VIOP DOS

[Richmond]

No, not VOIP for MSDOS. :) I am wondering if the new VOIP telephone
network which replaces PSTN will be vulnerable to denial of service
attacks?

[Richmond]

https://www.voipfonestatus.co.uk/


"Identified - We have identified a further DDoS attack, we will post
updates as the situation develops. Aug 31, 18:25 BST"

This happened last week too.

[Theo]

I'd guess it depends if your ISP puts their servers on the public internet
or not. Given your router is talking directly to their SIP server, it could
conceivably be on a VLAN/IP that isn't publically routable and so can't
receive traffic except from their own customers.

Although how it gets the calls onwards from there is another question -
probably some part of the call is going to go over the internet at some
point, unless they build a completely separate IP network for routing calls.

Theo

[David Woolley]

As the current ones are, I don't see why their replacements shouldn't
be. They are all deliberately designed without enough capacity to cope
with everyone calling at once, and can be brought down by phone in
programmes and disasters. I believe the London mobile networks had to
be shut down for ordinary users on 7/7 because all the calls were
denying service to the emergency services.

There is a branch of applied maths, called tele-traffic engineering,
which is all about designing systems with enough capacity to normally
not overload, but not enough capacity to cope with anything even close
to the worst case. At one time, about one in twenty calls were allowed
to fail at normal peak times, through lack of capacity.

[Woody]

The priority system was invoked on 7/7 by the City of London police as
the Met could and would not justify the charges involved. It didn't stop
ordinary people make calls but if someone with higher priority needed to
use it the existing call that had been running for the longest that had
no priority rating would be dropped - a system known as pre-emptive
cleardown.

The limitations that this put on operation made the local authority
rethink its operations and return to 'normal' mobile radio which I
believe has no converted to digital operation.

[Richmond]

I think that the DDOS attack is different in that the attackers aren't
necessarily making phone calls. They can have a botnet of compromised
IOT devices, so it need not cost them anything and they can be
anonymous.

I hope that the network which replaces analog phone lines will be
dedicated in some way and not use the same internet as everything else.

But if you can compromise a router, presumably you can compromise an ATA
or a VOIP phone. Do hardware VOIP phones get software updates?

What could possibly go wrong?

[notya...@gmail.com]

On Thursday - took down their web site too. Late afternoon. I don't think established calls were affected because they don't go through Voipfone's servers.

First major outage I can recall on Voipfone in around 15 years. We had two BT internet outages in a week a few years back - one all day. This took them below their claimed 99.9% up time (now re covered) and they would not even refund the rental for the lost day's service!

[notya...@gmail.com]

On Wednesday, 1 September 2021 at 17:04:37 UTC+1, Richmond wrote:
> David Woolley <da...@ex.djwhome.demon.invalid> writes:
>
> > On 31/08/2021 17:36, Richmond wrote:
> >> No, not VOIP for MSDOS. :) I am wondering if the new VOIP telephone
> >> network which replaces PSTN will be vulnerable to denial of service
> >> attacks?
> >>
> >
> > As the current ones are, I don't see why their replacements shouldn't
> > be. They are all deliberately designed without enough capacity to
> > cope with everyone calling at once, and can be brought down by phone
> > in programmes and disasters. I believe the London mobile networks had
> > to be shut down for ordinary users on 7/7 because all the calls were
> > denying service to the emergency services.
> >
> > There is a branch of applied maths, called tele-traffic engineering,
> > which is all about designing systems with enough capacity to normally
> > not overload, but not enough capacity to cope with anything even close
> > to the worst case. At one time, about one in twenty calls were
> > allowed to fail at normal peak times, through lack of capacity.
> I think that the DDOS attack is different in that the attackers aren't
> necessarily making phone calls. They can have a botnet of compromised
> IOT devices, so it need not cost them anything and they can be
> anonymous.

Given major VoIP providers essentially publish their IP address (Voipfone's is 46.31.225.185) the attackers just hammer the address with minor requests from hundreds of infected computers.

Very difficult to fight off. Heavy duty firewall perhaps?

>
> I hope that the network which replaces analog phone lines will be
> dedicated in some way and not use the same internet as everything else.
>
> But if you can compromise a router, presumably you can compromise an ATA
> or a VOIP phone. Do hardware VOIP phones get software updates?

Siemens Gigaset do, although my old ones haven't had an update for years - still work though.

[Richmond]

"notya...@gmail.com" <notya...@gmail.com> writes:

> Given major VoIP providers essentially publish their IP address
> (Voipfone's is 46.31.225.185) the attackers just hammer the address
> with minor requests from hundreds of infected computers.
>
> Very difficult to fight off. Heavy duty firewall perhaps?
>

I think the only way to fight it off is to have enough band width to
ride the storm, which you do by using something like cloudflare.

But the new phone network could be a completely seperate internet
network from the current Internet and VOIP providers. I guess there is a
plan somewhere as to how they are going to do this.

[Woody]

Ha! Optimist. That would cost money and affect the bottom line so beggar
the customers.

[Richmond]

Well we need to nationalise the whole thing, then use the magic money
tree, which has now been shown to exist.

[David Woolley]

On 01/09/2021 17:53, Richmond wrote:
> But the new phone network could be a completely seperate internet
> network from the current Internet and VOIP providers. I guess there is a
> plan somewhere as to how they are going to do this.

That would negate the benefits of using VoIP. A dedicated network would
be better off using ATM, or even simple TDM. The point of VoIP is it is
a small user that can be fitted into the gaps in the traffic, possibly
with some prioritisation. Once you have to dedicate resources, you will
end up tele-traffic engineering those to 95 percentile loads.

[Theo]

Not entirely. The purpose of this transition is to get rid of analogue
signalling on the local loop. That means no voice line cards, no ring
current, no line-powered phones, no backup generators, no telephone
exchanges. You just have a DSLAM in your cabinet backhauled into a fibre
and that's it.

Once it's running on the fibre it's up to Openreach what to do with it. It
makes more sense to run it as IP over the broadband pipe, rather than ATM or
TDM, but that's not to say it can't be VLANned into a separate channel with
prioritisation to make sure it gets through. And then when that VLAN lands
at the ISP it's up to them.

While I've done a bit of reverse engineering of the Sky SOGEA stack I don't
know how it routes out of their box and whether their SIP server is
accessible from the internet side or is VLANned off somewhere else.
(I should probably take another look out of curiosity)

Theo

[notya...@gmail.com]

Not actually very difficult, simply change the protocol on inter exchange links from CCITT (now ITU) No. 7 to TCP/IP, with a consequential increase in call capacity.

[Richmond]

That's a packed sentence. So inter exchange links are already digital?
presumably because they are fibre optic. And so I would have a seperate
router to provide an ADSL link over my copper EO line to the exchange?

Can I have two ADSL routers on the same telephone line? Or maybe I could
have two networks on the same router?

[David Woolley]

On 03/09/2021 19:29, notya...@gmail.com wrote:
> Not actually very difficult, simply change the protocol on inter exchange links from CCITT (now ITU) No. 7 to TCP/IP, with a consequential increase in call capacity.

SS7 is only a signalling protocol, so doesn't address the media stream
at all, which it assumes is circuit switched. Also it is a layer 7
protocol. If you are referring to the lower layer protocols, I think
they are actually lighter weight than TCP/IP, so the capacity may be
lowered.

The actual predecessor to C21 networks is ATM, and it, in turn, replaces
the TDM system. ATM is already, I believe, used to carry the back haul
for ISP traffic, and the ADSL protocol actually seems to have elements
of ATM in it. ATM is packet switched, but with small packets and
reserved bandwidth for those carrying speech. I would presume it
already introduces statistical multiplexing benefits.

I suspect the reason for VoIP in the backbone network is that speech is
now only a small part of the traffic, and there are economies in
re-using software and hardware originally intended for data.

[David Woolley]

On 03/09/2021 21:16, Richmond wrote:
> That's a packed sentence. So inter exchange links are already digital?

They have been since the 1980s.

> presumably because they are fibre optic. And so I would have a seperate

The original ones where over coaxial cables.

> router to provide an ADSL link over my copper EO line to the exchange?

ADSL is a means of transmitting over analogue media, whereas as E0 is
digital all the way.

>
> Can I have two ADSL routers on the same telephone line? Or maybe I could
> have two networks on the same router?

You can have multiple ATM streams over a single ADSL connection (i.e.
the same router), although consumer grade equipment may not support
this. (I don't know if BT Internet use this to provide public hotspots,
or whether they just multiplex at the IP level.) I don't know how
bandwidth is managed in such circumstances.

(It may also be used for providing TV and internet over the same cable.)

Incidentally the basic research on all this was also done in the 1980s,
although at the time they saw it as primarily just video on demand, but
maybe that's what the internet is becoming, anyway.

[grinch]

On 03/09/2021 21:16, Richmond wrote:
> "notya...@gmail.com" <notya...@gmail.com> writes:
>
>> On Wednesday, 1 September 2021 at 17:53:11 UTC+1, Richmond wrote:
>>> "notya...@gmail.com" <notya...@gmail.com> writes:
>>>
>>>> Given major VoIP providers essentially publish their IP address
>>>> (Voipfone's is 46.31.225.185) the attackers just hammer the address
>>>> with minor requests from hundreds of infected computers.
>>>>
>>>> Very difficult to fight off. Heavy duty firewall perhaps?
>>>>
>>> I think the only way to fight it off is to have enough band width to
>>> ride the storm, which you do by using something like cloudflare.
>>>
>>> But the new phone network could be a completely seperate internet
>>> network from the current Internet and VOIP providers. I guess there is a
>>> plan somewhere as to how they are going to do this.
>>
>> Not actually very difficult, simply change the protocol on inter
>> exchange links from CCITT (now ITU) No. 7 to TCP/IP, with a
>> consequential increase in call capacity.

As the exchanges (pots)are being switched off and scraped by 2025 why
would you possibly want to do that ?

> That's a packed sentence. So inter exchange links are already digital?
> presumably because they are fibre optic.

Yes as they have been since at least 1993 when I started in working
comms probably much earlier.

And so I would have a seperate
> router to provide an ADSL link over my copper EO line to the exchange?
>

No

> Can I have two ADSL routers on the same telephone line?

Not if you want it to work

Or maybe I could
> have two networks on the same router?

If you use RFC 1918 IP space as many as you want ,then just NAT to your
external IP address provided by your ISP.

I think your missing the point here using time domain technology to
transmit voice is being scrapped by 2025, not before time. All traffic
will work over an IP based network. The clue is in the name of this
newsgroup.

[Andy Burns]

David Woolley wrote:

> Richmond wrote:
>
>> so I would have a seperate

>> router to provide an ADSL link over my copper EO line to the exchange?
>
> ADSL is a means of transmitting over analogue media, whereas as E0 is
> digital all the way.

I think he means "Exchange Only" ...

[David Woolley]

On 04/09/2021 12:53, Andy Burns wrote:
>>
>> ADSL is a means of transmitting over analogue media, whereas as E0 is
>> digital all the way.
>
> I think he means "Exchange Only" ...

Oops. I saw the E and thought E1.

The rest is OK though; ADSL is designed to carry multiple streams at the
ATM level, although I've never researched it sufficiently to understand
how the bandwidth is managed.

[Andy Burns]

Richmond wrote:

> Can I have two ADSL routers on the same telephone line?

No

> Or maybe I could have two networks on the same router?

ADSL routers do allow for multiple virtual circuits, but I'm not aware
of anyone offering/using them, e.g. for an ISP connection and a direct
link to the office.

[Andy Burns]

David Woolley wrote:

> ADSL is designed to carry multiple streams at the
> ATM level, although I've never researched it sufficiently to understand
> how the bandwidth is managed.

Each PVC has its own CIR, which is probably ok when you have e.g. a 34Mb
or 622Mb circuit, but when it's whatever bandwidth the damp string can
manage today, which is never as fast as you'd like, I can see it
becoming a nightmare to slice it multiple ways

[Richmond]

grinch <gri...@somewhere.com> writes:

> I think your missing the point here using time domain technology to
> transmit voice is being scrapped by 2025, not before time. All traffic
> will work over an IP based network. The clue is in the name of this
> newsgroup.

I know that. Why don't you follow the thread from the beginning?

[Richmond]

And ransom demands it seems.

https://www.theregister.com/2021/09/02/uk_voip_telcos_revil_ransom/

"UK VoIP telco receives 'colossal ransom demand', reveals REvil
cybercrooks suspected of 'organised' DDoS attacks on UK VoIP companies"

[grinch]

On 04/09/2021 12:34, David Woolley wrote:
> On 03/09/2021 19:29, notya...@gmail.com wrote:
>> Not actually very difficult, simply change the protocol on inter
>> exchange links from CCITT (now ITU) No. 7 to TCP/IP, with a
>> consequential increase in call capacity.
>
> SS7 is only a signalling protocol, so doesn't address the media stream
> at all, which it assumes is circuit switched.  Also it is a layer 7
> protocol.  If you are referring to the lower layer protocols, I think
> they are actually lighter weight than TCP/IP, so the capacity may be
> lowered.
>
> The actual predecessor to C21 networks is ATM, and it, in turn, replaces
> the TDM system.  ATM is already, I believe, used to carry the back haul
> for ISP traffic, and the ADSL protocol actually seems to have elements
> of ATM in it.  ATM is packet switched, but with small packets and
> reserved bandwidth for those carrying speech.  I would presume it
> already introduces statistical multiplexing benefits.

I have worked for various ISPs as a networks engineer between 2000 and
2018 ,the last time any of them sold ATM circuits was 2005. I am sure
there are some legacy ATM links but they will be switched off as they
are old technology and expensive to maintain. Banks seem to use them(
atm links) for some reason ???

>
> I suspect the reason for VoIP in the backbone network is that speech is
> now only a small part of the traffic, and there are economies in
> re-using software and hardware originally intended for data.

The reason is simple POTS is very very expensive to maintain old
technology which requires specialist engineers and knowledge.

Also fixed line telephony has been loosing money for years and BT/OR
want to switch it off for commercial reasons.

Why keep a separate Voice system when you can put all data video and
voice over an IP backbone, which is much cheaper to maintain and simpler
and IMHO superior.

As I understand it the ultimate goal is to have a single MPLS based
backbone infrastructure which does most things except for very large
data circuits.

[Brian Gregory]

On 01/09/2021 17:53, Richmond wrote:

> I think the only way to fight it off is to have enough band width to
> ride the storm, which you do by using something like cloudflare.

a) AFAIK Cloudflare only do http/https at present. I guess they could
add SIP and RTP (or whatever would be needed).

b) I would think that a big central VoIP exchange for, say, the whole of
England, might be big enough to be as, or nearly as, DDoS resistant as a
Cloudflare data centre.

--
Brian Gregory (in England).

[Woody]

Eggs and baskets come to mind. Airwave users found that out the hard way!

[Richmond]

I've been googling. It seems that bandwidth isn't necessarily the
problem with SIP. This paper looks at mitigations but isn't very
conclusive.

https://www.mdpi.com/2079-9292/9/11/1827/pdf

[notya...@gmail.com]

On Friday, 3 September 2021 at 21:16:22 UTC+1, Richmond wrote:
> "notya...@gmail.com" <notya...@gmail.com> writes:
>

SNIP

> >
> > Not actually very difficult, simply change the protocol on inter
> > exchange links from CCITT (now ITU) No. 7 to TCP/IP, with a
> > consequential increase in call capacity.
> That's a packed sentence. So inter exchange links are already digital?

Yes since the 1990's. Trunks [between exchanges] were digital long before that.

> presumably because they are fibre optic. And so I would have a seperate
> router to provide an ADSL link over my copper EO line to the exchange?

A/VDSL runs over copper. Phone lines can be provisioned over fibre (we had some from Norweb in the late 90's - at that time ISDN).

You will need something to covert a digital exchange link to an analogue phone whether fibre, cable or a copper pair.

>
> Can I have two ADSL routers on the same telephone line?

No.

> Or maybe I could have two networks on the same router?

Possibly, but I don't know anyone who does it. DT used to provide analogue, ISDN and ADSL over the same line. For years BT falsely claimed this was not technically possible.

[notya...@gmail.com]

On Saturday, 4 September 2021 at 12:46:29 UTC+1, grinch wrote:
> On 03/09/2021 21:16, Richmond wrote:
> > "notya...@gmail.com" <notya...@gmail.com> writes:
> >

SNIP

> >>
> >> Not actually very difficult, simply change the protocol on inter
> >> exchange links from CCITT (now ITU) No. 7 to TCP/IP, with a
> >> consequential increase in call capacity.
> As the exchanges (pots)are being switched off and scraped by 2025 why
> would you possibly want to do that ?

Reuse the very expensive [to install] wires and increase capacity.

Of course one could use them to pull through new fibre.

> > That's a packed sentence. So inter exchange links are already digital?
> > presumably because they are fibre optic.
> Yes as they have been since at least 1993 when I started in working
> comms probably much earlier.

Slight mistake in earlier post 1995 / 1998 was when the last non digital exchange of any sort was retired in the UK.

The last non digital trunk exchange was retired in July 1990.

> And so I would have a seperate
> > router to provide an ADSL link over my copper EO line to the exchange?
> >
> No
> > Can I have two ADSL routers on the same telephone line?
> Not if you want it to work
> Or maybe I could
> > have two networks on the same router?
> If you use RFC 1918 IP space as many as you want ,then just NAT to your
> external IP address provided by your ISP.
>
> I think your missing the point here using time domain technology to
> transmit voice is being scrapped by 2025, not before time. All traffic
> will work over an IP based network. The clue is in the name of this
> newsgroup.

Indeed, but I guess the poster came here wondering what will replace his current line.

BTW BT currently provision business 'lines' with VoIP on a router.

[Mark]

On 31/08/2021 17:36, Richmond wrote:

> No, not VOIP for MSDOS. :) I am wondering if the new VOIP telephone
> network which replaces PSTN will be vulnerable to denial of service
> attacks?
>

I believe one role of Session Border Controllers (SBC) is to try to
mitigate against DDoS attacks.

[Brian Gregory]

I wonder if some providers will choose to have their VoIP customers on
separate networks that aren't accessible from the rest of the Internet?

(The same way that BT uses a separate connection multiplexed over the
same link for TR-069 to monitor and update the routers they provide)

[Chloe]

On Tue, 7 Sep 2021 07:13:23 -0700 (PDT),
notya...@gmail.com <notya...@gmail.com> wrote:
>
>> Or maybe I could have two networks on the same router?
>
> Possibly, but I don't know anyone who does it. DT used to provide
> analogue, ISDN and ADSL over the same line. For years BT falsely
> claimed this was not technically possible.

That's because BT's implimentation of ADSL used some of the same frequency
range as ISDN, and DT's implimentation didn't.

So BT were correct, it was not technically possible on their adsl platform.

Chloe

[Richmond]

I mentioned this earlier in the thread and people suggest this is not
cost effective, or rather the cheaper option is to share with other
internet traffic.

I fear what is going to happen is we will lose the quality and
reliability of analog lines, and we'll get something cheap and
unreliable instead because that's what the competition is. I've done it
myself, rather than pay 3p I pay 1.2p over VOIP or whatever.

Analog doesn't sound very good because of the restricted frequency
range, but it is real time usually, and it doesn't have drop-outs. VOIP
is sometimes unavailable, and it has latency, and with sipgate there is
often echo.

[notya...@gmail.com]

Oh so BT couldn't have used DT equipment on the lines of customers who did want both?

BT lied about this and we both know it.

To rub it in BT made their claim when DT doing it was on the front page of Computer Weekly.

[notya...@gmail.com]

Just no my experience at all. Yes Voipfone was taken down by DDoS attack last week. BT lines get taken down by weather and their careless engineers.

As for call quality it is better on VoIP than POTS and the only bit of any current UK phone call that is analogue is a few km of wire between your phone and the local exchange, and perhaps the same at the other end. ADSL put my phone back to analogue, but for over a decade before that it was ISDN, and I even had an Ericson ISDN phone. Quality was better on that too.

I suppose you will claim that vinyl is better than CD and a valve amp better than transistor...

[Richmond]

No I wouldn't claim that, but some do. But my phone line is an exchange
only line that goes 1KM. So maybe I don't get a very good uplink. The
bandwith on uploads is considerably less than downloads. There is small
but noticable delay with the VOIP services I have used - sipgate and
voiptalk.

[David Woolley]

On 10/09/2021 15:23, Richmond wrote:
> it has latency, and with sipgate there is
> often echo.

These two are related. Analogue lines have quite bad echo, but because
there is almost no delay, you don't notice it, you hear it as side tone,
which is generally a good thing. The same for TDM circuit switched
connections. (Also I assume for ATM, as it was designed to minimise
latency).

VoIP delays are so high that you do notice the echo, so it has to be
suppressed, at the boundary of the legacy network, for echoes from that
side, or in the phone, for the IP side. I believe it also has to be
suppressed for GSM.

Echo cancellation parameters have to be learned on the fly and without a
guaranteed quiet line in the direction of the echo, rather than the
original signal, so it is difficult to do it perfectly.

The main impact on C21 networks, with respect to latency, was for
analogue modems, for example in social alarms. Some of those couldn't
cope with the additional latency.

[Richmond]

David Woolley <da...@ex.djwhome.demon.invalid> writes:

> On 10/09/2021 15:23, Richmond wrote:
>> it has latency, and with sipgate there is
>> often echo.
>
> These two are related. Analogue lines have quite bad echo, but
> because there is almost no delay, you don't notice it, you hear it as
> side tone, which is generally a good thing. The same for TDM circuit
> switched connections. (Also I assume for ATM, as it was designed to
> minimise latency).
>
> VoIP delays are so high that you do notice the echo, so it has to be
> suppressed, at the boundary of the legacy network, for echoes from
> that side, or in the phone, for the IP side. I believe it also has to
> be suppressed for GSM.

This might be good news because at the moment I get echo reported to me
when I phone landlines with sipgate, but I don't hear it myself,
presumably because the grandstream client suppresses it. When everyone
is on VOIP then it might be suppressed at both ends; at the other end by
ATM.

[Chloe]

On Fri, 10 Sep 2021 07:47:05 -0700 (PDT), notya...@gmail.com

<notya...@gmail.com> wrote:
> On Thursday, 9 September 2021 at 23:34:59 UTC+1, Chloe wrote:
>> On Tue, 7 Sep 2021 07:13:23 -0700 (PDT),
>> notya...@gmail.com <notya...@gmail.com> wrote:
>> >
>> >> Or maybe I could have two networks on the same router?
>> >
>> > Possibly, but I don't know anyone who does it. DT used to provide
>> > analogue, ISDN and ADSL over the same line. For years BT falsely
>> > claimed this was not technically possible.
>> That's because BT's implimentation of ADSL used some of the same frequency
>> range as ISDN, and DT's implimentation didn't.
>>
>> So BT were correct, it was not technically possible on their adsl platform.
>>
>> Chloe
>
> Oh so BT couldn't have used DT equipment on the lines of customers
> who did want both?
>
> BT lied about this and we both know it.
>
> To rub it in BT made their claim when DT doing it was on the front
> page of Computer Weekly.

"BT couldn't have used DT equipment" Correct, DT didn't make any equipment.

I don't know who's system they used, but BT choice was an Alcatel Annex A
adsl dslam and modem combintion.
BT used Annex A, DT used Annex B. Normally to run the different Annex spec
needed a compatible dslam and modem at the client end, doubling the roll out
costs.

Again, BT didn't lie. It was technically impossible with their adsl
implimentation.

"and we both know it" no, you claim it, I gave you the reason. I don't
belive it's a lie because the technical specifications says that's how it
works.

Chloe

[grinch]

snip

> I don't know who's system they used, but BT choice was an Alcatel Annex A
> adsl dslam and modem combintion.
> BT used Annex A, DT used Annex B. Normally to run the different Annex spec
> needed a compatible dslam and modem at the client end, doubling the roll out
> costs.
>
> Again, BT didn't lie. It was technically impossible with their adsl
> implimentation.

BT deliberately avoided ISDN telephony to the home ,they made it
prohibitively expensive. Cisco make/made ADSL routers which support it.

ISDN at home used to give you bragging rights if you had it for work ,I
had it for a year from work but we dumped it when 512k ADSL became
available. Cheaper and faster than ISDN and no call charges.

I am glad I was not paying it. The rental cost was more than double
the line rental for POTS,plus call charges.

I have German relatives which have what we would call ISDN2 at home and
they have DSL over the same copper pair.

My Aunt could never understand why we could only make 1 call at a time
over our telephone system. The had been able to make at least 2 for many
years. Then they got DSL.

>
> "and we both know it" no, you claim it, I gave you the reason. I don't
> belive it's a lie because the technical specifications says that's how it
> works.
>
> Chloe

You are correct, but it was a cost driven choice not at technical one.
ADSL is perfectly possible over ISDN.

[notya...@gmail.com]

On Tuesday, 14 September 2021 at 00:04:13 UTC+1, Chloe wrote:
> On Fri, 10 Sep 2021 07:47:05 -0700 (PDT), notya...@gmail.com
> <notya...@gmail.com> wrote:
> > On Thursday, 9 September 2021 at 23:34:59 UTC+1, Chloe wrote:
> >> On Tue, 7 Sep 2021 07:13:23 -0700 (PDT),
> >> notya...@gmail.com <notya...@gmail.com> wrote:
> >> >
> >> >> Or maybe I could have two networks on the same router?
> >> >
> >> > Possibly, but I don't know anyone who does it. DT used to provide
> >> > analogue, ISDN and ADSL over the same line. For years BT falsely
> >> > claimed this was not technically possible.
> >> That's because BT's implimentation of ADSL used some of the same frequency
> >> range as ISDN, and DT's implimentation didn't.
> >>
> >> So BT were correct, it was not technically possible on their adsl platform.
> >>
> >> Chloe
> >
> > Oh so BT couldn't have used DT equipment on the lines of customers
> > who did want both?
> >
> > BT lied about this and we both know it.
> >
> > To rub it in BT made their claim when DT doing it was on the front
> > page of Computer Weekly.
> "BT couldn't have used DT equipment" Correct, DT didn't make any equipment.

DT provided the equipment and the service on the same line. Who made it is anyone guess and I don't remember BT making their own equipment much after about 1980 (GEC, Marconi, STC, Ericson etc.)

>
> I don't know who's system they used, but BT choice was an Alcatel Annex A
> adsl dslam and modem combintion.
> BT used Annex A, DT used Annex B. Normally to run the different Annex spec
> needed a compatible dslam and modem at the client end, doubling the roll out
> costs.
>
> Again, BT didn't lie. It was technically impossible with their adsl
> implimentation.

Dear oh dear, oh course they could have implemented the same solution as DT for customers who wanted both.

>
> "and we both know it" no, you claim it, I gave you the reason. I don't
> belive it's a lie because the technical specifications says that's how it
> works.

It is a technical specification that BT chose for ALL customers, and they simply would not provide a perfectly viable and working solution for those who wanted ISDN and ADSL - they said it could not be done - when it very clearly could - IMO very easily.

>
> Chloe

[Chloe]

On Tue, 14 Sep 2021 10:46:42 -0000 (UTC),
Roger Bell_West <roger+u...@nospam.firedrake.org> wrote:

> On 2021-09-14, grinch wrote:
>>BT deliberately avoided ISDN telephony to the home ,they made it
>>prohibitively expensive. Cisco make/made ADSL routers which support it.
>

> Think of it more like Concorde pricing in the early 1980s: they made
> it a premium product to get in the sort of people who would pay for
> that little extra bit of performance. Then they were stuck with
> warehouses full of useless ISDN kit when DSL overtook it.

To be fair though, they used ISDN to the home for multiple phone lines by
jamming a pair of adc/dacs into a case and calling it home highway. The
selling point was 2 phone lines, 2 ISDN channels, use any 2. It was cheaper
then 2 phone lines on their own.

I used that from it's roll out for 64kbps till adsl became avalible on my
exchange, as with surftime to remove the call costs, it was able to run as a
nailed up 64/64 line, for much cheaper then the kilostream service BT wanted
to sell for that!

Chloe

[grinch]

On 14/09/2021 18:28, Chloe wrote:
> On Tue, 14 Sep 2021 10:46:42 -0000 (UTC),
> Roger Bell_West <roger+u...@nospam.firedrake.org> wrote:
>> On 2021-09-14, grinch wrote:
>>> BT deliberately avoided ISDN telephony to the home ,they made it
>>> prohibitively expensive. Cisco make/made ADSL routers which support it.
>>
>> Think of it more like Concorde pricing in the early 1980s: they made
>> it a premium product to get in the sort of people who would pay for
>> that little extra bit of performance. Then they were stuck with
>> warehouses full of useless ISDN kit when DSL overtook it.
>
> To be fair though, they used ISDN to the home for multiple phone lines by
> jamming a pair of adc/dacs into a case and calling it home highway. The
> selling point was 2 phone lines, 2 ISDN channels, use any 2. It was cheaper
> then 2 phone lines on their own.

In Germany its the same price for 2 ISDN lines line rental wise ie one
metallic pair but they don't have pots so we really cant compare.

Bottom line BT did not want to covert the telephone network to ISDN due
to the cost,they probably saw VoIP coming and decided not to bother
which is sensible really

>
> I used that from it's roll out for 64kbps till adsl became avalible on my
> exchange, as with surftime to remove the call costs, it was able to run as a
> nailed up 64/64 line, for much cheaper then the kilostream service BT wanted
> to sell for that!
>
> Chloe
>

You are showing your age here ,I remember mega and kilostreams and was
impressed at the time by their speed,at the time not now of course.

[notya...@gmail.com]

BT made ISDN difficult for business and domestic, charging another installation fee on top of the one already paid to convert a line [to Highway].

They stopped doing this when Norweb started offering free ISDN installation, although when I ordered it for my office they took months and dug up Manchester Piccadilly to lay fibre!

Nevertheless it did provide two lines, better call quality (especially through an IDSN phone) and rock solid internet connection, on later kit via USB.

[Brian Gregory]

On 10/09/2021 21:43, Richmond wrote:
> This might be good news because at the moment I get echo reported to me
> when I phone landlines with sipgate, but I don't hear it myself,
> presumably because the grandstream client suppresses it. When everyone
> is on VOIP then it might be suppressed at both ends; at the other end by
> ATM.

If you are using an ATA with an analogue telephone the ATA may not be
very good at minimizing the amount of the incoming call's audio that
gets sent back to the caller. A VOIP telephone connected directly by
Ethernet will probably be better in this respect.