BGP Origin Code Attribute

 

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MED or Multi Exit Discriminator is non-transitive attribute and is used to discriminate between two entry point of AS

The lower MED value is preferred

In our topology, both R5 and R6 will generate the same prefixes through BGP to R7

10.1.65.0/30

10.1.65.4/30

10.1.65.8/30

As we can see R7 is using R5 to route to these prefixes because the router-id is lower for R5 than R6

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Using Origin-code attribute modify R5  so R7 route through R6 to reach these prefixes

As we know  if Weight, Local preference, Originate and AS-PATH attribute for a route are the same BGP will compare the origin code attribute

Origin Code is well know mandatory attribute

where

IGP is preferred over EGP over incomplete

we has these routes  advertised through the network statement in the BGP process on R5

so I we change the origin to incomplete i.e redistribute them this will change their origin code to incomplete and therefore R7 will prefer R6 routes

This can be seen from the BGP table on R7 below

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