Typically, T1/E1 equipment at a site relies on the physical availability of the T1/E1 ports to determine the uplink capacity (that is, for ATM IMA or MLPPP groups). When a failure in the access link between the 7705 SAR and the associated T1/E1 equipment is detected, notification of the failure is propagated by the PW status signaling using one of two methods — label withdrawal or TLV (see LDP Status Signaling). In addition, the PW failure must also be propagated to the devices attached to the T1/E1 equipment. The propagation method depends on the type of port used by the access circuit (ATM, T1/E1 TDM, or Ethernet) and is described below.