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Guspaz
Guspaz
Premium,MVM
join:2001-11-05
Montreal, QC
kudos:23
reply to TSI Paulo

Re: Question about 100MB business fiber

said by TSI Paulo:

As with any PPPoE, you'll need to take into account the 15-20% overhead with the connection. For example, yesterday I set a customer up with a 4 line 25/7mbs MLPPP connection and they were getting 89mbs down and 26mbs up.

There is no effective overhead on VDSL2 service, because Bell sets the sync speeds higher than the advertised speed in order to account for overhead. A single 25/7 line sees actual throughput in speed tests of 25/7, and so that particular customer should be seeing 100 mbps down, and 28 mbps up.

26 is close enough to 28 that you could write it off as margin of error, but 89 mbps indicates some problem (non-optimal mru perhaps?).
--
Developer: Tomato/MLPPP, Linux/MLPPP, etc »fixppp.org


TSI Paulo
Premium
join:2011-09-28

I was thinking the same thing given profiles are set higher than the 25/7. We typically set the MRU/MTU to 1480 but perhaps dropping the MRU to 1460 would optimize this connection.



Guspaz
Guspaz
Premium,MVM
join:2001-11-05
Montreal, QC
kudos:23

Actually, now that I think about it, VDSL2 doesn't use ATM, so the rules about optimal MRUs aren't the same as they were for ADSL... Back in the day, you had to set it correctly to avoid wasting ATM cells, like if your pppoe frame was just one byte over the limit, it would require an entire extra ATM cell... But that's not the case anymore, so my comments may not apply.
--
Developer: Tomato/MLPPP, Linux/MLPPP, etc »fixppp.org


scorpido
Premium
join:2009-11-02
New Hamburg, ON
kudos:1

PM Me and I can put in contact with a guy who an do better then $1200. Believe me, I know.



TSI Paulo
Premium
join:2011-09-28
reply to Guspaz

Thanks for updating Guspaz. Your input is always appreciated. I'm not sure what could be causing the bottleneck if there is one. I'll do a bit of research and try to figure out what it could be I suppose.

Paulo



Guspaz
Guspaz
Premium,MVM
join:2001-11-05
Montreal, QC
kudos:23

Basically consider that the sync speed for 25 meg DSL is about 26.95 megs, so your customer is actually seeing 89 meg throughput on a ~108 meg aggregate sync. Overhead on VDSL2 seems to be roughly 6-7% (going from benchmarks here, not doing the math). ATM was one of the biggest sources of overhead with ADSL, and that's gone now, hence the lower overhead. So if he's seeing 89 meg, that's about 17% overhead, way more than we'd expect to see.

Although there is also some MLPPP overhead too, of course, but that was like 0.4%.
--
Developer: Tomato/MLPPP, Linux/MLPPP, etc »fixppp.org