If you’re planning to go the BSCI exam and earn your CCNP certification, certainly one of the largest problems is Discovering BGP. BGP is totally diverse from any protocol you figured out to get paid your CCNA certification, and one of many differences is the fact BGP employs path characteristics to favor a person route more than Yet another when a number of paths to or from the vacation spot exist.
Observe I mentioned “to or from”. In earlier free of charge BGP tutorials, I talked about the BGP attributes “bodyweight” and “regional desire”. These characteristics are utilized to favor one route to a desired destination in excess of A different; for instance, if BGP AS a hundred has two paths to your desired destination in AS two hundred, these two attributes could be established in AS 100 to favor just one path above An additional. But Let's say AS a hundred would like to tell the routers in AS 200 as to which path it should really use to achieve a offered location in AS one hundred?
That’s exactly where the BGP attribute “Multi-Exit Discriminator”, or MED, is available in. The MED price may be established in AS a hundred to tell AS two hundred which path it should really use to succeed in a presented community in AS a hundred.
Just like many BGP characteristics, the MED can be established using a route-map. What you should http://query.nytimes.com/search/sitesearch/?action=click&contentCollection®ion=TopBar&WT.nav=searchWidget&module=SearchSubmit&pgtype=Homepage#/토토사이트 look at is that there's no “set med” value in route maps. To change the MED of the path, you have to change the metric of that path. Allow’s say there are two entry paths for AS two hundred to use to achieve Places in AS one hundred. You need AS two hundred to use the a hundred.1.1.0/24 route over the a hundred.2.two.0/24 path. First, recognize The 2 paths with two different ACLs.
R1(config)#access-listing 22 permit 100.1.1.0 먹튀검증사이트 0.0.0.255
R1(config)#access-record 23 permit a hundred.two.2.0 0.0.0.255
Upcoming, write a route-map that assigns a decreased metric to the more-desirable path.
R1(config)#route-map PREFER_PATH allow ten
R1(config-route-map)#match ip deal with 22
R1(config-route-map)#established metric one hundred
R1(config-route-map)#route-map PREFER_PATH permit twenty
R1(config-route-map)#match ip handle 23
R1(config-route-map)#established metric 250
Eventually, utilize the route-map into the neighbor or neighbors.
R1(config-route-map)#router bgp 100
R1(config-router)#neighbor 22.two.two.two route-map PREFER_PATH out
The crucial element factors to keep in mind is always that while several BGP characteristics prefer an increased value, the MED is largely an external metric – along with a decreased metric is favored, just as with the protocols you’ve previously examined to gain your CCNA certification.