Explanation:
RD (Route Distinguisher):
Used to identify different VPN instances on PEs, and its main function is to implement VPAddress multiplexing between N instances, together with the IP address to form 12 BytesVPNv4 address. RD has 64 bits and IP address is 32 bits, which together constitute 96 bits of VPNV4 address.
VPNV4 address 12 bytes = 8 bytesRD +4 bytes IPV4 address
RD is carried along with routes in BGP It is sent to the peer end in an Update message.
RD does not have the ability to select routes and does not affect the sending and receiving of routes. RD is used to distinguish local VRFs and is valid locally.
RT (Route Target)
RT is an important attribute carried by VPNv4 routes. It determines the sending, receiving and filtering of VPN routes. PEs rely on the RT attribute to distinguish routes between different VPNs. The length is also 64 bits.
when from VWhen exporting VPN routes in the RF table, use Export RT marks VPN routes.
When importing a VPN route into the VRF table, only the RT tag and any Import in the VRF table Only the routes that match the RT will be imported into the VRF table.
