Preferred I over E & E over ?. It implies that the route was

injected into BGP as I (IGP), E (EGP) or ? (incomplete information).

Allows an AS to tell a

neighboring AS the best path to forward packets into the first AS. Lowest is

preferred.

Locally injected routes

(routes injected using network command) are better than iBGP/eBGP learned.

It is the number of ASNs in the AS Path. Lowest is preferred.

It is a numeric value set and communicated within a

single AS for the purpose of choosing best route for all routers in that AS to

reach a certain network. Highest is preferred

It is a numeric value set by a router when receiving updates to

influence the route for a prefix. It is not advertised to any BGP peers.