[LINK] Australia Gets Broadband – A Slow Connection For A High Price
rchirgwin at ozemail.com.au
rchirgwin at ozemail.com.au
Mon Jul 16 06:49:04 EST 2007
The reference wasn't direct at Janet, but at the article. Janet didn't
write the article, so I don't see how my remark should reflect on my
attitude to Janet.
Now. Deferring to Glen Turner's expertise, but I can't see any country
in which consumer broadband is provisioned on a 1:1 basis; so to
criticise Telstra's 8 Mbps service as "not guaranteed" is silly. That
part is mere anti-Telstra kneejerk on the part of the writer.
steve jenkin wrote:
> Richard Chirgwin wrote on 13/7/07 5:36 PM:
> Calling Janet's comment, and by inference her, 'stupid' is offensive and
> uncalled for - especially on the very first post in a thread. It
> doesn't progress any debate, inform or educate anyone and it's a
> positive dis-incentive for others to post.
> Your turn of phrase diminishes the whole of the LINK list.
> Especially when what you post:
> - is ambiguous and undefined
> - incorrect in many senses
> and you confuse different concepts.
>> Eeeek! What a shockingly stupid statement.
>> 256 Kbps is a best-effort service.
>> 512 Kbps is a best-effort service.
>> 8 Mbps is a best effort service.
> Remember Frame Relay? [No, I'm *not* saying ADSL services provided by
> ISP's is 'Frame Relay']
> It's got a couple of key concepts that apply to ADSL services:
> - Access Rate - the signalling rate on the customer tail
> - Committed Information Rate - the min. bandwidth guaranteed at all
> times to customer by the service provider
> The Access Rate is strictly on the link from the customer premises to
> Exchange/Network Access Point.
> The CIR is an end-to-end rate across the full Service Provider network.
> Telco and ISP's provision services with an 'over subscription' rate [or
> number of times over subscribed].
> This applies at the Telco/ISP network level - links overseas,
> interconnects and even DSLAM links back to the ISP's backbone network.
> Janet was quite clearly saying that Telcos will only guarantee for ADSL
> a line or access rate, that's the signalling rate from customer premises
> to DSLAM, up to 1.5Mbps if you are no further than about 8km from the DSLAM.
> None of this references line-errors or link throughput - nor the
> stability/usability of the service.
> Telco's offer a higher rate service, that Janet was referring to, with a
> non-guaranteed signalling rate and a potential maximum profile of 8Mbps.
> [If fact, ADSL or ADSL2+, they will only guarantee 1.5Mbps].
> On top of different rate plans, Telcos, e.g. Internode, offer a range of
> different ADSL profiles varying in speed (upload/download), stability
> and latency. They generally have one referred to as 'Thrillseeker'.
> Janet used the term 'best effort' to describe the non-guaranteed nature
> of the ADSL customer-loop above 1.5Mbps.
> It wasn't misleading or confusing...
> You've switched from talking about the customer-line access rate
> (Janet's area) to realised Network Throughput.
> And used a term, 'best effot' that probably isn't in any contract or
> technical description.
> And the rate a customer can realise varies wildly, depending on their
> location in the network, the remote end location and the network path
> - we talking upload/download?
> - local, intracity, intrastate, international, ...
> - 'On Network' for the ISP
> - via peering services
> - time of day, events, ...
> All of these are affected by interference, lost packets, routers,
> congestion, temporary equipment/link failures, ...
> And then there's the crux of the matter - the server you're talking to
> and protocol stacks you're both using.
> If it's a dog and runs incredibly slowly, then nothing in the network
> will help.
> The IP protocols themselves guarantee nothing...
> There are a bunch of RFC's that define "Quality of Service" and related
> network management and performance issues.
> Any IP-based network can make very few guarantees, especially on busy
> Google spend a lot of time and effort dealing with strange network and
> routing problems every day. But to everyone it still appears 'To Just Work'.
> So when you say "Best Effort" without clarification, it doesn't show any
> knowledge or appreciation of the field.
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