Dan Warne05 September 2006, 3:41 AM
Optus today announced ISPs would be able to begin reselling its ADSL2+ broadband from Q4 this year. But other ADSL2+ networks still have some advantages over Optus...
Optus has announced its wholesale ADSL2+ network will be available in the fourth quarter of this year, providing speeds of up to 24Mbit/s to customers of any ISP that strikes a resale deal with the telco.
ISPs have been frustrated with Telstra's continued refusal to let its last-generation wholesale ADSL network run even at full ADSL1 speed -- 8Mbit/s. Telstra instead runs it at a top speed of 1.5Mbit/s and attaches a premium price-tag to this 'fastest' service.Optus today said it has gone into the last phase of business testing, following the successful technical launch the network on 24 July. 148 exchanges have been enabled for Optus ADSL2+.
However, Optus continues to refuse to provide a list of coverage areas, saying this will be revealed when the service launches to the public. It reiterated that it plans to cover 340 exchanges by the middle of 2007, making it one of the biggest alternate DSL network rollouts in Australia.
Optus has already connected 30,000 of its own customers to the ULL network under the brand "Optus Direct".
Optus would not comment on wholesale pricing, saying it was a confidential arrangement with ISPs and it was up to them to price the service at retail.
However its own Optus Direct ADSL2+ broadband service is good value compared to other ADSL2+ offerings: customers can get a plan with 20GB peak usage + 40GB off-peak usage for $69.95 a month.
Resale pricing by ISPs is unlikely to be any more costly. The pricing is vastly better value than Telstra BigPond, which, for $69.95, offers only 10GB of usage at 512Kbit/s speed -- a fourty-eighth of the maximum speed of an ADSL2+ link.
Optus is now testing the business processes and IT systems involved in its first three ISP resellers -- Internode, Exetel and iSeek Communications -- ordering ADSL2+ connections through the telco.
It said the release of its ADSL2+ network would be a "revolution in the wholesale telecommunications market", offering both ADSL2+ and landline telephony over unconditioned local loop (ULL) -- copper phone lines disconnected from Telstra's network.
"This service will provide the first true alternative to the incumbent’s Local Call Resale service, because Optus Wholesale can provide full featured telephony services over Optus owned infrastructure. There are direct financial benefits from having wholesale customers directly connected to our network," said David Katz, Acting Managing Director for Optus Wholesale.
However, at least one of the initial wholesale customers said off the record it would prefer Optus to allow it to sell ADSL2+ only without also having to resell Optus telephony.
"Different people are coming to us wanting different things, some people want voice only, some want data only and some want both voice and data, so we are trying to tailor the packages to what our wholesale customers are asking for," said Optus spokesperson Simone Bergholcz.
ISPs that buy ADSL2+ through Optus will have the ability to view connection info per customer in real-time directly from the DSLAM line card.
Historically, Telstra's refusal to give wholesale ISPs direct, real-time access to ADSL customer data had been one of the most frustrating aspects of being a wholesale customer of Telstra ADSL, Internode CEO Simon Hackett told APC.
However, Optus said although it would give ISPs access to line monitoring data for each customer, they would not be able to tweak parameters on the DSLAM on a customer-by-customer basis.
Internode, iiNet and other ISPs allow their customers to select their own 'line profiles' -- combinations of settings on the DSLAM which allow for better performance on good quality phone lines, or higher connection stability on noisier lines. APC testing in
"Wholesale customers can monitor [customers' connections] and see noise on the line, but that's it," Bergholtz told APC.
Why iiNet and Internode may still be a better choice than an Optus-based ADSL2+ connection
Extracted from ADSL2+ Modems Megatest: Give your DSLAM a tweak, APC June 2006.
Some ADSL2+ ISPs let you choose “line profiles” for your connection. This is something that Telstra-based ISPs can’t do; Telstra doesn’t allow customers (or even ISPs) to modify any DSLAM settings.
We did all our formal modem testing using the default Internode line profile MAX24 â€" replicating what the majority of customers use.
But to satisfy our interest, we tweaked a few settings here and there â€" what we discovered was staggering: huge performance improvements are made by making tiny changes to settings. (NB: Your mileage may vary depending on the quality of your phone line.)
There are two key settings that can be changed on a DSLAM:
Target SNR â€" tells the modem to aim for a signal-to-noise margin of a certain amount. Expressed in decibels, it’s the difference between the loudness of the modem’s signal and the loudness of background noise on the line.
For each 3dB, the difference doubles, making the connection more resilient to spikes in line noise, but also reducing the maximum attainable line speed. Internode offers a line profile for gamers called “MAX24 â€" HS” which shaves target SNR right down.
People with very good phone lines close to the exchange will get a faster connection. But if there is fluctuating line noise, the connection could be unstable.
Interleaving â€" mixes the packets of data together, along with error-correction data, so if line noise causes packets to corrupt, your modem can recreate them (without the packets having to be retransmitted). Interleaving is described in milliseconds â€" eg. 4ms of interleaving means 4ms worth of packets mixed together.
We discovered during testing [using Internode's Ericsson DSLAMs, which are not the same as the Huawei models being used by Optus] that interleaving can considerably reduce modem performance.
For example, the Cisco 877W modem, which clocked in at the leading speed of 19.1Mbit/s actual throughput with interleaving disabled, lost a full 33 per cent of its speed when we switched interleaving on at the DSLAM. (It dropped back to 19th place at an unimpressive 12.6Mbit/s.) Given Cisco’s rep for speccing its boxes up with enough grunt to handle features being enabled (without performance degradation), this was quite surprising â€" perhaps a sign of immaturity in the 877W’s firmware.
Other modems that suffered the most with interleaving on were LevelOne WBR-3407A (29% drop in performance), Dynalink RTA1335 (27%), Dynalink RTA1046VW (25%) and Draytek Vigor 2800VG (24%).
On average, having interleaving enabled saw performance drop by 17 per cent. However, Internode managing director Simon Hackett says that interleaving plays a very important role on sub-optimal phone lines. “Any packet loss at all can have a huge effect on performance,” he says. “When a phone rings, it’s a 50 volt signal heading down the line; at a low frequency that’s not supposed to interfere with ADSL, but it does produce a broad spectrum impulse spike.
Interleaving does exactly what CD players do; takes data and spreads it over time so if there’s a short spike in line noise (like a scratch on a CD) a number of corrupted packets can be recreated on the fly.”
Indeed, one modem in the test, the low-end Zyxel Prestige 660HW, performed considerably better with interleaving switched on, going from a mediocre 10.5Mbit/s to eighth-fastest â€" 14.5Mbit/s throughput (a 38% boost).
Because interleaving combines a few milliseconds’ worth of data together, which must be decoded at the other end, it affects ping time. This can be a downside for gamers who value fast response in their games.
Given that small settings can make such a major difference, getting the most from your ADSL2+ connection is easiest if you sign up with an ISP â€" such as iiNet and Internode and others â€" that have selectable profiles (usually on their web site once you have logged in to your account settings.)