Frame Relay - CIR & Frame Marking
Access Rate: rate R of the access link between source router (customer) and edge FR switch (provider); 64Kbps < R < 1,544Kbps
Typically, many VCs (one per destination router) multiplexed on the same access trunk; each VC has own CIR
Edge FR switch measures traffic rate for each VC; it marks
(ie DE <= 1) frames which exceed CIR (these may be later dropped)