R1(config-router)#network 1.1.1.1 0.0.0.0 area 0
R1(config-router)#end
R1#show ip route ospf | inc 4.4.4.4
O 4.4.4.4 [110/129] via 10.1.13.3, 00:29:18, Serial1/0
R4#Configure terminal
R4(config)#interface loopback 0
R4(config-if)#ip address 4.4.4.4 255.255.255.255
R4(config-if)#exit
R4(config)#router ospf 1
R4(config-router)#network 4.4.4.4 0.0.0.0 area 0
R4(config-router)#end
R4#show ip route ospf | inc 1.1.1.1
O 1.1.1.1 [110/129] via 10.1.34.3, 00:28:49, Serial1/1
### Configure BGP
R4#configure terminal
R4(config)#router bgp 5500
R4(config-router)#neighbor 1.1.1.1 remote-as 5500
R4(config-router)#neighbor 1.1.1.1 update-source loopback 0
*Mar 1 00:38:21.699: %BGP-5-ADJCHANGE: neighbor 1.1.1.1 Up
R1#configure terminal
R1(config)#router bgp 5500
R1(config-router)#neighbor 4.4.4.4 remote-as 5500
R1(config-router)#neighbor 4.4.4.4 update-source loopback 0
*Mar 1 00:45:39.115: %BGP-5-ADJCHANGE: neighbor 4.4.4.4 Up
### Two Ways To Get Network Into BGP:
*Network Command
*Redistribution
### Redistribute Routes From R5
R5#show ip interface brief | include Loopback
Loopback1 200.1.1.1 YES manual up up
Loopback2 200.1.2.1 YES manual up up
Loopback3 200.1.3.1 YES manual up up
Loopback4 200.1.4.1 YES manual up up
Loopback5 200.1.5.1 YES manual up up
Loopback6 200.1.6.1 YES manual up up
Loopback50 50.1.1.1 YES manual up up
Advertise 50.1.1.0/24 Network Using Network Command
R5#configure terminal
R5(config)#router bgp 6500
R5(config)#do show ip interface brief | inc 50.1.1.1
Loopback50 50.1.1.1 YES manual up up
R5(config)#do show ip interface loopback 50 | inc Internet address
Internet address is 50.1.1.1/24
R5(config-router)#network 50.1.1.0 mask 255.255.255.0
R5(config-router)#^Z
R5#show ip bgp
BGP table version is 2, local router ID is 10.1.45.5
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
*> 50.1.1.0/24 0.0.0.0 0 32768 i
###Verify On R4
R4#show ip route 50.1.1.1
Routing entry for 50.1.1.0/24
Known via "bgp 5500", distance 20, metric 0
Tag 6500, type external
Last update from 10.1.45.5 00:06:00 ago
Routing Descriptor Blocks:
* 10.1.45.5, from 10.1.45.5, 00:06:00 ago
Route metric is 0, traffic share count is 1
AS Hops 1
Route tag 6500
R4#show ip route | include 50.1.1.0
B 50.1.1.0 [20/0] via 10.1.45.5, 00:07:56
### Redistribute Into BGP (Redistribute Only 200.1.1-4.0/24 Routes)
R5(config)#access-list 20 permit 200.1.1.0
R5(config)#access-list 20 permit 200.1.2.0
R5(config)#access-list 20 permit 200.1.3.0
R5(config)#access-list 20 permit 200.1.4.0
Create Route-Map
R5(config)#route-map FILTER-20
R5(config-route-map)#match ip address 20
R5(config-route-map)#^Z
R5#show route-map
route-map FILTER-20, permit, sequence 10
Match clauses:
ip address (access-lists): 20
Set clauses:
Policy routing matches: 0 packets, 0 bytes
R5#show access-lists 20
Standard IP access list 20
10 permit 200.1.1.0
30 permit 200.1.3.0
20 permit 200.1.2.0
40 permit 200.1.4.0
R5#configure terminal
R5(config)#router bgp 6500
R5(config-router)#redistribute connected route-map FILTER-20
(Just Wait BGP Is Very Slow Protocol)
R5#show ip bgp
BGP table version is 6, local router ID is 10.1.45.5
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
*> 50.1.1.0/24 0.0.0.0 0 32768 i
*> 200.1.1.0 0.0.0.0 0 32768 ?
*> 200.1.2.0 0.0.0.0 0 32768 ?
*> 200.1.3.0 0.0.0.0 0 32768 ?
*> 200.1.4.0 0.0.0.0 0 32768 ?
Verify On R4
R4#show ip bgp
BGP table version is 6, local router ID is 4.4.4.4
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
*> 50.1.1.0/24 10.1.45.5 0 0 6500 i
*> 200.1.1.0 10.1.45.5 0 0 6500 ?
*> 200.1.2.0 10.1.45.5 0 0 6500 ?
*> 200.1.3.0 10.1.45.5 0 0 6500 ?
*> 200.1.4.0 10.1.45.5 0 0 6500 ?
R4#show ip route | include 200.1
B 200.1.4.0/24 [20/0] via 10.1.45.5, 00:04:07
B 200.1.1.0/24 [20/0] via 10.1.45.5, 00:04:07
B 200.1.2.0/24 [20/0] via 10.1.45.5, 00:04:07
B 200.1.3.0/24 [20/0] via 10.1.45.5, 00:04:07
### How To Get This BGP Networks into R1 (How To Fix It)
* BGP Synchronization
-Do not use or advertise a route learned via IBGP until the same
route has been learned from the internal routing protocol
Verify R1
R1#show ip bgp
BGP table version is 1, local router ID is 1.1.1.1
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
* i50.1.1.0/24 10.1.45.5 0 100 0 6500 i
* i200.1.1.0 10.1.45.5 0 100 0 6500 ?
* i200.1.2.0 10.1.45.5 0 100 0 6500 ?
* i200.1.3.0 10.1.45.5 0 100 0 6500 ?
* i200.1.4.0 10.1.45.5 0 100 0 6500 ?
R1#show ip route bgp
(Nothing)
### Fix It
R1#configure terminal
R1(config)#router bgp 5500
R1(config-router)#no synchronization
R4#configure terminal
R4(config)#router bgp 5500
R4(config-router)#no synchronization
On R1 Next-Hop Is 10.1.45.5 (R5) R1 does not know how to reach it
R1#ping 10.1.45.5
.....
Success rate is 0 percent (0/5)
### BGP Next-Hop Processing:
- For EBGP peers: Change next hop address on advertised routes
- For IBGP peers: Do not change next hop address on advertised routes
R4#configure terminal
R4(config)#router bgp 5500
R4(config-router)#neighbor 1.1.1.1 next-hop-self
Verify R1
R1#show ip bgp
BGP table version is 6, local router ID is 1.1.1.1
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
*>i50.1.1.0/24 4.4.4.4 0 100 0 6500 i
*>i200.1.1.0 4.4.4.4 0 100 0 6500 ?
*>i200.1.2.0 4.4.4.4 0 100 0 6500 ?
*>i200.1.3.0 4.4.4.4 0 100 0 6500 ?
*>i200.1.4.0 4.4.4.4 0 100 0 6500 ?
R1#show ip route bgp
B 200.1.4.0/24 [200/0] via 4.4.4.4, 00:01:27
50.0.0.0/24 is subnetted, 1 subnets
B 50.1.1.0 [200/0] via 4.4.4.4, 00:01:27
B 200.1.1.0/24 [200/0] via 4.4.4.4, 00:01:27
B 200.1.2.0/24 [200/0] via 4.4.4.4, 00:01:27
B 200.1.3.0/24 [200/0] via 4.4.4.4, 00:01:27
Now R1 Knows How to Reach 4.4.4.4 and Syncronization is Turn Off
Done!!!
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