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Example for Configuring Basic BGP Functions

Example for Configuring Basic BGP Functions

Mar 03, 2023

Network Requirement

As shown in Figure. 1, BGP runs on all the switches.

An EBGP connection is established between Switch A and Switch B, and IBGP fullmesh connections are established between Switch B, Switch C, and Switch D. 

Configure IBGP connections between Switch B, Switch C, and Switch D.

Configure an EBGP connection between Switch A and Switch B.

 Figure 1. BGP configuration

Procedure

This section describes the steps of how to configure basic BGP functions on SwitchA, SwitchB, SwitchC and SwitchD.

Switch A

Step1         Configure the VLANs and VLAN interfaces.

admin@SwitchA# set vlans vlan-id 10 l3-interface vlan10
admin@SwitchA# set vlans vlan-id 20 l3-interface vlan20
admin@SwitchA# set interface gigabit-ethernet te-1/1/1 family ethernet-switching native-vlan-id 10
admin@SwitchA# set interface gigabit-ethernet te-1/1/2 family ethernet-switching native-vlan-id 20
admin@SwitchA# set l3-interface vlan-interface vlan10 address 192.168.10.1 prefix-length 24
admin@SwitchA# set l3-interface vlan-interface vlan20 address 192.168.20.1 prefix-length 24

Step2        Configure an EBGP connection.

admin@SwitchA# set protocols bgp router-id 1.1.1.1
admin@SwitchA# set protocols bgp local-as 100
admin@SwitchA# set protocols bgp neighbor 192.168.20.2 remote-as 200
admin@SwitchA# set protocols bgp ebgp-requires-policy false

Step3        Enable IP routing.

admin@SwitchA# set ip routing enable true

Step4         Commit the configurations.

admin@SwitchA# commit

Switch B

Step1         Configure the VLANs and VLAN interfaces.

admin@SwitchB# set vlans vlan-id 20 l3-interface vlan20
admin@SwitchB# set vlans vlan-id 30 l3-interface vlan30
admin@SwitchB# set vlans vlan-id 40 l3-interface vlan40
admin@SwitchB# set interface gigabit-ethernet te-1/1/2 family ethernet-switching native-vlan-id 20
admin@SwitchB# set interface gigabit-ethernet te-1/1/3 family ethernet-switching native-vlan-id 30
admin@SwitchB# set interface gigabit-ethernet te-1/1/4 family ethernet-switching native-vlan-id 40
admin@SwitchB# set l3-interface vlan-interface vlan20 address 192.168.20.2 prefix-length 24
admin@SwitchB# set l3-interface vlan-interface vlan30 address 192.168.30.1 prefix-length 24
admin@SwitchB# set l3-interface vlan-interface vlan40 address 192.168.40.1 prefix-length 24

Step2        Configure EBGP and IBGP connections.

admin@SwitchB# set protocols bgp router-id 2.2.2.2
admin@SwitchB# set protocols bgp local-as 200
admin@SwitchB# set protocols bgp neighbor 192.168.20.1 remote-as 100
admin@SwitchB# set protocols bgp neighbor 192.168.30.2 remote-as 200
admin@SwitchB# set protocols bgp neighbor 192.168.40.2 remote-as 200
admin@SwitchB# set protocols bgp ebgp-requires-policy false

Step3        Enable IP routing.

admin@SwitchB# set ip routing enable true

Step4         Commit the configurations.

admin@SwitchB# commit

Switch C

Step1         Configure the VLANs and VLAN interfaces.

admin@SwitchC# set vlans vlan-id 30 l3-interface vlan30
admin@SwitchC# set vlans vlan-id 50 l3-interface vlan50
admin@SwitchC# set interface gigabit-ethernet te-1/1/4 family ethernet-switching native-vlan-id 30
admin@SwitchC# set interface gigabit-ethernet te-1/1/5 family ethernet-switching native-vlan-id 50
admin@SwitchC# set l3-interface vlan-interface vlan30 address 192.168.30.2 prefix-length 24
admin@SwitchC# set l3-interface vlan-interface vlan50 address 192.168.50.1 prefix-length 24

Step2        Configure the IBGP connection.

admin@SwitchC# set protocols bgp router-id 3.3.3.3
admin@SwitchC# set protocols bgp local-as 200
admin@SwitchC# set protocols bgp neighbor 192.168.30.1 remote-as 200
admin@SwitchC# set protocols bgp neighbor 192.168.50.2 remote-as 200

Step3        Enable IP routing.

admin@SwitchC# set ip routing enable true

Step4         Commit the configurations.

admin@SwitchC# commit

Switch D

Step1         Configure the VLANs and VLAN interfaces.

admin@SwitchD# set vlans vlan-id 40 l3-interface vlan40
admin@SwitchD# set vlans vlan-id 50 l3-interface vlan50
admin@SwitchD# set interface gigabit-ethernet te-1/1/4 family ethernet-switching native-vlan-id 40
admin@SwitchD# set interface gigabit-ethernet te-1/1/5 family ethernet-switching native-vlan-id 50
admin@SwitchD# set l3-interface vlan-interface vlan40 address 192.168.40.2 prefix-length 24
admin@SwitchD# set l3-interface vlan-interface vlan50 address 192.168.50.2 prefix-length 24

Step2        Configure the IBGP connection.

admin@SwitchD# set protocols bgp router-id 4.4.4.4
admin@SwitchD# set protocols bgp local-as 200
admin@SwitchD# set protocols bgp neighbor 192.168.40.1 remote-as 200
admin@SwitchD# set protocols bgp neighbor 192.168.50.1 remote-as 200

Step3        Enable IP routing.

admin@SwitchD# set ip routing enable true

Step4         Commit the configurations.

admin@SwitchD# commit

Viewing BGP Peer Status on Switch B

admin@SwitchB# run show bgp neighbor
BGP neighbor on vlan20: 192.168.20.1, remote AS 100, local AS 200, external link
  BGP version 4, remote router ID 1.1.1.1, local router ID 2.2.2.2
  BGP state = Idle
  Last read 00:15:06, Last write never
  Hold time is 180, keepalive interval is 60 seconds
  Graceful restart information:
    Local GR Mode: Helper*
    Remote GR Mode: NotApplicable
    R bit: False
    Timers:
      Configured Restart Time(sec): 120
      Received Restart Time(sec): 0
  Message statistics:
    Inq depth is 0
    Outq depth is 0
                         Sent       Rcvd
    Opens:                  0          0
    Notifications:          0          0
    Updates:                0          0
    Keepalives:             0          0
    Route Refresh:          0          0
    Capability:             0          0
    Total:                  0          0
  Minimum time between advertisement runs is 0 seconds

 For address family: IPv4 Unicast
  Not part of any update group
  Community attribute sent to this neighbor(all)
  0 accepted prefixes

  Connections established 0; dropped 0
  Last reset 00:15:06,  Waiting for Peer IPv6 LLA
BGP Connect Retry Timer in Seconds: 120
Read thread: off  Write thread: off  FD used: -1

BGP neighbor is 192.168.30.2, remote AS 200, local AS 200, internal link
 Administratively shut down
  BGP version 4, remote router ID 3.3.3.3, local router ID 2.2.2.2
  BGP state = Idle
  Last read 00:15:06, Last write never
  Hold time is 180, keepalive interval is 60 seconds
  Graceful restart information:
    Local GR Mode: Helper*
    Remote GR Mode: NotApplicable
    R bit: False
    Timers:
      Configured Restart Time(sec): 120
      Received Restart Time(sec): 0
  Message statistics:
    Inq depth is 0
    Outq depth is 0
                         Sent       Rcvd
    Opens:                  0          0
    Notifications:          0          0
    Updates:                0          0
    Keepalives:             0          0
    Route Refresh:          0          0
    Capability:             0          0
    Total:                  0          0
  Minimum time between advertisement runs is 600 seconds

 For address family: IPv4 Unicast
  Not part of any update group
  Advertise bestpath per AS via addpath
  Override ASNs in outbound updates if aspath equals remote-as
  Community attribute sent to this neighbor(all)
  0 accepted prefixes

  Connections established 0; dropped 0
  Last reset 00:15:06,  No AFI/SAFI activated for peer
  External BGP neighbor may be up to 255 hops away.
BGP Connect Retry Timer in Seconds: 111
Peer Authentication Enabled
Read thread: off  Write thread: off  FD used: -1

BGP neighbor is 192.168.40.2, remote AS 200, local AS 200, internal link
  BGP version 4, remote router ID 4.4.4.4, local router ID 2.2.2.2
  BGP state = Active
  Last read 00:15:06, Last write never
  Hold time is 180, keepalive interval is 60 seconds
  Graceful restart information:
    Local GR Mode: Helper*
    Remote GR Mode: NotApplicable
    R bit: False
    Timers:
      Configured Restart Time(sec): 120
      Received Restart Time(sec): 0
  Message statistics:
    Inq depth is 0
    Outq depth is 0
                         Sent       Rcvd
    Opens:                  0          0
    Notifications:          0          0
    Updates:                0          0
    Keepalives:             0          0
    Route Refresh:          0          0
    Capability:             0          0
    Total:                  0          0
  Minimum time between advertisement runs is 0 seconds

 For address family: IPv4 Unicast
  Not part of any update group
  Advertise bestpath per AS via addpath
  Override ASNs in outbound updates if aspath equals remote-as
  Community attribute sent to this neighbor(all)
  0 accepted prefixes

  Connections established 0; dropped 0
  Last reset 00:15:06,  No AFI/SAFI activated for peer
  External BGP neighbor may be up to 255 hops away.
BGP Connect Retry Timer in Seconds: 111
Peer Authentication Enabled
Read thread: off  Write thread: off  FD used: -1

Configuring Switch A to Advertise Route 192.168.10.0/24

admin@SwitchA# set protocols bgp ipv4-unicast network 192.168.10.0/24
admin@SwitchA# commit


View the BGP routing table of Switch B:

admin@SwitchB# run show bgp
show bgp ipv4 unicast
=====================
BGP table version is 2, local router ID is 4.4.4.4, vrf id 0
Default local pref 100, local AS 200
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 192.168.10.0/24
                    192.168.20.1             0             100 32768 i

Displayed  1 routes and 1 total paths


show bgp ipv6 unicast
=====================
No BGP prefixes displayed, 0 exist


View the BGP routing table of Switch C:

admin@SwitchC# run show bgp
show bgp ipv4 unicast
=====================
BGP table version is 2, local router ID is 3.3.3.3, vrf id 0
Default local pref 100, local AS 200
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 192.168.10.0/24
                    192.168.20.1             0             100 32768 i

Displayed  1 routes and 1 total paths


show bgp ipv6 unicast
=====================
No BGP prefixes displayed, 0 exist

The preceding command output display that the route to destination 192.168.10.0/24 becomes invalid because the next hop address of this route is unreachable. 

Configuring Switch B to Advertise a Connected Route

admin@SwitchB# set protocols bgp ipv4-unicast redistribute connected
admin@SwitchB# commit

Ping 192.168.10.1 on Switch C:

admin@SwitchC# run ping 192.168.10.1
PING 192.168.10.1 (192.168.10.1) 56(84) bytes of data.
64 bytes from 192.168.10.1: icmp_req=1 ttl=63 time=4.68 ms
64 bytes from 192.168.10.1: icmp_req=2 ttl=63 time=4.46 ms
64 bytes from 192.168.10.1: icmp_req=3 ttl=63 time=5.35 ms
64 bytes from 192.168.10.1: icmp_req=4 ttl=63 time=4.52 ms
64 bytes from 192.168.10.1: icmp_req=5 ttl=63 time=4.51 ms 
192.168.10.1 ping statistics —
5 packets transmitted, 5 received, 0% packet loss, time 4017ms
rtt min/avg/max/mdev = 4.460/4.709/5.358/0.338 ms

View the BGP routing table of Switch C:

admin@SwitchC# run show bgp
show bgp ipv4 unicast
=====================
BGP table version is 2, local router ID is 3.3.3.3, vrf id 0
Default local pref 100, local AS 200
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 192.168.10.0/24
                    192.168.20.1             0             100 32768 i
*> 192.168.40.0/24
                    192.168.30.1             0             100 32768 i
   192.168.30.0/24
                    192.168.30.1             0             100 32768 i
*> 192.168.10.0/24
                    192.168.30.1             0             100 32768 i

Displayed  4 routes and 4 total paths


show bgp ipv6 unicast
=====================
No BGP prefixes displayed, 0 exist










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