S&T's CDL Monitor
S&T provides software for the analysis of OCAP Common Download carousels. Quite often there
a number of external factors, essentially neither the set-top-box or TSBroadcaster, which can cause
a code download to fail. Such factors include:
- Overloaded or slow network connection betweem TSBroadcaster and the CMTS (for DSG delivery) or QAM modulalor (in-band).
- Firewalls or switches that block multicast packets (DSG delivery).
- UDP buffer size on the TSBroadcaster host Linux system.
- Inadequate hardware platform for TSBroadcaster, possibly not enough RAM or a too slow CPU.
In addition, a poorly configured TSBroadcaster system can also result in download errors. For example:
- Where there are multiple TSBroadcasters present, more than one system sending DSM-CC data carousels to the same multicast DSG application tunnel id.
- Where there are multiple CVTs and DSG outputs defined, sending a CVT which references the incorrect application tunnel id.
- Sending a CVT which references an incorrect co-signer CVC.
- Inappropriate settings defined in the TSBroadcaster system.properties file, .e.g. setting output.oobdcSchedulingIntervalMs to a value which causes output to be too bursty for the receiver.
- Selecting a carousel output bitrate which is too high for the set-top-box.
This software is designed to help detect the above and other causes of code download failure.
The CDL Monitor is provied by S&T as software only and should be installed on any suitable Linux system.
The analyser produces results which include:
- A count of Application Tunnel, other UDP, non-UDP and non-IP packets.
- The UDP traffic flow from the source IP to the multicast IP address and port.
- Counts of PAT, PMT and DII PIDs.
- Data on downloadId, txnid block size, version and modules count.
- For each DII, the module information, including downloadId, a version, size (in bytes and blocks) and code image name.
- For each module, the id, a first, last and interval.
- Detection of UDP packets dropped from a module.
- The CDL Monitor can accept a pre-captured PCAP file for input. Such files are generated either by Linux tcpdump(1) or WireShark.
- Alternatively CDL Monitor will operate in a realtime mode and capture data from either unicast or multicast UDP at any point in the delivery chain prior to conversion of the carousel into RF.