Configuring a BGP Route Reflector
Context
To ensure the connectivity between IBGP peers within an AS, you need to establish full-mesh connections between the IBGP peers. When there are many IBGP peers, it is costly to establish a fully-meshed network. A route reflector (RR) can solve this problem.
A cluster ID can help prevent routing loops between multiple RRs within a cluster and between clusters. When a cluster has multiple RRs, the same cluster ID must be configured for all the RRs within the cluster.
If full-mesh IBGP connections are established between clients of multiple RRs, route reflection between clients is not required and wastes bandwidth resources. In this case, prohibit route reflection between clients to reduce the network burden.
Within an AS, an RR transmits routing information and forwards traffic. When an RR connects to a large number of clients and non-clients, many CPU resources are consumed if the RR transmits routing information simultaneously. This also reduces route transmission efficiency. To improve route transmission efficiency, prohibit BGP from adding preferred routes to IP routing tables on the RR to enable the RR only to transmit routing information.
Procedure
- Run system-view
The system view is displayed.
- Run bgp { as-number-plain | as-number-dot }
BGP is enabled and the BGP view is displayed.
- Enter the corresponding address family view based on network type to configure BGP devices on networks.
Run ipv4-family unicast
The BGP-IPv4 unicast address family view is displayed.
Run ipv4-family multicast
The BGP-IPv4 multicast address family view is displayed.
Run ipv4-family vpnv4 [ unicast ]
The BGP-VPNv4 address family view is displayed.
Run ipv4-family vpn-instance vpn-instance-name
The BGP-VPN instance IPv4 address family view is displayed.
Run ipv6-family [ unicast ]
The BGP-IPv6 unicast address family view is displayed.
Run ipv6-family vpnv6 [ unicast ]
The BGP-VPNv6 address family view is displayed.
Run ipv6-family vpn-instance vpn-instance-name
The BGP-VPN instance IPv6 address family view is displayed.
- Run peer { group-name | ipv4-address | ipv6-address } reflect-client
An RR and its client are configured.
By default, an RR and its client are not configured.
- (Optional) Run reflector cluster-id cluster-id
A cluster ID is configured for the RR.
By default, each RR uses its router ID as the cluster ID.
- (Optional) Run undo reflect between-clients
Route reflection is prohibited between clients.
By default, route reflection is allowed between clients.
- (Optional) Run routing-table rib-only [ route-policy route-policy-name ]
BGP is prohibited from adding preferred routes to IP routing tables.
By default, BGP adds preferred routes to IP routing tables.
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NOTE: The routing-table rib-only command can be executed only in the BGP view, BGP-IPv4 unicast address family view, and BGP-IPv6 unicast address family view.
- Run commit
The configuration is committed.
Verifying the Configuration
- Run the display bgp group [ group-name ] command to check information about the specified BGP peer group.
- Run the display bgp routing-table [ ipv4-address [ { mask | mask-length } [ longer-prefixes ] ] ] command to check routing information in a BGP routing table.
- Run the display bgp multicast routing-table [ ip-address [ mask-length [ longer-prefixes ] | mask [ longer-prefixes ] ] ] command to check the MBGP routing table.
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