The value of tBgpPeerLocalAddress specifies the local IP address
to be used by this peer.
If set to 0.0.0.0, then use a (non-0.0.0.0) Peer Group Local Address,
or a (non-0.0.0.0) global Local Address. If both are zero then find the
local address by querying the closest interface to the peer address
from the routing table.