HPE 5800 Series Configuration Manual page 182

Figure 59 MED attribute
D = 9.0.0.0
Next_hop = 2.1.1.1
MED = 0
Router A
D = 9.0.0.0
Next_hop = 3.1.1.1
MED = 100
AS 10
In general, BGP compares MEDs of routes received from the same AS only. You can also use
the compare-different-as-med command to force BGP to compare MED values of routes
received from different ASs.
•
LOCAL_PREF
The LOCAL_PREF attribute is exchanged between IBGP peers only, and is not advertised to
any other AS. It indicates the priority of a BGP router.
LOCAL_PREF is used to determine the best route for traffic leaving the local AS. When a BGP
router obtains multiple routes to the same destination but with different next hops from several
IBGP peers, it considers the route with the highest LOCAL_PREF value as the best route. As
shown in Figure
according to LOCAL_PREF.
MED = 0
Router B
2.1.1.1
EBGP IBGP
IBGP
EBGP IBGP
3.1.1.1
Router C
MED = 100
60, traffic from AS 20 to AS 10 travels through Router C that is selected
171
9.0.0.0
Router D
AS 20