BGP is Probably the most elaborate subject areas you’ll study when pursuing your CCNP, if not one of the most elaborate. I know from particular encounter that After i was earning my CCNP, BGP is The subject that gave me the most problems initially. One thing I continue to keep reminding now’s CCNP candidates about, nevertheless, is the fact that no Cisco engineering is unachievable to grasp if you merely break it down and comprehend the basics before you start trying to be aware of the greater complicated configurations.
BGP attributes are a single this sort of topic. You’ve obtained nicely-identified obligatory, effectively-acknowledged discretionary, transitive, and non-transitive. Then you’ve got each individual BGP attribute to recall, as well as order wherein BGP considers characteristics, and what attributes even are… and a ton far more! As with any other Cisco subject, we have to walk prior to we will run. Let’s take a look at what characteristics are and the things they do in BGP.
BGP characteristics are very similar to what metrics are to OSPF, RIP, IGRP, and EIGRP. You received’t see them listed within a routing desk, but characteristics are what BGP considers When selecting the ideal route to the spot when various legitimate (loop-free of charge) paths exist.
When BGP has to determine among such paths, there is an order by which BGP considers http://www.thefreedictionary.com/토토사이트 the path characteristics. For success over the CCNP tests, you need to know this order. BGP looks at path characteristics in this buy:
Maximum excess weight (Cisco-proprietary BGP worth)
Best local choice (LOCAL_PREF)
Like domestically originated route.
Shortest AS_PATH is most well-liked.
Pick out route with least expensive origin code. Inner paths are most well-liked over external paths, and exterior paths are 토토사이트 favored over paths having an origin of “incomplete”.
Least expensive multi-exit discriminator (MED)
Exterior BGP routes favored above Inside BGP routes.
If no exterior route, choose route with most affordable IGP Expense to the following-hop router for iBGP.
Opt for most recent route.
Opt for lowest BGP RID (Router ID).
Should you don’t determine what these values are, or how they’re configured, don’t panic! The following a number of portions of this BGP tutorial will explain it all. So devote some time studying this get, and in part II of the free BGP tutorial, we’ll take a look at Each individual of such values intimately. Keep studying!