BGP Auto-Discovered Neighbor (BGP Unnumbered Peering)
This section describes BGP auto-discovered neighbor (also known as BGP unnumbered peering) feature and its configuration on the QFX5220, QFX5230, QFX5240, and QFX5241 Switches.
Overview
The QFX Series Switches in EVPN-VXLAN data center fabrics use BGP auto-discovered neighbors to simplify IPv6 underlay configuration. The switches automatically discover and establish peering sessions with directly connected neighbors using link-local IPv6 addresses. You can use this feature to configure BGP peering by interface rather than by specifying remote or local neighbor IP addresses. Using the IPv6 Neighbor Discovery Protocol to automatically discover link-local addresses of directly connected neighbors, you can simplify deployment and reduce misconfiguration risk.
QFX Series Switches in the EVPN-VXLAN data center fabric support both Internal Border Gateway Protocol (IBGP) for the overlay routing and External Border Gateway Protocol (EBGP) for overlay and underlay routing within spine-and-leaf architecture fabrics. For more information about BGP, see Understanding BGP.
Configure BGP Auto-Discovered Neighbor
Using this feature, you can configure BGP neighbors by interface or interface range, eliminating the need to manually define per-peer IP addresses for each BGP session. It expands your fabric without reconfiguring individual peer addresses, reducing operational complexity, and provisioning errors.
To enable BGP auto-discovered neighbor using IPv6 Neighbor Discovery on a device:
Configure the fabric-facing interfaces with both
inetandinet6address families:set interfaces interface-range to-spine member interface-name-1 set interfaces interface-range to-spine member interface-name-2 set interfaces interface-range to-spine unit 0 family inet address IPv4-address set interfaces interface-range to-spine unit 0 family inet6 IPv6-address
Configure the local autonomous number (AS) number:
set routing-options autonomous-system AS-number
Define an AS list to restrict which remote AS numbers are accepted:
set policy-options as-list a-list members start-end
It allows you to define an allowed AS number list so that only neighbors with matching AS numbers can establish BGP sessions, maintaining security without static neighbor definitions.
Enable IPv6 router advertisements (RAs) on the fabric-facing interfaces:
set protocols router-advertisement interface interface-name1 max-advertisement-interval maximum-interval-number set protocols router-advertisement interface interface-name1 min-advertisement-interval minimum-interval-number
Configure the BGP group with dynamic neighbor autodiscovery:
set protocols bgp group autodisc type external set protocols bgp group autodisc family inet unicast extended-nexthop set protocols bgp group autodisc family inet6 unicast set protocols bgp group autodisc dynamic-neighbor ndp peer-auto-discovery family inet6 ipv6-nd set protocols bgp group autodisc dynamic-neighbor ndp peer-auto-discovery interface interface-name1 set protocols bgp group autodisc peer-as-list a-list
Verify BGP Auto-Discovered Neighbor Configuration
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To check whether the fabric interfaces are up and running:
show interfaces interface-name show interfaces terse
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To verify that all fabric interfaces are sending and receiving IPv6 router advertisements:
show ipv6 router-advertisement
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To verify that the fabric devices have learned the MAC-to-link-local address bindings of all directly attached IPv6 neighbors using IPv6 neighbor discovery:
show ipv6 neighbors
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To verify that all fabric devices have established BGP peering sessions to the directly connected neighbors:
show bgp summary auto-discovered show bgp neighbor auto-discovered
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To verify that all nodes are advertising their loopback address while learning the loopback address of other nodes:
show route protocol bgp