Setting up an BGP Neighborship Connection

In the example diagram above, an eBGP neighborship is set up between ER-L (AS 64512) and ER-R (AS 65000) which allows the neighbors to exchange routing information. In this case, ER-L will advertise the 198.51.100.x/26 networks to ER-R.
Follow the steps below to configure the BGP protocol on both routers:
CLI: Access the Command Line Interface on ER-L.You can do this using the CLI button in the GUI or by using a program such as PuTTY.
1. Enter configuration mode.
configure
2. Define the BGP Autonomous System (AS) number and the Router ID.
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set protocols bgp 64512 parameters router-id 203.0.113.1
3. Define the IP address and AS number used by the BGP neighbor.
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set protocols bgp 64512 neighbor 192.0.2.1 remote-as 65000
4. As the neighbors are not directly connected, enable ebgp-multihop and additional options such as soft-reconfiguration.
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set protocols bgp 64512 neighbor 192.0.2.1 ebgp-multihop 255 set protocols bgp 64512 neighbor 192.0.2.1 soft-reconfiguration inbound
NOTE:The value set in the ebgp-multihop... command can be customized.
5. Create blackhole routes for the 198.51.100.x/26 networks that should be advertised into BGP.
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set protocols static route 198.51.100.0/26 blackhole set protocols static route 198.51.100.64/26 blackhole set protocols static route 198.51.100.128/26 blackhole set protocols static route 198.51.100.192/26 blackhole
6. Advertise the 198.51.100.x/26 routes into BGP by using the network statement.
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set protocols bgp 64512 network 198.51.100.0/26 set protocols bgp 64512 network 198.51.100.64/26 set protocols bgp 64512 network 198.51.100.128/26 set protocols bgp 64512 network 198.51.100.192/26
NOTE:The network... statements in BGP must match the routes present in the routing table.
7. Commit the changes and save the configuration.
commit ; save
CLI: Access the Command Line Interface on ER-R.You can do this using the CLI button in the GUI or by using a program such as PuTTY.
1. Enter configuration mode.
configure
2. Define the BGP Autonomous System (AS) number and the Router ID.
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set protocols bgp 65000 parameters router-id 192.0.2.1
3. Define the IP address and AS number used by the BGP neighbor.
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set protocols bgp 65000 neighbor 203.0.113.1 remote-as 64512
4. As the neighbors are not directly connected, enable ebgp-multihop and additional options such as soft-reconfiguration.
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set protocols bgp 65000 neighbor 203.0.113.1 ebgp-multihop 255 set protocols bgp 65000 neighbor 203.0.113.1 soft-reconfiguration inbound
NOTE:The value set in the ebgp-multihop... command can be customized.
5. Commit the changes and save the configuration.
commit ; save
The BGP neighborship and advertised/received routes can be verified with the following commands:
show ip bgp summary show ip bgp show ip bgp neighbors 192.0.2.1 advertised-routes show ip bgp neighbors 192.0.2.1 received-routes
Additional BGP Options
There are many other BGP options and additional features that can be configured when using BGP. Some of the more popular options are:
- Route-Maps
- Prefix-Lists
- BGP Communities
- Peer Groups
- Route Reflectors
- Confederations
See the output below for a list of available commands (output may differ between firmware versions):
set protocols bgp 64512 ? Possible completions: address-family BGP address-family parameters aggregate-address BGP aggregate network dampening Enable route-flap dampening maximum-paths BGP multipaths neighbor BGP neighbor network BGP network parameters BGP parameters peer-group BGP peer-group redistribute Redistribute routes from other protocols into BGP timers BGP protocol timers set protocols bgp 64512 parameters ? Possible completions: always-compare-med Always compare MEDs from different neighbors bestpath Default bestpath selection mechanism cluster-id Route-reflector cluster-id confederation AS confederation parameters dampening Enable route-flap dampening default BGP defaults deterministic-med Compare MEDs between different peers in the same AS distance Administratives distances for BGP routes enforce-first-as Require first AS in the path to match peer's AS graceful-restart Graceful restart capability parameters log-neighbor-changes Log neighbor up/down changes and reset reason no-client-to-client-reflection Disable client to client route reflection no-fast-external-failover Disable immediate sesison reset if peer's connected link goes down router-id BGP router id scan-time BGP route scanner interval set protocols bgp 64512 neighbor 192.0.2.1 ? Possible completions: address-family Parameters relating to IPv4 or IPv6 routes advertisement-interval Minimum interval for sending routing updates allowas-in Accept a route that contains the local-AS in the as-path attribute-unchanged BGP attributes are sent unchanged capability Advertise capabilities to this neighbor default-originate Send default route to this neighbor description Description for this neighbor disable-capability-negotiation Disable capability negotiation with this neighbor disable-send-community Disable sending community attributes to this neighbor distribute-list Access-list to filter route updates to/from this neighbor ebgp-multihop Allow this EBGP neighbor to not be on a directly connected network fall-over Fall-over detection filter-list As-path-list to filter route updates to/from this neighbor local-as Local AS number maximum-prefix Maximum number of prefixes to accept from this neighbor nexthop-self Nexthop for routes sent to this neighbor to be the local router no-activate Disable the Address Family for this Neighbor override-capability Ignore capability negotiation with specified neighbor passive Do not initiate a session with this neighbor password BGP MD5 password peer-group IPv4 peer group for this peer port Neighbor's BGP port prefix-list Prefix-list to filter route updates to/from this neighbor remote-as Neighbor BGP AS number [REQUIRED] remove-private-as Remove private AS numbers from AS path in outbound route updates route-map Route-map to filter route updates to/from this neighbor route-reflector-client Neighbor as a route reflector client route-server-client Neighbor is route server client shutdown Administratively shut down neighbor soft-reconfiguration Soft reconfiguration for neighbor strict-capability-match Enable strict capability negotiation timers Neighbor timers unsuppress-map Route-map to selectively unsuppress suppressed routes update-source Source IP of routing updates weight Default weight for routes from this neighbor