Hi,

I've been running a multimode gateway using AllStar and DVSwitch for the
better part of 2 months.  Currently, on the digital side, I support DMR
(Brandmeister), D-STAR (My own XLX), YSF and P25. 

The system puts AllStar at the centre.  This was a deliberate decision,
to ensure that no matter the source and destination, there is never any
more than one (xMBE) transcoding cycle, regardless of source and
destination.  And in the case of YSF <--> DMR, no transcoding at all, as
I have a separate MMDVM_Bridge between those two modes.

Basically, I have an AllStar node which has 3 private nodes, each of
which is linked to a branch of digital systems - each branch uses a
different *MBE codec.  These private nodes are permanently linked to the
main node (and effectively each other) to form a complete system, so
I'll just discuss the private nodes to digital section.

There are 3 private nodes that link to the various digital systems. 
They are configured as follows:
1997 <--> Analog_Bridge <--> MMDVM_Bridge <-->  Brandmeister.
1998 <--> Analog_Bridge <--> MMDVM_Bridge <--> P25Gateway <--> P25Reflector
1999 <--> DummyRepeater <--> ircDDBGateway <--> XLX
Brandmeister <--> MMDVM_Bridge <--> YSFReflector

Note:  D-STAR is configured using the version of DummyRepeater patched
with USRP support.  DummyRepeater is used, so I can make use of a DV
Dongle (the original blue one) that I already had on hand to process the
DSAMBE audio.  Besides cost (and waste), delivery time uncertainties
were another reason not to order new hardware for the DSAMBE
processing.  Goods from overseas are taking an unpredictable amount of
time to get here from overseas (used to be 1-2 weeks from the US, can be
way more than a month now, due to COVID).

Everything is working well, with great audio between the different
modes, and it can be really difficult to tell where people are entering
the system, as other than D-STAR (quality is slightly less D-STAR to the
other modes), there's no easily noticed artifacts in the audio.

However, because AllStar is in the middle, I do lose the callsign/ID
metadata on most streams, with the only exception being between DMR and
YSF.  Since everyone IDs, and there's analog systems on the other side
of AllStar (I haven't elaborated, since the details aren't relevant to
this post), this is more of a cosmetic issue than a serious one, and I'm
happy to keep running things as they are, if there's no better solutions.

What I'm asking is if there's a better topology for such a gateway that
preserves audio quality?  Or is there a way somehow to pass metadata
between the digital links, while leaving the audio going via AllStar?


--
73 de Tony VK3JED/VK3IRL
http://vkradio.com