A new way to handle noise on Openreach FTTC based lines has been rolling out for a while now and while the promise was great, i.e. some extra speed and error correction without the latency impact of interleaving the reality is a little different.
We believe the great majority of people have noticed no negative impact from G.INP (ReTx) and some are certainly pleased with the extra speed they believe they have gained. Alas not everyone is happy, some are seeing extra latency with AAISP reporting 15ms extra in some cases (which when a non-interleaved FTTC line can see latencies of 7 to 8ms is a big change) and some people with ECI modems (supplied by Openreach or sourced themselves) have found their speeds drop.
- Retransmission hasn’t been rolled out to our ECI estate yet, although we do have 9,000 ECI lines running under trial conditions and a full roll-out is being considered.
- We understand that some people may retain old hardware as a ‘back-up’, but there is a risk associated with that once a ReTX policy has been applied. Such units will not immediately reference the correct compatible firmware, so will fail to synchronise when connected to the line.Comments on G.INP from Openreach
Openreach did express some surprise when we pointed out that people had at times being supplied with an ECI modem in a Huawei cabinet area when engineer installs were the norm. We suspect that many of the problems reported where ECI hardware is used is down to things like this, the Huawei HG612 modem was always the more popular device with the tech savvy as it was easy to unlock and thus allow people to track the line stats.
ECI modems need a firmware upgrade to work with G.INP and the way this should work is that ECI hardware connected to a ECI cabinet will see the firmware update pushed to the modem before G.INP is turned on. Of course if someone is away on holiday for a couple of weeks, or the hot-spare modem that a home worker might keep will not see this firmware update and at this time what would happen is that the modem simply refuses to sync. It has been reported on our forums that a DLM reset will resolve the problem and push the new firmware once more, but apparently this is not the correct procedure for providers to use with Openreach saying 'the ISPs should be aware of this and how to deal, because the product spec was communicated and the effect on some lines anticipated'. So what exactly is the correct procedure we don't know - maybe a trade secret.
BT Home Hub 5 Type A is another device that is reported to suffer problems in terms of connecting at slower speeds after G.INP is enabled, with the Type B working perfectly. Some other third party hardware may need firmware updates too to benefit from G.INP but it is easy for people to download the file and update a routers firmware, worst case you have to visit a public Wi-Fi hot-spot to download the firmware.
Those who were involved in the original 2000/2001 ADSL roll-out remember similar pain over firmware updates with the original locked down hardware and we are sure that Openreach is looking forward to the day when it can effectively stop supporting millions of VDSL2 modems, but while the range of third party hardware is increasing the choice is still limited and people may be hesistant to spend large sums when vectoring support is still a bit of an unknown. Popular combined VDSL2 modem/router options appear to be the Billion 8800 NL at £67, Billion BiPAC 8800 AXL at £132 (802.11ac dual band) and the 802.11ac Asus DSL-AC68U at £170 (the Asus is believed to need a firmware update to work with G.INP). The high price tags commanded by the better devices show why the third party trade in Openreach modems is so large as cheaper and router options result when you just need an Ethernet WAN port.
Perfect world, ECI would make available a way of getting the G.INP compatible firmware onto their hardware other than it being pushed out by Openreach. The winners are probably going to be those on eBay selling the HG612 modems.