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raytaylor:hio77: While g.fast wont make too much difference in NZ, the use of vectoring, on vdsl would be quite nice.
G.INP would be nice too.
I went to a presentation at chorus' office in wellington where they had an alcatel lucent rep there who told us about the vectoring feature they are introducing.
The goal of vectoring is to both increase throughput and reduce crosstalk between copper loops in the same cable or nearby cables.
At the time there were some serious limitations on how you can implement it.
- DSLAMS need to be interconnected with a vectoring control cable.
- Copper pairs need to be connected to the same network of DSLAMS in the cabinet or central office.
The problem - we have unbundling in New Zealand.
That means the fancy vectoring dslam that chorus may install cannot tell what the ZyXel dslam of ISP-X is doing, which may also be feeding some copper pairs in the same trunk cable going down a street.
So there will be some crosstalk reduction, but unbundling does limit its effectiveness
Yeah, unbundling is an issue in terms of effectiveness, however i do recall a few whitepapers which showed a sizeable improvement on things, with even 50% of lines in a bundle vectored.
Given this graph is a simplified case, and Multiple DSLAM on a pair, affect differently to a single DSLAM with only half the lines vectored, but an interesting read none the less.
for cabinets, ild expect ULLC would be almost a null issue, and at a guess 20%? on an exchange
Atlest based off whitepaper reading alone, i see that as reasonable.
networkn:
I'd also love to know the answer to this. Can I petition, beg, borrow, steal, bribe, blackmail, guilt trip or in any other manner, increase my chances of getting one of said cards or having my card upgraded if it's not one presently?
I am not quite willing to give my first born child, but almost anything else could be negotiated :)
no longer will just dodgy line profiles be a thing! there will be dodgy attempts to get the 100mbit line cards!
Chorusnz: We don't have any plans for VDSL 30a. It's not that popular overseas so not all modems and line cards support it. Our current focus is on implementing VDSL Bandplan 998 which more efficiently uses frequencies up to 17MHz. This should provide most VDSL customers with a decent speed increase without having to replace modems.
Chorusnz: Results from the 998 field trial were very positive. Average downstream speed improved by about 50% (from 35.0 to 52.4Mbps). Average upstream also improved by about 30% (from 9.6 to 12.8Mbps). The normal caveats apply i.e. there are a lot of factors that can influence VDSL speeds on an individual line, so not everyone will get the same level of improvement. In terms of max speed, those with best of all factors (short loop length, right equipment, right premise wiring, etc.) can get up to 70Mbps or 100Mbps. The difference depends on the type of VDSL line card we have in our DSLAM. Early generation line cards, typically in urban areas, can get up to 70Mbps. Newer generation line cards, typically in rural areas, can get up to 100Mbps. We’re currently analysing how far we can extend minimum range and hope will announce any change once field test results are analysed. One of the benefits of 998 is that it uses a very low frequency band (known as US0) for upstream which supports sync and stability on longer lines. Once we’ve got approval from the industry via the TCF and the commerce commission, we’ll do a phased rollout across the network and update the pre-qual threshold. All by Christmas.
This all sounds very exciting.
The point on average upstream increase is rather interesting considering 8b spectrum allocation for upstream.
Would it be possible to expand on the statistics in terms of 8b vs 17a lines? Ild find the figures there rather interesting.
Based off the lines i have seen, indeed 17a does look to be being used more efficiently which is great to see!
Considering your point about looking to expand things, and making more effective use of the 17a spectrum, is it likely that 17a is going to be pushed out to its upper limit a little more?
The use of US0, particularly on a longer line, is great to see. Certainly does make up for the loss of spectrum a little in 8b upstream too.
out of the 998 lines, there seems to be a common theme of 17a lines having 12dB target snr, while 8b lines having a target snr of 9db. Is this going to be the new default difference between the bandplans?
Are there 12dB "Stability" profiles for 8b should DLM decide its needed in there?
