dslreports logo

    All FAQs Site FAQ DSL FAQ Cable Tech About DSL Distance DSL Hurdles »»


how-to block ads

This page displays various QPSK forward and reverse path statistics:

    The first set of values are in a table containing data statistics for the QPSK forward path. Each row is for a separate data channel and contains seven (7) numbers:
      Ctrl is the value of the channel's control register. Bit 0 set (0x01) indicates that the channel is enabled.VPI is the value of the channel's ATM hardware filter.VCI is the value of the channel's ATM hardware filter.Off is the channel's hardware filter's offset into the data stream.DMA is the value of the channels DMA status register. This is a hexadecimal number. The bits are defined as:
        0x4: READ PEND - PTV stream read pending flag. This indicates if PowerTV is trying to read data from the dma channel.0x2: PKT AVAIL - Hardware data available flag. This indicates that the DMA layer has indicated a packet is in the receive buffer.0x1: OVERFLOW (or initially, channel DISABLED) - This indicates that the DMS layer has detected a DMA buffer overflow and has stopped the channel.
      Ovfl is a counter of the number of DMA overflows that have occurred on the channel. This number should be very low. Internally, this number is kept as a 32-bit value, but since it should always be a very low value, only the value of the lowest 16-bits is displayed. If the true value is greater than 65535 (16-bits), the low 16-bits value is displayed followed by a plus (+) sign to indicate that the number is really much higher than the displayed value.Packets is the number of of individual data packets received. This typically represents a single Ethernet Frame (1500 bytes max).
        CA is the channel containing conditional access data.Broadcast is the channel containing data being broadcast to multiple set-tops.DNCS is the channel which the Digital Network Control System uses to communicate with the set-top.DAVIC is the channel which is used for the DAVIC connection.PassThru is the channel which 1-way pass-through messages are received on.Spare is a spare DMA channel.

    The second set of values are in a table containing statistics for the QPSK reverse path.

      Each row is for a separate transmission type and contains two (2) numbers:
        Okay is the number of packets transmitted for the type that were sent without error.Errors is the number of transmit packets aborted with a hardware error or time out error.
          Slotted Aloha values are for slotted-aloha transmissions. These are typically DAVIC command and control messages or small App messages.TDMA values are for Time Division Multiple Access transmissions (used by a constant bandwidth connection).Reservation values are for reserved slot transmissions. Most application messages will be sent this way.Ranging values are for the power level / ranging calibration transmissions performed during sign-on.

      Expand got feedback?

      by Corvus See Profile
      last modified: 2005-02-15 20:53:34