cancel
Showing results for 
Search instead for 
Did you mean: 

PPOE versus PPOA and two modems on one ADSL line

shermans
Aspiring Pro
Posts: 1,099
Thanks: 38
Fixes: 3
Registered: 07-09-2007

PPOE versus PPOA and two modems on one ADSL line

I spend a lot of time in France, as some may know, and most of that time is spent complaining about France Telecom, a.k.a. Orange, a.k.a. State Monopoly !  Trying to get even basic customer service just results in the Gallic Shrug, let alone trying to get any information.
When I first set up my ADSL some time ago, I was instructed to use VPI/VCI 8.35 in France instead of the UK .38 which is fine.  I don't know what it means but it appears to be the French standard.  But I was also instructed to use PPoE, whereas Plusnet uses PPoA.  I do not know  the difference.
The ADSL service is called "Stretched 512" , which I have been told is a protocol which is outlawed in the UK - I am two miles from the exchange and 512k is the best I can get.  I understand that the signal somehow gets "boosted".  But the consequence is that the service is poor and has been getting poorer.
I use Internet Radio all the time to keep in touch with things in the UK and listen to the BBC.  The trouble is that the Internet Radio is always dropping out, even though the internet connection itself remains available on the laptop for websites.  The Internet Radio is a Logic  IRMA 1 using the Reciva service.  It works well so long as there is a signal, but I often get "Low Signal" messages.
I have been experimenting and thought that I might try changing from PPoE to PPoA to see what happened.  I do not pretend to understand the difference, but I read by Googling that PPoE uses the resources of the hardware, whereas PPoA uses the resources of the modem router.  That seems plausibly the reason why the Internet Radio drops out while the laptop can still access the internet.  I have changed the setting on the router and at least it still works.  Could I be onto something, or is this not likely to make any difference ?
The other thing I thought about was whether it might be possible to use a dedicated WiFi modem for the Internet Radio rather than sharing it with the laptop.  That would mean having two modems on one ADSL subscription.  I imagine that is impossible, because presumably they would clash with on another and not synch.  Is that correct ?
Any suggestions or answers would be most welcome.
6 REPLIES
shermans
Aspiring Pro
Posts: 1,099
Thanks: 38
Fixes: 3
Registered: 07-09-2007

Re: PPOE versus PPOA and two modems on one ADSL line

Some seven hours later having changed from PPoE to PPoA, the Internet radio has not dropped out at all.  It seems that it has fixed it, but does anyone know why ?
VileReynard
Seasoned Pro
Posts: 10,980
Thanks: 265
Fixes: 11
Registered: 01-09-2007

Re: PPOE versus PPOA and two modems on one ADSL line

Because pppoa uses ATM packets which are small and include extra error detection/correction?

Superuser
Superuser
Posts: 9,768
Thanks: 1,151
Fixes: 63
Registered: 06-04-2007

Re: PPOE versus PPOA and two modems on one ADSL line

I think in the UK at least on ADSLx PPPoE is actually transmitted to the modem as PPPoEoA. There is extra overhead with PPPoE but I wouldn't expect that to cause the transmission to drop out. Perhaps the modem/line card combination doesn't handle PPPoE too well.
The more technically minded might be interested in blog On PPPoA, PPPoE, ATM and ADSL.
David
prichardson
Grafter
Posts: 1,503
Thanks: 1
Registered: 05-04-2007

Re: PPOE versus PPOA and two modems on one ADSL line

I have never heard of "Stretched 512" and there are certainly no documents in the wild that reference it in any way that I can see.
They may have mean G.Lite, which is an extension of ADSL recognised by the ITU as G.992.2.
http://en.wikipedia.org/wiki/G.992.2
This is in use in the UK by BT and came into operation before fixed 2Mbps home services were made available. From BT it's called raADSL (Rate Adaptive), though I doubt there is anybody in the support centre that would know anything about it, as there is absolutely no support difference between G.992.1 & G.992.2.
shermans
Aspiring Pro
Posts: 1,099
Thanks: 38
Fixes: 3
Registered: 07-09-2007

Re: PPOE versus PPOA and two modems on one ADSL line

Well, actually it was you who told me last April that it is outlawed :
Quote from: P
RE-ADSL, or ADSL2 Annex L (not ADSL2+) is not supported in the UK.
http://en.wikipedia.org/wiki/G.992.3_Annex_L
Due to the cross-talk it can introduce, it is (or at least wasn't as of September 2011) not licensed under the ANFP (Access Network Frequency Plan)

Apparantly it is called "Range Extended" in English - the French translates as "Stretched 512".
Anyway, that is the service I get and it is lousy !!  It seems to work better on PPoA but the Internet Radio has dropped out a couple of times today even on PPoA, but it may be for a shorter time while it buffers again.  The radio is running 127kbps MP3 format streaming from Reciva.
prichardson
Grafter
Posts: 1,503
Thanks: 1
Registered: 05-04-2007

Re: PPOE versus PPOA and two modems on one ADSL line

Ahh, that will be why then. It was the lack of online reference to the specific term they used.