TASK 2.5 - cosmetic as-path question


I used:

Rack1R6#show ip as-path-access-list 
AS path access list 54
    permit _54$
AS path access list 60
    permit _60$

but SG suggests that we should use ^54$ for routes originating from AS54.

Anyway I think that _54$ is more appropriate (^54$ is more specific, not only routes must be originated in as54, but also cannot traverse any other as), but in this specific configuration it doesn't matter - AS54 is directly connected anyway.

Do you think that both solutions would be accepted?



  • I would think that as BB1 and BB3 are directly connected and in AS52, that you would never expect 54 to be far away in the as-path. 


    If the question did not state 'from BB1' or 'from BB3' then _54$ would be the better

  • And to add to the cosmetic nature of this point why bother with the second AS Path Access List as all we need to do is specify AS54 with the implict understanding that if the source AS isn't it change the community?


    ip as-path access-list 54 permit _54$


    route-map FROM_BB1 permit 10

     match as-path 54

     set community 54:1

    route-map FROM_BB1 permit 20

     set community 60:1

    And so on...
  • I think for this task, both regexs are acceptable. But I tend to agree more with jdr.

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