"Ignore DVB-C namespace sub network" What does it mean/do?

[Kojo_]

Need some assistance figuring out what this setting does.

And that setting has a "tooltip" saying: "On valid ONIDs, ignore frequency sub network part".

[EnoSat]

Ignore namespace ON - XXXXxxxx - transponders with the same TID-NID will be overwritten last in the search (e.g. FFFF0000)
Ignore namespace OFF - XXXXxxxx - transponders with the same TID-NID will not be overwritten but added (e.g. FFFFABCD or FFFF0123)
(where - XXXX - position and xxxx - frequency)

[abu baniaz]

Question would sound better being inverted. Include instead of ignore. Avoids a double negative when advising people what to do.

[EnoSat]

A small example:
On 570 MHz, MUX1 transmits with quality parameters (MER-40dB) and on 642 MHz, MUX1 transmits with worse parameters (MER-20dB).
With Ignore ON, after scanning, MUX1 from 570 MHz will be overwritten by MUX1 from 642 MHz (only worse will remain).
With Ignore OFF, after scanning, MUX1 will be twice (both better and worse).

[el bandido]

I have terrestrial ATSC channels, where some channels transmit the same ONID I had to modify the lamedb file before this option was available or I would get dead services with the error message "SID not found in PAT".

The Ignore namespace option has been available for some 6 years. interesting to see it discussed now. Here is the commit description from 2017:

scan: do not ingore namespace subnetwork

By default the namespace contains only part of the hash that is possible to store
because when we are having valid ONID we are ingoring the last 2 bytes (subnetwork).

That is happening when isValidONIDTSID is true and that exists since the initial
import of enigma2 in git.

In the subnetwork we are storing the frequency and polarization for sat
and frequency for other systems and that solves all the problematic cases where
same ONID is appeared twice, without hardcoding exceptions in isValidONIDTSID.

Although by not ingoring the subnetwork all the service references will change
making at least picons unusable.

The findPicon can be optimized to ingore the subnetwork and that will be fixed
by another.

Ideally the namespace should not ingore the subnetwork and isValidONIDTSID
check can go away, once there are no issues preventing to do so.

[Huevos]

Need some assistance figuring out what this setting does.

And that setting has a "tooltip" saying: "On valid ONIDs, ignore frequency sub network part".

The simple answer is leave it set to "no" unless you understand why you are enabling it. Enabling this when not needed will cause problems.

It is only required when two receivable multiplexes have the same identifier, which should never happen for DTH multiplexes.

[EnoSat]

However, it is very common with feeds. Many transponders on one position use the same SID/TID/NID

[Huevos]

However, it is very common with feeds. Many transponders on one position use the same SID/TID/NID

if onid == 0 or onid == 1 and tsid < 2 or onid >= 0xff00:

Those are the conditions for turning on namespace automatically. In theory feeds should fall within those ranges.