BGP question - again

[carl_townshend]

hi all

i configured 2 bgp neighbours, both in different AS's

i thought if I route comes from an external AS, it should show as "e" when doing a show ip bgp ? they are currently showing as "i" for internal

cheers

[cadet alain]

Hi,

e means EGP which was the successor of BGP and which is deprecated for a long time now.

So wheter the prefix is advertised by an iBGP or eBGP peer the origin code can only be i ( advertised via a network command) or ? ( redistributed). The only way to get an e code is to set it in a route-map.

Regards.

Alain

[Vasileios Bouloukos MSc, ITIL, CCIE]

Hi Carl,

These value reflect the BGP attribure named "origin"

This is the fifth attribute checked to the BGP path selection algorithm.

"Prefer the path with the lowest origin type.

Note: IGP ( i )  is lower than Exterior Gateway Protocol (EGP), and EGP is lower than INCOMPLETE (?)."

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.shtml

The only way to have the e origin is with route map as Cadet mentioned above. This could be needed if you want to use the origin bgp attribute to define the preference of the BGP routes.

Hope that helps!

Vasilis

[ringoranger]

Hi Carl,

One thing you can check is the admin distance. If you see 20 it's eBGP and 200 for iBGP. you can see this from the show ip route command.