Any one can explain why routers can send traffic with different RD and same RT?

[wfqk]

Hi Any one can explain why routers can send traffic among them with different RD and same RT? Since RD decide different routing table, why different routing table can send traffic to each other? 

[blau grana]

Hi,

RD does not decide which vrf prefixes will be imported.

RD is used to convert IPv4 prefix into VPNv4 prefix(if we are talking about IPv4). This is very useful if different customers use same IP ranges but thanks to RD prefixes will still be unique inside MPLS cloud.

RTs are extended communities and these decide which prefixes will be imported into respective VRFs.

It doesn't really matter if you have same or different RD/RT if you know what you are doing. You need to make sure that RT exported in one site will be imported in other site and vice versa to be able to ping from one site to another via MPLS cloud.

[wfqk]

Great! Thank you. 

One vrf can only own one RD and several RT. It looks like that RD can be considered as a special sign for the vrf, right? If RD is just a sign, can we change it? for example, after vrf is defined as ABC and MPLS begin to run, if i want to change RD value from 100:1 into 200:2 and keep vrf name ABC unchanged, do you think it would cause some issue to its network?