Specifications

DOCSIS 1.1 for Cisco uBR905 and Cisco uBR925 Cable Access Routers and Cisco CVA122 Cable Voice Adapters

Command Reference

Cisco IOS Release 12.2(15)CZ

Interval Usage Code Each upstream transmit burst belongs to a class that is given a number

called the interval usage code (IUC). Bandwidth MAP messages 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 keepalive slot

5. Short Data Grant: short data burst slot

6. Long Data Grant: long data burst slot

Modulation Type Upstream modulation format. (1 = QPSK; 2 = QAM-16)

Differential Encoding Indicates whether or not differential encoding is used. (1 = yes; 2 = no)

Preamble Length Length of the preamble in bits. This value must be an integral number of

symbols—a multiple of 2 for QPSK; a multiple of 4 for QAM-16.

FEC Error Correction Length of the forward error correction in bytes. The range is 0 to 10 bytes;

a value of 0 implies no forward error correction.

FEC Codeword Info

Bytes

Number of information bytes in the FEC codeword.

Scrambler Seed 15-bit seed value loaded at the beginning of each burst after the register

has been cleared. Not used if scrambler is off.

Maximum Burst Size 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.

Guard Time Size Amount of time in symbols between the center of the last symbol of a

burst and the center of the first symbol of the preamble of an immediately

following burst in an upstream transmission from the router to the CMTS.

Last Codeword Length Whether or not the length of the last codeword is fixed or shortened. (1 =

fixed; 2 = shortened)

Scrambler on/off Indicates whether or not a scrambler is enabled in the upstream modulator.

(1 = on; 2 = off)

Network Access Whether or not the router has access to the HFC network.

Concatenation Whether DOCSIS 1.1 concatenation is enabled or disabled.

Maximum CPEs Maximum number of CPEs supported for this cable modem.

Vendor ID Unique identifier specifying the CM manufacturer.

Auth. Wait Timeout Number of seconds the router waits for a reply after sending the

Authorization Request message to the CMTS.

Reauth. Wait Timeout Number of seconds the router 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.

Table 9 show controller cable-modem mac state Field Descriptions (continued)

Field Description