Category Archives: TAC

iDX 3.2.3.5 Patch Release and New Tech Bulletins Available

The iDX 3.2.3.5 remote-only patch release is now available.

This patch resolves issues reported from the field. The issues concern:

  • Resolving the ability to SSH between iDirect remotes and other network devices
  • Resolving issues related to remotes being commanded offline in 3.2.x.x releases
  • Resolving the issue related to 27 MHz being enabled by default on X7 remotes

Details are now available in the 3.2.3.x release notes located on our Partner Technical Assistance Center (TAC).

Three new technical bulletins available

iDirect TAC has three tech bulletins now available:

  • CPU usage increase when performing SSH
  • Process crash when processing specific  type of IGMP packets
  • X7 remotes have 27 MHz signal enabled by default in some 3.2.x. releases

Further details are included in the bulletins located on our Partner Technical Assistance Center (TAC).

If you have any questions, please contact the TAC at +1-703-648-8151 or contact tac@idirect.net.

iDirect Network Upgrade Procedures and Release Notes

To ensure that iDirect’s Technical Assistance Center (TAC) captures changes,  defect workarounds or other field issues, the Network Upgrade Procedures and Release Notes are updated quite frequently. However, it has been discovered that sometimes  folks download a version of a certain document and keep using it over and over. Partners need to be aware that this could be very dangerous, especially in the case of Network Upgrade Procedures (NUP). There have been critical updates to both 3.2.x.x and 3.3.x.x NUPs in the past few days/weeks and not using the most current version can cause serious upgrade issues.

It is strongly recommended that anytime you use a critical Release Document, please download the most current version from the TAC Web Page. This is especially important for Network Upgrade Procedures, Upgrade Surveys and Release Notes.

For questions, please contact our TAC.

Database Backups Maintenance Tips

Database backup is a critical maintenance operation. All operators should periodically check for appropriate frequency of backup, duration of backup and any errors in database backup.

Frequency: Examine the Crontab to make sure the Primary NMS is backed up to the Backup NMS once daily.

Duration: Examine backup log and cons.output to make sure Backups are complete within 30 minutes. (This can take longer for networks large number of remotes.) Also make sure the timings of Consolidation and Backup scripts do not overlap. The latest Consolidator log should finish before the most recent backup starts. Otherwise, consider altering the database backup time in crontab so that the database backup starts after the consolidation finishes.

Errors: Check to make sure no errors are recorded in the cons.output and dbbackup.output files.

iDX 3.2.3 Software Release Now Available

iDX 3.2.3 is a GA release, which includes additional features and addresses bug fixes found as a result of our continued internal test efforts as well as from field feedback. Additional features include:

  • Virtual Router Redundancy Protocol (VRRP) for X5/X7
  • Remote LAN Port Monitoring for X5/X7

For more details please consult the release notes on the Technical Assistance Center (TAC) as well as for all other related documentation for this release.

The Concept of Reference Carrier in iDX 3.2

The concept of a Reference Carrier was introduced in iDX Release 3.2 to account for per-carrier differences in transmit power required for remote acquisition bursts. The Reference Carrier is defined in iBuilder on the Remote Information tab and includes the following parameters:

  • Symbol Rate
  • MODCOD
  • TDMA Initial Power
  • Spreading Factor
  • Payload Size

The TDMA Initial Power is configured in relation to the remaining Reference Carrier parameters. The correct setting for the TDMA Initial Power is typically determined during remote commissioning. The TDMA Initial Power determines the transmit power of the remote’s acquisition bursts.

A remote that has not yet acquired the network is continuously assigned acquisition slots on upstream carriers until the hub line card receives an acquisition burst from the remote in an assigned slot. The upstream carrier on which the remote is invited to transmit an acquisition burst can change at any time. It is important that all bursts on a given carrier (including acquisition bursts) are received by the hub line card at a similar Carrier to Noise ratio (C/N). For in-network remotes, the Uplink Control Process (UCP) at the hub regulates the transmit powers of each remote’s traffic bursts such that all bursts are received within the optimal C/N range. However, UCP is not active for remotes transmitting acquisition bursts. Therefore, the system relies on the configured TDMA Initial Power to set the correct transmit power for acquisition bursts. Read More

‘Improved Roll Off Factor’ for DVB-S2 Carriers

Beginning with iDX Release 3.2, improvements to the iDirect carrier waveform allow reduced guard bands for DVB-S2 downstream carriers. In earlier releases, iDirect required a minimum guard band of 20% of the carrier symbol rate for both upstream and downstream carriers. For DVB-S2 downstream carriers, the required guard band now can be as small to 5% of the carrier symbol rate for some carriers. This improved guard band requirement was achieved by reducing the roll off factor of DVB-S2 downstream carriers.

Digital communication systems employ waveform pulse shaping using identical matched transmit and receive filters to limit the occupied bandwidth required by a carrier and to maximize received Signal to Noise Ratio (SNR). The roll off factor of a digital filter defines how much more bandwidth the filter occupies than that of an ideal “brick wall” filter which defines the theoretical minimum occupied bandwidth. This dictates the guard band requirement for the carrier.

A lower guard band between adjacent carriers makes it possible to fit a higher bit rate carrier into the same satellite bandwidth. Therefore, with a lower guard band requirement, a Network Operator can increase the bit rate of existing carriers without purchasing additional bandwidth.

The amount of required guard band between carriers can be expressed as the carrier spacing requirement. For example, if the required guard band is 20%, the channel spacing requirement is 1.2*Carrier Symbol Rate in Hz. Carrier Spacing can be configured in iBuilder for both upstream and downstream carriers. This field is used to document the total occupied bandwidth of the carriers. It represents the carrier bandwidth plus the guard band normalized by the symbol rate. Read More

iDX 3.2.2.7 Software Release Now Available

iDirect is excited to announce the release of our latest iDX 3.2 software release. iDX 3.2.2.7, is now available. The 3.2 release introduces new hardware and features to optimize your iDirect network while enabling service revenues and reducing total cost of ownership. Together with the new X7 remote, this release delivers next-generation performance and is HTS-ready:

  • High performance TDMA remote to support bandwidth heavy applications
  • Adaptive TDMA on the return channel to lower bandwidth costs and increase  network availability
  • Improved acquisition, roll-off factor and waveform

iDX 3.2.2.7 is a full release and it addresses several operational and functional issues primarily on the remotes side found as a result of our continued internal test efforts as well as from field feedback. For more details please consult the release notes on the Technical Assistance Center (TAC).

Please visit the TAC for Release Notes and all other related documentation for this release.

Downstream Template Feature in iDX 3.2

Evolution X1, X7, and e150 Satellite Routers support the Downstream Template feature in Web iSite. This feature was introduced in iDX Release 3.2 as an option to speed commissioning of large numbers of remote sites by avoiding the requirement for the installer to obtain and manage a large number of individual options files. This feature also allows the Satellite Router to receive its remote software package over-the-air from the NMS as part of the commissioning procedure.

The Downstream Template contains the minimum information necessary to enable reception of the downstream carrier from the hub. Remote sites in the same network with identical LNB parameters can use a single Downstream Template file to enable reception on all the remotes in that network. Once the Downstream Template is loaded into Web iSite and the modem locks to the downstream carrier, the Network Operator uses iBuilder to download the remote software package and the remainder of the site-specific options data over-the-air from the NMS.

The Downstream Template file is produced by the Network Operator. It is a text file in JSON format that can be viewed and edited with a text editor such as Notepad. Downstream Template files must have the .json file extension in the file name. An example of an iDX 3.2 Downstream Template JSON file is shown here. Read More

iDirect TAC Tips – TDM Lost

TDM Lost

What are they?
They are an aggregate count of the number of times the remotes demodulator has lost lock on the Hubs Downstream carrier since remote was reset.

Where are they measured?
For QPSK, the 8 bit I and Q soft decision data is sampled at the symbol rate after demodulation on the iNFINITI remote.

How are these calculated?
The sign bit of each signal (hard decision) is correlated separately with the known 32 symbol UW (Unique Word) sequence. When a UW sequence passes through the correlators and all bits of I and Q match, there is a perfect correlation of 64 matches. For BPSK, only the I channel is correlated so the perfect correlation is 32 matches.

Since the channel is noisy, thresholds lower than the perfect correlation are used. A high correlation is used during initial acquisition to prevent a false lock and then once frame lock is achieved, a lower threshold is used to ride out periods of low SNR.

A coincident detection and aperturing method is employed to make the circuit more robust. Since the number of symbols per frame N is known, when the first UW sequence is detected, the circuit waits exactly N symbols before checking for another correlation. This one symbol aperture prevents false detection. After four UWs are detected in a row, TDM Lock is declared. If four in a row are missed, TDM Unlocked is declared.

What are FLL DAC limits on a remote?
FLL DAC lower limit is 0 and upper limit is 4096. If FLL DAC ever gets close to its upper limit of 4096 or its lower limit of 0, this indicates that its local oscillator is not able to lock to the bit timing of the downstream carrier.  This may cause remote to loose downstream carrier lock.

iMonitor is configured by default to show FLL DAC warnings for readings lower/higher than %12.5 of min/max limits (min. warning limit= 512, and max warning limit= 3584)

iDirect TAC Tips – Information on Fast Fade Corr, CRC8/CRC32 errors and NCR lock lost counters

Information on Fast Fade Corr, CRC8/CRC32 errors and NCR lock lost counters

“Fast Fade Corr” stands for “fast fade correction” and is the number of times the remote was detected (by the hub) as going into a fast fade condition. A fast fade condition is where the remote’s reported Downstream SNR drops more than a certain amount in a certain period of time. When this is detected, the system drops the MODCOD of the remote (assuming DVB-S2 ACM mode here) way more than a normal adjustment, to try and compensate for the sudden drop in signal strength, hence keeping remote from dropping out of the network. You can read more in iBuilder User guide under section “5.12 DVB-S2 Network Parameters”, that is where you can learn how to adjust these.

What are CRC8/CRC32 errors?

In DVB-S2 carriers, the classic “SCPC errors” don’t exist. In DVB-S2, these have been replaced by CRC8 and CRC32 errors.

Below is a description of how they work.

The basic building block of the DVB carrier is called the BaseBand Frame (BBFrame). CRC8 and CRC32 errors will provide two separate levels of error checking, each is responsible for different segments of the BBFrame. Read More

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