BGP route reflector

[mautez_mah]

dear Gents 
I have learned BGP RR as CCIE R&S and I found this point I did not understand it so can anyone explain it to me plz in another way 

(The use of set clauses in outbound route maps can modify attributes and possibly create routing loops. To avoid this behavior, most set clauses of outbound route maps are ignored for routes reflected to iBGP peers. The only set clause of an outbound route map that is acted upon is the set ip next-hop clause.)

form Cisco website  i don't understand what is attributes will not be applied in BGP 

[Sergey Lisitsin]

@mautez_mah ,

The route reflector in BGP usally doesn't lie in the actual traffic flow path, so it doesn't need to modify route attributes that it reflects. It merely acts as an exchange point between other iBGP peers, so it needs to preserve original attributes.

[mautez_mah]

Ok, and if we modify it will cause a loop, (set clauses of outbound route maps are ignored) we can't apply ??

[Sergey Lisitsin]

It may cause a loop at certain conditions. But it doesn't guarantee one. Because as I said, the route reflector might be not in the traffic path, but if you modify the attributes on it, it will influence the path selection.