if only Local preference configure what will happen to return traffic

[TangoAlfa]

Hi All

In BGP if I only configure Local preference for out bound traffic what will happen to return traffic. will it cause asymmetric routing, to avoide that is it mandatory to configure MED or AS path?

Thanks

[MHM Cisco World]

Yes you are correct' 

If you control outbound and NOT config Inbound then there is chance asymmetric routing will happen.

[Flavio Miranda · Accepted solution]

Hi

  If you have more than one ISP, this is true.  But for single homed setup,dont make sense.

And  with AS PATH prepending you can change how the internet see you, which means, this is not valid only to your ISP but any AS out there . While MED is valid only to the neighboard AS, which probably is your ISP.

[MHM Cisco World]

I REWRITE SHORT ANSWER BECAUSE 

I need to run lab check asymmetric traffic with two cases 

1- dual homed same ISP <<- here I need to check I think inside same ISP there is possibility that asymmetric traffic is eliminated' I will share how this happens.

2-dual homed diff ISP <<- here sure asymmetric traffic happened 

[TangoAlfa]

Ok