Users Guide

BGP 1427
the NEXT_HOP to one of its own global addresses before forwarding routes
from an external peer with a link local address (or the implementation must
do this automatically).
A primary consideration in using link-local addresses is the user interface.
With IPv4 addresses and global IPv6 addresses, the user interface simply
identifies the neighbor by IP address:
router bgp 1
neighbor 10.1.1.1 remote-as 100
neighbor 10.1.1.1 advertisement-interval 10
neighbor 2001:db8::1 remote-as 200
neighbor 2001:db8::1 advertisement-interval 20
Because two neighbors on different links may have the same link local
address, the address itself may not uniquely identify a neighbor, nor does the
link local address identify the interface where control packets should be sent
to the neighbor. The interface must also be specified.
Dell EMC Networking uses the same MAC address for all routing interfaces
on a router and, thus, has the same link local address on each interface. If a
user were to try to configure two parallel adjacencies between two Dell EMC
Networking routers and wanted to use link local peering, the peers would have
the same link local address.
Dell EMC Networking BGP uses the interface parameter to the neighbor
command to identify a unique auto-configured link local address as shown in
the following examples:
router bgp 1
neighbor fe80::1 interface vlan 10 remote-as 100
neighbor fe80::1 interface vlan 10 advertisement-interval 10
neighbor fe80::1 interface vlan 20 remote-as 200
BGP Dynamic Neighbor Peering
This capability allows peering with BGP neighbors to be dynamically
established when BGP connection requests are received from a configured IP
address range. Dynamic neighbor peering avoids the need for explicit
configuration of the neighbor by the administrator when it is acceptable to
establish peering with a neighbor irrespective of their specific IP address. This
capability is especially useful when deploying BGP in data centers where