BGP Best Path Selection Algorithm

[dhikra-marghli8]

Hello

I know well if we have several paths to the destination, we will BGP Best Path Selection Algorithm  . 

my question ,

in which case we were obliged to use :  BGP Best Path Selection Algorithm   and  and don't use anything else ?? 

i wait a answer from expert service provider !!

thanks

[dhikra-marghli8]

any reply , please !!

[MHM Cisco World]

whenever you use BGP you mandatory use BGP best path selection
there is no case you use bgp without algorithm to select best path.
MHM

[M02@rt37]

Hello @dhikra-marghli8 

You typically use the BGP Best Path Selection algorithm when dealing with multiple paths to a destination and need to determine the best route based on various attributes. BGP considers factors like AS path, origin code, next hop, local preference, and more to make this decision. Mandatory !

[MHM Cisco World]

I can say Yes and NO 
BGP with multi path 
BGP with Single path 

both 
share the first point of Best path selection 

• Paths for which the NEXT_HOP is inaccessible.

  Be sure that there is an Interior Gateway Protocol (IGP) route to the NEXT_HOP that is associated with the path.

any path with inaccessible NEXT-hop not select as best path even if it only path

but sure when we run BGP we use best path selection 
MHM

[M02@rt37]

In both BGP scenarios, whether using multipath or single path, the first point of the Best Path Selection Algorithm involves ensuring that the NEXT_HOP is accessible. It's a fundamental criterion in BGP best path selection. If the NEXT_HOP is inaccessible, the path is not considered a viable option, regardless of whether it's the only path or one of multiple paths. BGP inherently employs its best path selection algorithm to determine the optimal route based on various attributes, ensuring efficient and reliable routing in different network configurations.

[dhikra-marghli8]

is there another scenario apart  wil use in the case multiple path in  BGP best path selection ? 

[M02@rt37 · Accepted solution]

Best path selecton algorithm is an integral part of the protocol, and it is always active when multiple paths are available for a destination. Even if you have only one path configured, the BGP decision process evaluates the attributes of that single path according to the algorithm... but sure when we run BGP we use best path selection...Yes !

https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html

[MHM Cisco World]

And we can disable best path when we use one path?

Or it run auto when we use bgp?

MHM