We have a customer MPLS network in which IPSEC/ GRE tunnels are established between CE routers of two locations. The WAN link is a 6 Mbps Ethernet link. All the outbound and inbound traffic is sent through the same tunnel interface. While the peak output rate (show interface) shown in the physical interface is close to 6Mbps, its always about 500-800K less (around 4.9 to 5.2M) in the tunnel interface. Customer wants to know why there is BW capping in the tunnel interface.
Do we have a technical explanation for the difference in displayed output rate, between the physical and tunnel interfaces?