Aaron KE5KAF (aka atms169) wrote:

>> Upload speed was upgraded to a T1 line and 
>> download is 10mb using Cable.  

As written this doesn't make sense.

Are you saying you have a cable provider internet
connection that has upload speed of 1.54 mpbs and
download of 10 mbps?  Or you are using separate 
connections: a T1 for upload and cable for download?


> I pay for this specific bandwidth.
> 
> Yes, tests were run inside the TWC network and outside.
> 
> [ED: In trying to help diagnose your problem, people 
> need as much detail as possible, such as what tests?  
> Only bandwidth, or more detailed analysis.]

I listened to your MP3 file and agree ... 
the audio is horrible.

Based on the bandwidth you have indicated you've 
purchased ... the problem is likely not bandwidth,
especially if this happens with one connection 
from your D-STAR gateway to another gateway or
reflector system (as the amount of bandwidth used 
by a single stream is pretty light and would only 
be a small percentage of your subscription).

As others have pointed out - and I concur ...
you need to do some end-to-end tests from your
gateway computer to another system somewhere 
on the Internet.  Maybe another gateway that
you've connected to that has exhibited the
audio problem?

You need to confirm that you can stream sufficient
UDP packets to and from your D-STAR gateway system
without excessive jitter or being dropped or delivered
out of order.

If you're on Time Warner Cable ... do some 
traceroutes from your D-STAR gateway to a
number of other gateways that you've experienced
this problem with.  Note how your packets 
transverse TWC's network ... and what peers
TWC is connected to.  Do all traceroutes take
the same route leaving the TWC network?
(You can tell by the rDNS host names.)

There is always the chance that the TWC network
is fine ... but somewhere further out on to the
Internet there is an issue - anywhere from the
routers/switches that interconnect TWC to the 'net
to any other provider's network.

Here's a similar example:  I have had at the home QTH
the same SDSL connection for years.  This is provided 
on a separate copper pair (without dialtone) by a CLEC
(not the regular telephone company).  SDSL is the
same speed up and down; a business class connection.

I used to have a Vonage device and it worked fine.
But a few years ago the quality started degrading
and it was traced back to the fact that the UDP
packets to/from the Vonage connection on the net
were not being reliably delivered.

You may be having problems where UDP packets:
- are occasionally being dropped, or
- occasionally being delivered out of order, or
- the time it takes to get from one end to another
  is varying widely.

Ideally when you're doing an application like VoIP
or D-STAR gateway interconnects you'll want to see
minimum transit time of the UDP packets with no 
variance in the amount of time it takes to deliver
and all packets received in the order sent.  That's 
easy to do when you own/manage the entire network 
and a bit more difficult when you have to transverse
multiple networks like on the Internet.

Is your internet connection a residential grade
or business grade service?   With residential 
cable service often the activities of other people
in the immediate area will affect your connection.

Is everything on your D-STAR gateway system locked
down, i.e., inaccessible from the Internet?
This includes the HTTPS registration interface.

If not - consider that ANY open port on your router
could be probed by script kiddies on the Internet ...
and you may be having occasional attacks attempting
to find vulnerabilities on your gateway.
(Beyond that - be sure that there's no unexpected
activity on your gateway, e.g., ensure that it has
not been compromised.)

What are you running between the D-STAR gateway
and the cable modem?  (What kind of router or
firewall?)  

Does your router or firewall device have the ability
to tell you what hosts (logging) are being accessed
for all traffic inbound and outbound?  Look for 
unexpected traffic ...

Do you have anything else at all that is running
on this same internet connection?  (Another system,
IRLP node, etc. on the trusted side of the network?)
If so - traffic from that/those systems may be 
affecting the D-STAR gateway stream(s).

Do you have access to an EVDO (SprintPCS, VZW) or
EDGE (T-Mobile, AT&T) connection?  If so - try to
connect your D-STAR gateway to that to rule out the
TWC internet connectivity.

I also have a dongle and have experimented a bit
with it as well.  Its quality is very much subject
to the Internet connection; I was recently at the 
EME conference in Florence, Italy where I had a
WiFi connection in the hotel.  Upload and download
speeds exceeded 1.0 mpbs - but even at 01:00 local
I had times where I got nothing over the dongle 
connection back to local systems in eastern US.
And at other times very garbled.  So even running
the DSL Reports (or whatever) speed tests ...
you don't get the full story.

Lastly - I also concur with other folks who've responded:
if two people can communicate via RF through the repeater
without the audio degradation ... and if you have more 
than one band module - from one module to another ...
that really helps confirm that your stack of D-STAR gear
is working fine.  I wouldn't waste a lot of time with 
the RF side of the plant ... but otherwise concentrate
on everything from the Ethernet cable connected to your
D-STAR repeater controller to your D-STAR gateway 
computer and out to the Internet.

As the list moderator pointed out: it would be very
helpful if you could provide some additional details
about your configuration and what tests have been run.

I know its probably discouraging to both you and your
system's users - but keep at it ... and hopefully with
some additional details and recommendations that you've
received from this list you can get a handle on this.

GL es 73
Bob W1QA


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