Any time you’re making ready to pass the BSCI Test and get paid your CCNP certification, considered one of the most significant problems is learning BGP. BGP is completely distinctive from any protocol you acquired to receive your CCNA certification, and one of the variances is BGP takes advantage of path characteristics to favor a person route above One more when a number of paths to or from the spot exist.
Discover I mentioned “to or from”. In earlier free BGP tutorials, I talked over the BGP attributes “pounds” and “area desire”. These characteristics are used to favor one particular path to some location about another; for example, if BGP AS 100 has two paths to some destination in AS 200, these two attributes can be established in AS 100 to favor 1 path more than An additional. But Let's say AS one hundred desires to tell the routers in AS 200 as to which path it really should use to achieve a given place in AS 100?
That’s wherever the BGP attribute “Multi-Exit Discriminator”, or MED, comes in. The MED worth http://query.nytimes.com/search/sitesearch/?action=click&contentCollection®ion=TopBar&WT.nav=searchWidget&module=SearchSubmit&pgtype=Homepage#/토토사이트 is usually set in AS one hundred to tell AS 200 which path it must use to reach a provided community in AS 100.
As with lots of BGP attributes, the MED can be established which has a route-map. What you should look at is that there's no “set med” value in route maps. To alter the MED of the route, you need to change the metric of that route. Allow’s say that there are two entry paths for AS 200 to implement to succeed in Places in AS one hundred. You'd like AS two hundred to utilize the a hundred.one.1.0/24 path around the a hundred.2.two.0/24 path. Very first, discover the two paths with two different ACLs.
R1(config)#obtain-list 22 permit 100.one.one.0 0.0.0.255
R1(config)#entry-listing 23 permit a hundred.two.two.0 0.0.0.255
Next, produce a route-map that assigns a reduce metric to the more-desirable route.
R1(config)#route-map PREFER_PATH permit 사설사이트 10
R1(config-route-map)#match ip address 22
R1(config-route-map)#established metric a hundred
R1(config-route-map)#route-map PREFER_PATH allow 20
R1(config-route-map)#match ip address 23
R1(config-route-map)#established metric 250
Ultimately, utilize the route-map to the neighbor or neighbors.
R1(config-route-map)#router bgp a hundred
R1(config-router)#neighbor 22.two.2.two route-map PREFER_PATH out
The important thing factors to bear in mind is the fact when numerous BGP attributes favor a better benefit, the MED is basically an external metric – and also a lower metric is preferred, just as While using the protocols you’ve by now researched to make your CCNA certification.