Users Guide

4_OCTET_AS(65)
Extended Next Hop Encoding (5)
Capabilities advertised to neighbor for IPv4 Unicast:
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
4_OCTET_AS(65)
Extended Next Hop Encoding (5)
Prefixes accepted 0, Prefixes advertised 0
Connections established 1; dropped 0
Last reset never
Prefixes ignored due to:
Martian address 0, Our own AS in AS-PATH 0
Invalid Nexthop 0, Invalid AS-PATH length 0
Wellknown community 0, Locally originated 0
Local host: fe80::76e6:e2ff:fef5:b281, Local port: 45926
Foreign host: fe80::76e6:e2ff:fef6:b81, Foreign port: 179
Auto-unnumbered interfaces for BGP
Although the BGP unnumbered feature provides an easier way of configuring BGP, you can use the BGP auto-unnumbered
feature to reduce configuration overhead.
The BGP auto-unnumbered feature works similar to the BGP unnumbered feature. However, with the BGP auto-unnumbered
feature configured, the switch automatically establishes BGP sessions on interfaces that learn the link-local addresses of peer
devices.
Restrictions
All restrictions that are applicable for the BGP unnumbered feature are also applicable for the BGP auto-unnumbered feature.
Prerequisites
● Enable RA advertisement on the required interfaces by using the ipv6 nd send-ra command.
● If you configure RA timers globally and on individual interfaces, interface level RA timers take precedence. In the absence of
interface level RA, global RA timers are applied to all interfaces.
● Configure the global RA timers. Dell EMC Networking recommends that you configure three seconds for the minimum and
four seconds for the maximum RA timer.
● Configure the physical and port channel interfaces to operate in Layer 3 mode by using the no switchport command.
VLAN interfaces do not require this configuration.
● Configure the ipv6 bgp unnumbered {ebgp-template | ibgp-template} command on the required interfaces.
For the BGP auto-unnumbered feature to work, you must specify the type of the template.
● While forming BGP neighborship on an interface, the system uses the corresponding template that is configured under the
ROUTER-BGP-NEIGHBOR mode.
● Template configuration is optional. If there is no template configured, neighborship comes up with default parameters.
● The template type configuration is only used when there is a valid inherit template configuration on the neighbor with the
auto-unnumbered configuration. For example, the ipv6 bgp unnumbered ebgp-template configuration requires the
corresponding inherit ebgp-template configuration.
● An explicit BGP unnumbered configuration using the neighbor interface command brings down any BGP sessions
that are formed using the auto-unnumbered configuration on that interface. The system brings a new session with new
configured parameters.
● If you delete the explicit neighbor configuration which is already configured, the BGP sessions are brought down. If there is
an interface-level auto-unnumbered configuration, the system tries to bring up the BGP session with the unnumbered-auto
neighbor configuration.
Software behavior
● If you delete an interface that is configured as a BGP auto-unnumbered interface which is already in established state, the
established state is brought down.
● If you configure the default interface command on an interface that is configured as a BGP auto-unnumbered
interface which is already in established state, the established state is brought down.
Layer 3
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