How to remember BGP best path selection?

How to remember BGP best path selection?

BGP Best Path Algorithm Mnemonic

1. Weight (Highest is better)
2. LOCAL_PREF (Highest is better)
3. Originated Locally.
4. AS_PATH (shortest)
5. ORIGIN Type (IGP is lower than EGP and EGP is lower than Incomplete)
6. MED (lowest is better)
7. Paths (External > Internal)
8. RID (Router ID – lowest is better)

What is best path algorithm?

Best Path selection algorithm makes basic decisions to select the best routes to be installed into the routing table. Currently, BGP is considered to be a standard protocol for the inter-domain information exchange.

What are BGP attributes?

BGP attributes are a confusing array of information carried in a BGP update capable of indicating anything from path preference to various additional pieces of information about a route, either within an autonomous system or outside an autonomous system.

How do you remember a network?

A great place to keep information regarding your new networking contacts is in your phone’s contacts. Along with adding their name, number and email, add notes. If you learned they went to the same university, write it down. If you learn better by physically writing, take notes on the back of the person’s card.

What is the most preferred attribute for BGP?

BGP Best Path Selection Algorithm

• A path with the highest Weight attribute is preferred (other vendors ignore this attribute).
• A path with the highest “local preference” is preferred (usually set to 100).

How BGP is path selection explain in detail?

BGP Attributes. BGP chooses a route to a network based on the attributes of its path. Well-known mandatory: Must be recognized by all BGP routers, present in all BGP updates, and passed on to other BGP routers. For example, AS path, origin, and next hop.

Is EIGRP Still Cisco proprietary?

EIGRP is a routing protocol that is proprietary to Cisco. Although Cisco submitted a portion of EIGRP to the IETF for consideration as a potential standard, the entire protocol has not been accepted as a standard and remains proprietary to Cisco.

Which is the default value for BGP local preference?

Note: A path without LOCAL_PREF is considered to have had the value set with the bgp default local-preference command, or to have a value of 100 by default. Prefer the path that was locally originated via a network or aggregate BGP subcommand or through redistribution from an IGP.

Are there exceptions to the BGP path selection process?

There are some exceptions to the BGP path selection process when you use (advanced) BGP features like confederations, route reflectors, or multipath. Cisco has a detailed list with the BGP best path selection algorithm. I hope this lesson has been useful to understand how BGP selects the best path.

How does a BGP router select the best path?

BGP (Border Gateway Protocol) routers usually receive multiple paths to the same destination. Like how our IGPs (RIP, EIGRP, OSPF) work, we need to select the best path to each destination. IGPs select the path with the lowest metric. For example: RIP selects the path with the lowest hop count.

Which is the best metric for BGP next hop?

The IGP metric to the BGP next hop should be equal to the best-path IGP metric, unless the router is configured for unequal-cost iBGP multipath. BGP inserts up to n most recently received paths from multipath candidates in the IP routing table. The maximum value of n is currently 6.