The Topology above shows a simple EBGP peers, part of my study journey towards CCIE Routing and Switching certificate.
no matter how big your topology is, EBGP peering basically work the same way
Router #1 contains the configs below:
where the loopback interfaces are used as update source, this type of configs will require IGP route to each loopback interface in order for the routers to be able to
* Adding the Command #ebgp multihop in order to increase the TTL to be more than 1 and also to cancel the connected check option between two BGP neighbors that requires two routers to be in the same subnet [ connected ] in order to be peers.
=======================================================================
Router #1 Configs :
interface Loopback0
ip address 100.100.100.100 255.255.255.0
!
interface Loopback100
ip address 50.50.50.1 255.255.255.0
!
interface FastEthernet0/0
ip address 10.0.0.1 255.255.255.0
speed 100
full-duplex
!
interface FastEthernet0/1
ip address 13.13.13.1 255.255.255.0
duplex auto
speed auto
!
router bgp 100
no synchronization
bgp log-neighbor-changes
network 50.50.50.0 mask 255.255.255.0
neighbor 3.3.3.3 remote-as 90
neighbor 3.3.3.3 ebgp-multihop 2
neighbor 3.3.3.3 update-source Loopback0
neighbor 5.5.5.5 remote-as 200
neighbor 5.5.5.5 ebgp-multihop 2
neighbor 5.5.5.5 update-source Loopback0
no auto-summary
!
ip route 3.3.3.0 255.255.255.0 13.13.13.3
ip route 5.5.5.0 255.255.255.0 10.0.0.2
=====================================================================
Router #2 Configs
!
interface Loopback0
ip address 5.5.5.5 255.255.255.0
!
interface Loopback20
ip address 20.20.20.20 255.255.255.0
!
interface FastEthernet0/0
ip address 10.0.0.2 255.255.255.0
speed 100
full-duplex
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
router bgp 200
no synchronization
bgp log-neighbor-changes
network 20.20.20.0 mask 255.255.255.0
neighbor 100.100.100.100 remote-as 100
neighbor 100.100.100.100 ebgp-multihop 2
neighbor 100.100.100.100 update-source Loopback0
no auto-summary
!
ip route 100.100.100.0 255.255.255.0 10.0.0.1
!
====================================================================
Router #3 Configs
interface Loopback0
ip address 3.3.3.3 255.255.255.0
interface Loopback90
ip address 9.9.9.9 255.255.255.0
interface FastEthernet0/0
no ip address
shutdown
duplex auto
speed auto
interface FastEthernet0/1
ip address 13.13.13.3 255.255.255.0
duplex auto
speed auto
!
router bgp 90
no synchronization
bgp log-neighbor-changes
network 9.9.9.0 mask 255.255.255.0
neighbor 100.100.100.100 remote-as 100
neighbor 100.100.100.100 ebgp-multihop 2
neighbor 100.100.100.100 update-source Loopback0
no auto-summary
!
ip route 100.100.100.0 255.255.255.0 13.13.13.1
Now let's verify the configurations :
R1#show ip bgp
BGP table version is 4, local router ID is 100.100.100.100
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
*> 9.9.9.0/24 3.3.3.3 0 0 90 i
*> 20.20.20.0/24 5.5.5.5 0 0 200 i
*> 50.50.50.0/24 0.0.0.0 0 32768 i
===========================================================
R1#show ip bgp summary
BGP router identifier 100.100.100.100, local AS number 100
BGP table version is 4, main routing table version 4
3 network entries using 360 bytes of memory
3 path entries using 156 bytes of memory
4/3 BGP path/bestpath attribute entries using 496 bytes of memory
2 BGP AS-PATH entries using 48 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
Bitfield cache entries: current 1 (at peak 1) using 32 bytes of memory
BGP using 1092 total bytes of memory
BGP activity 3/0 prefixes, 3/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
3.3.3.3 4 90 8 10 4 0 0 00:04:04 1
5.5.5.5 4 200 8 10 4 0 0 00:04:07 1
Hope this was useful!
Samer R. Saleem
No comments:
Post a Comment