Ubiquiti - Setting up an BGP Neighborship Connection

Page / - last modified by Jean Franco on 2024/06/09 20:48

Setting up an BGP Neighborship Connection

last modified by Jean Franco

on 2024/06/09 20:48

Table of Contents

Additional BGP Options

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