When you’re getting ready to go the BSCI Test and make your CCNP certification, certainly one of the largest problems is Studying BGP. BGP is totally various from any protocol you uncovered to gain your CCNA certification, and among the list of variances is usually that BGP makes use of path characteristics to favor just one path more than One more when multiple paths to or from the desired destination exist.
Notice I explained “to or from”. In before absolutely free BGP tutorials, I reviewed the BGP attributes “weight” and “nearby preference”. These attributes are accustomed to favor a single path to your spot about another; one example is, if BGP AS 100 has two paths to some place in AS 200, these two attributes is usually established in AS 100 to favor a single path about A further. But Imagine if AS 100 desires to inform the routers in AS two hundred concerning which path it must use to reach a provided spot in AS one hundred?
That’s the place the BGP attribute “Multi-Exit Discriminator”, or MED, comes in. The MED value is often set in AS 100 to tell AS 200 which route it should really use to reach a given community in AS 100.
Just like lots of BGP characteristics, the MED can be established with a route-map. What you should watch is that there's no “set med” value in route maps. To change the MED of the path, you must change the metric of that path. http://www.bbc.co.uk/search?q=토토사이트 Enable’s say that there are two entry paths for AS two hundred to employ to succeed in Places in AS 100. You wish AS 200 to utilize the one hundred.one.one.0/24 route more than the one hundred.2.two.0/24 path. 1st, detect The 2 paths with two independent ACLs.
R1(config)#access-checklist 22 allow a hundred.one.one.0 0.0.0.255
R1(config)#access-list 23 permit one hundred.two.2.0 0.0.0.255
Future, generate a route-map that assigns a reduced metric to the greater-desirable route.
R1(config)#route-map PREFER_PATH permit ten
R1(config-route-map)#match ip deal with 22
R1(config-route-map)#established metric 100
R1(config-route-map)#route-map PREFER_PATH allow twenty
R1(config-route-map)#match ip handle 23
R1(config-route-map)#established metric 250
Ultimately, implement the route-map towards the neighbor or neighbors.
R1(config-route-map)#router 메이저사이트 bgp a hundred
R1(config-router)#neighbor 22.2.2.two route-map PREFER_PATH out
The crucial element factors to remember is that whilst lots of BGP attributes desire a higher worth, the MED is basically an exterior metric – as well as a decrease metric is preferred, just as Using the protocols you’ve by now analyzed to get paid your CCNA certification.