According to this cisco document (https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html), shortest AS_PATH is the #4 algorithm in the sequence to evaluate, out of 13 in the list, after BGP picks the first valid path from the available list. It says:
"BGP assigns the first valid path as the current best path. BGP then compares the best path with the next path in the list, until BGP reaches the end of the list of valid paths."
I'm listing the algorithms it listed for convenience:
- Weight: Highest
- Local Preference: Highest
- Network or Aggregate: Locally originated
- AS_PATH: Shortest
- Origin type: Lowest origin number
- Multi-exit discriminator (MED): Lowest
- eBGP over iBGP:
- IGP metric: Shortest IGP path to BGP next hop
- Multiple paths: Highest number of multiple path in the routing table
- External paths: Oldest (whatever received first)
- Router ID: Lowest
- Cluster list: Minimum cluster list length
- Neighbor address: Lowest
However, according to the most of the video tutorials out there the 'shortest AS_PATH' algorithm seems BGP’s the only best path selection algorithm to the destination.
Am I catching it correct?