sir, i`m using this lab for testing the BGP SoO .
step-1 CE-1 R5 advertise 126.96.36.199/24 to R1 PE-1
PE-1 reicevd that route on vrf-a address family as an ebgp update
PE-1 add the RD value which is 1:1 and the vpnv4 route would be
1:1:188.8.131.52/24.PE-1 do that in oder to tell the bgp instance on PE-1 if the
exact same route 184.108.40.206/24 is received on PE-1 not to do bgp best path
selection process against these exact two routes and these two routes are
totally different from each others. so, using the RD 1:1 is only used on R1
PE-1 and the RD value has nothing to do if it received on PE-2 side
PE-1 add another extended community which is RT . let`s say vrf-a on PE-1 R1
has export route-target 1000:1 . that is going to be used on the PE-2 side in
oder to tell the PE-2 R4 which is the receiving side which vrf this route is
belongs to .
we have two thing right now,
RD which is used on the sending side only PE-1 R1 to tell him these routes are
different from each others and do not use bgp best path selection process NWLLA
the RT which is used on the receiving side only PE-2 R4 to tell him this route
is belongs to which vrf you have
PE-1 add another extended community called soo value to the vpnv4 route 220.127.116.11/24 soo 1111:1111Extended Community: SoO:1111:1111.
step-6 PE-2 get that route with the RT value 1000:1 and this value is
configured under vrf-c import . so, R4 is going to put that route on vrf-c
step-7 PE-2 advertise that route to CE-2 R6 as an ebgp update.
and now, why do we need to use the soo tag value ?