Refer to the Exhibit.
You are the administrator of AS 65000. In the exhibit, there are four links between your network (AS 65000) and your upstream provider (AS 65001).
You have an export policy on all of your routers to advertise your routes such that:
Router A: MED 100, AS Path (65000), Origin 1
Router B: MED 100, AS Path (65000 65000), Origin 0
Router C: MED 50, AS Path (65000 65000), Origin 1
Router D: MED 50, AS Path (65000), Origin 0
Through which link will traffic from the Web server enter your network (AS 65000)?
A.
Router A
B.
Router B
C.
Router C
D.
Router D
Router D
Explanation
When choosing a bgp path, 3 of the tests in order are
1-Prefer the path with the shortest AS path length
2-Prefer the path with the lowest origin value
3-Prefer the path with the lowest MED value.
Going by this, Answers B and C do not come into play because there is no local pref value assigned, So the next test is AS Path for which these will lose as they are advertising two as paths in the route advertisement.
Next is Router A and D, Both which tie on the AS path, Next is Router D has the lowest origin value so Router D is chosen.
The MED does not come into play here as the tie is broken at the Origin test.
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