@Network_Eric
sir, i`m using this lab for testing the BGP SoO .
step-1 CE-1 R5 advertise 55.5.5.0/24 to R1 PE-1
step-2
PE-1 reicevd that route on vrf-a address family as an ebgp update
step-3
PE-1 add the RD value which is 1:1 and the vpnv4 route would be
1:1:55.5.5.0/24.PE-1 do that in oder to tell the bgp instance on PE-1 if the
exact same route 55.5.5.0/24 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
step-4
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 .
so
we have two thing right now,
the
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
OMNI OLL
and
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
step-5
PE-1 add another extended community called soo value to the vpnv4 route 55.5.5.0/24 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 ?