Cisco UBR904 - Router - EN Troubleshooting Tips page 43

Table 8 Show Controllers Cable-Modem MAC State Field Descriptions (Continued)
Field
Burst Descriptor:
Interval Usage Code
Modulation Type
Differential Encoding
Preamble Length
FEC Error Correction
FEC Codeword Info Bytes
Scrambler Seed
Maximum Burst Size
Guard Time Size
Last Codeword Length
Scrambler on/off
Network Access
Vendor ID
Auth. Wait Timeout
Reauth. Wait Timeout
Auth. Grace Time
Op. Wait Timeout
Retry Wait Timeout
Description
A compound type/length/value (TLV) encoding that defines, for each type of
upstream usage interval, the physical-layer characteristics that are to be used during
that interval. Each burst descriptor is given an identifying number.
Each upstream transmit burst belongs to a class which is given a number called the
IUC (interval usage code). Bandwidth maps messages (MAP) are used by IUC codes
to allocate upstream time slots. The following types are currently defined:
1. Request: bandwidth request slot
2. Request/Data: bandwidth request or data slot
3. Initial Maintenance: initial link registration contention slot
4. Station Maintenance: link keep-alive slot
5. Short Data Grant: short data burst slot
6. Long Data Grant: long data burst slot
Upstream modulation format. (1 = QPSK; 2 = 16QAM)
Indicates whether or not differential encoding is used. (1 = yes; 2 = no)
Length of the preamble in bits. The value must be an integral number of symbols—a
multiple of 2 for QPSK; a multiple of 4 for 16QAM.
Length of the forward error correction in bytes. The range is 0-10 bytes; a value of 0
implies no forward error correction.
Number of information bytes in the FEC codeword.
15-bit seed value loaded at the beginning of each burst after the register has been
cleared. Not used if scrambler is off.
Maximum number of mini-slots that can be transmitted during this burst type. When
the interval type is Short Data Grant, this value must be greater than 0. If this value is
0, the burst size is limited elsewhere.
Amount of time in symbols between the center of the last symbol of one burst and
the center of the first symbol of the preamble of an immediately following burst in an
upstream transmission from the cable modem to the CMTS.
Indicates whether or not the length of the last codeword is fixed or shortened.
(1 = fixed; 2 = shortened)
Indicates whether or not a scrambler is enabled in the upstream modulator.
(1 = on; 2 = off)
Indicates whether or not the cable modem has access to the HFC network.
Unique identifier specifying the cable modem manufacturer.
The number of seconds the cable modem waits for a reply after sending the
Authorization Request message to the CMTS.
The number of seconds the cable modem waits for a reply after it has sent an
Authorization Request message to the CMTS in response to a reauthorization request
or an Authorization Invalid message from the CMTS.
The number of seconds before the current authorization is set to expire that the grace
timer begins, signaling the cable modem to begin the reauthorization process.
The number of seconds the TEK state machine waits for a reply from the CMTS
after sending its initial Key Request for its SID's keying material.
The number of seconds the TEK state machine waits for a replacement key for this
SID after the TEK grace timer has expired and the request for a replacement key has
been made.
Troubleshooting Tips for the Cisco uBR904 Cable Modem 43
show controllers cable-modem mac