Superhub 5 Channel Processor

Supported Modems

This processor is only known to work with the Virgin Media Superhub 5.

Fetching the Data

The Superhub 5 exposes a REST API on its webserver at /rest/v1. There are 3 endpoints which interest us here:

/rest/v1/cablemodem/downstream
/rest/v1/cablemodem/upstream
/rest/v1/cablemodem/serviceflows

The Superhub 5 runs at 192.168.0.1 in router mode and 192.168.100.1 in modem mode.

Interpreting the Data

JSON data is returned from each GET request.

Downstream

.downstream.channels contains an array of downstream channels. Each channel is made up of:

channelId - Channel ID
frequency - Frequench in hertz
power - Power in dBmV
modulation - Channel modulation (map below)
snr - Signal to Noise ratio in dB
rxMer - Signal to Noise ratio in dB (used by DOCSIS 3.1 channels)
correctedErrors - Count of corrected codewords
uncorrectedErrors - Count of uncorrectable codewords
lockStatus - (Bool) Channel locked

For example:

{
  "channelId": 25,
  "frequency": 331000000,
  "power": 4.4,
  "modulation": "qam_256",
  "snr": 41,
  "rxMer": 41,
  "correctedErrors": 18,
  "uncorrectedErrors": 22,
  "lockStatus": true
}

The returned value for power is 10x greater on DOCSIS 3.1 channels than on DOCSIS 3.0 channels, therefore they need to be normalised.

Note: It has been noted that the corrected count is displayed as "Pre RS errors" in the Superhub UI, and uncorrected is displayed as "post RS errors". The number for post was higher than pre which didn't make sense and I assume that the Superhub 5 displays this data incorrectly.

Upstream

.upstream.channels is similar to that of downstream and contains an array of upstream channels. Each channel is made up of:

channelId - Channel ID
frequency - Frequench in hertz
lockStatus - (Bool) Channel locked
power - Power in dBmV
modulation - Channel modulation (map below)
t1Timeout - T1 Timeout count
t2Timeout - T2 Timeout count
t3Timeout - T3 Timeout count
t4Timeout - T4 Timeout count
channelType - Type of upstream channel

For example:

{
  "channelId": 1,
  "frequency": 60300000,
  "lockStatus": true,
  "power": 44.3,
  "symbolRate": 5120,
  "modulation": "qam_64",
  "t1Timeout": 0,
  "t2Timeout": 0,
  "t3Timeout": 0,
  "t4Timeout": 0,
  "channelType": "atdma"
}

The returned value for power is 10x greater on DOCSIS 3.1 channels than on DOCSIS 3.0 channels, therefore they need to be normalised.

Service Flows

To get the upstream and downstream rate/burst, we need to read from an array at .serviceFlows. Each object will contain an object at .serviceFlow.

We are interested in the value where direction == "downstream" or direction == "upstream".

Example:

{
  "serviceFlow": {
    "serviceFlowId": 17980,
    "direction": "downstream",
    "maxTrafficRate": 402500089,
    "maxTrafficBurst": 42600,
    "minReservedRate": 0,
    "maxConcatenatedBurst": 0,
    "scheduleType": "undefined"
  }
}

Modulation Map

Modulation is mapped by /common/js/networkstatus.js in the following ways:

var MODULATION_MAP = {
    qpsk        : "QPSK",
    qam_8       : "QAM 8",
    qam_16      : "QAM 16",
    qam_32      : "QAM 32",
    qam_64      : "QAM 64",
    qam_128     : "QAM 128",
    qam_256     : "QAM 256",
    other       : "rs46",
    unsupported : "c_st30",
    error       : "c_st30",
    unknown     : "c_cd04" // 'Unknown'
};

# README