HPE FlexNetwork HSR6800 Configuration Manual page 198

When a BGP speaker advertises a self-originated route to a BGP peer, it sets the address of the sending
interface as the NEXT_HOP.
When a BGP speaker sends a received route to an EBGP peer, it sets the address of the sending
interface as the NEXT_HOP.
When a BGP speaker sends a route received from an EBGP peer to an IBGP peer, it does not modify the
NEXT_HOP attribute. If load balancing is configured, BGP modifies the NEXT_HOP attribute for the equal-cost
routes. For information about load balancing, see
Figure 60 NEXT_HOP attribute
•
MED (Multi-Exit-Discriminator)
BGP advertises the MED attribute between two neighboring ASs, each of which does not
advertise the attribute to any other AS.
Similar to metrics used by IGP, MED is used to determine the best route for traffic going into an
AS. When a BGP router obtains multiple routes to the same destination but with different next
hops from different EBGP peers, it considers the route with the smallest MED value the best
route given that other conditions are the same. As shown in
20 travels through Router B that is selected according to MED.
"BGP load balancing."
186
Figure 61, traffic from AS 10 to AS