Cisco CCNP Certification: The BGP Weight Attribute
- October 18, 2017
- Posted by: marlenedubois
- Category: CPR Training
When you’re studying for the CCNP certification, especially the BSCI exam, you must gain a solid understanding of BGP. BGP isn’t just one of the biggest topics on the BSCI exam, the idea’s one of the largest. BGP features a great many details of which must be mastered for BSCI success, along with those of you with one eye on the CCIE must learn the fundamentals of BGP right now in order to build on those fundamentals at a later time.
Path attributes are a unique feature of BGP. With Indoor gateway protocols such as OSPF along with EIGRP, administrative distance is actually used as a tiebreaker when two routes to the same destination had different next-hop IP addresses however the same prefix length. BGP uses path attributes to make This kind of choice.
The first attribute considered by BGP is actually weight. Weight is actually a Cisco-proprietary BGP attribute, so if you’re working in a multivendor environment you should work with another attribute to influence path selection.
The weight attribute is actually significant only to the router on which the idea is actually changed. If you set a higher weight for a particular route in order to give the idea preference (a higher weight is actually preferred over a lower one), of which weight is actually not advertised to various other routers.
BGP uses categories such as “transitive”, “non-transitive”, “mandatory”, along with “optional” to classify attributes. Since weight is actually a locally significant Cisco-proprietary attribute, the idea does not all into any of these categories.
The weight can be changed on one particular route via a route-map, or the idea can be set for a different weight for all routes received coming from a given neighbor. To change the weight for all incoming routes, use the “weight” option with the neighbor command after forming the BGP peer relationships.
R2(config)#router bgp 100
R2(config-router)#neighbor 18.104.22.168 remote-as 10
R2(config-router)#neighbor 22.214.171.124 weight 0
Learning all of the BGP attributes, as well as when to use them, can seem an overwhelming task when you first start studying for your BSCI along with CCNP exams. Break This kind of task down into little parts, learn one attribute at a time, along with soon you’ll possess the BGP attributes mastered.