Whenever you’re preparing to go the BSCI Examination and generate your CCNP certification, among the most significant difficulties is Discovering BGP. BGP is completely distinctive from any protocol you uncovered to generate your CCNA certification, and one of several distinctions is the fact BGP employs path attributes to favor one path about An additional when numerous paths to or from a location exist.
See I claimed “to or from”. In previously no cost BGP tutorials, I mentioned the BGP characteristics “body weight” and “area desire”. These characteristics are used to favor one particular route into a desired destination in excess of One more; by way of example, if BGP AS 100 has two paths to your desired destination in AS two hundred, both of these attributes is often set in AS a hundred to favor a person path in excess of A further. But Let's say AS 100 wants to tell the routers in AS 200 concerning which path it need to use to reach a supplied spot in AS one hundred?
That’s the place the BGP attribute “Multi-Exit Discriminator”, or MED, comes in. The MED value is often established in AS 100 to inform AS 200 which route it should use to achieve a provided network in AS 100.
Just like many BGP characteristics, the MED is usually established by using a route-map. What you have to check out is that there's no “set med” price in route maps. To alter the MED of the route, you should change the metric of that route. Enable’s say that there are two entry paths for AS 200 to use to achieve Locations in AS one hundred. You want AS two hundred to make use of the one hundred.1.1.0/24 route in excess of the one hundred.two.2.0/24 path. 1st, recognize The 2 Additional reading paths with two separate ACLs.
R1(config)#accessibility-listing 22 allow a hundred.1.one.0 0.0.0.255
R1(config)#accessibility-listing 23 allow one hundred.2.2.0 0.0.0.255
Next, write a route-map that assigns a reduce metric to the greater-appealing path.
R1(config)#route-map PREFER_PATH allow 10
R1(config-route-map)#match ip http://www.bbc.co.uk/search?q=토토사이트 handle 22
R1(config-route-map)#established metric a hundred
R1(config-route-map)#route-map PREFER_PATH permit 20
R1(config-route-map)#match ip address 23
R1(config-route-map)#set metric 250
At last, utilize the route-map for the neighbor or neighbors.
R1(config-route-map)#router bgp one hundred
R1(config-router)#neighbor 22.two.2.2 route-map PREFER_PATH out
The crucial element factors to remember is the fact although several BGP attributes like an increased price, the MED is basically an external metric – as well as a reduced metric is chosen, just as Together with the protocols you’ve currently analyzed to gain your CCNA certification.