Advanced BGP Configuration

ENARSI (300-410) BGP (BORDER GATEWAY PROTOCOL)
Weight

Prefer the path with the highest weight. This is a value that is local to the router and it’s Cisco proprietary. The default value is 0 for all routes that are not originated by the local router. You can learn how it works in the BGP weight attribute lesson.
Local Preference

The local preference is used within an autonomous system and exchanged between iBGP routers. We prefer the path with the highest local preference. The default value is 100. To learn more, take a look at the BGP local preference attribute lesson.
Originate

Prefer the path that the local router originated. In the BGP table, you will see next hop 0.0.0.0. You can get a path in the BGP table through the BGP network command, aggregation, or redistribution. A BGP router will prefer routes that it installed into BGP itself over a route that another router installed in BGP.
AS path length

Prefer the path with the shortest AS path length. For example, AS path 1 2 3 is preferred over AS path 1 2 3 4 5. You can learn more about AS path length here.
Origin code

Prefer the lowest origin code. There are three origin codes:

IGP
EGP
INCOMPLETE

IGP is lower than EGP and EGP is lower than INCOMPLETE. You can learn how it works in the origin code lesson.
MED

Prefer the path with the lowest MED. The MED is exchanged between autonomous systems. For a detailed explanation, take a look at the MED lesson.
eBGP path over iBGP path

Prefer eBGP (external BGP) over iBGP (internal BGP) paths.
Shortest IGP path to BGP next hop

Prefer the path within the autonomous system with the lowest IGP metric to the BGP next hop.
Oldest Path

Prefer the path that we received first, in other words, the oldest path.
Router ID

Prefer the path with the lowest BGP neighbor router ID. The router ID is based on the highest IP address. If you have a loopback interface, then the IP address on the loopback will be used. The router ID can also be manually configured.