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G.Inp on Huawei FTTC Cabinet

tiffy
Rising Star
Posts: 119
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Registered: 01-05-2009

G.Inp on Huawei FTTC Cabinet

Have been on fibre for nearly 5 weeks after ADSL conversion.
I am on a Huawei FTTC cabinet and using a G.Inp compatable modem, HG612 running G.Inp compatable firmware.
G.Inp (BT term this retransmission) has not as yet been applied to my line.
I know there is a school of thought that G.Inp is only applied to lines where DLM deems this necessary, however BT's chief engineer would appear to contradict this belief, see kitz interview here, http://www.kitz.co.uk/adsl/ginp-retransmission.htm

My line is performing fully to spec., my DS synch. rate is actually slightly above profile, US rate is as per my contract.
After fibre conversion I was originally on DS fast path, after a few days DLM re-synch'ed to DS interleaving due to high DS ES rate, reverting back to DS fast path again by DLM action 4 days later where I have stayed ever since.
It is a fact that G.Inp will considerably improve DS ES rate without the associated overheads that interleaving causes, ie., decreased DS synch. rate and increased latency.

So what would be the advantage of G.Inp application on my line ?
Line would have a better DS error profile making it unlikely that DLM would intervene in the future and make any changes.

It is my understanding that BT G.Inp (retransmission) is now active on all Huawei cabinets, however, the roll out of revised software to ECI cabinets may still be ongoing.

8 REPLIES
NorthPole
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Registered: 05-07-2013

Re: G.Inp on Huawei FTTC Cabinet

There is some evidence to suggest that BTOR withdrew G.INP support from modems not fully compliant with their SIN498 technical specification just before Easter. This has been claimed to be the reason why many users of the Asus DSL-AC68 reported loss of G.INP on their connection around that time.

tiffy
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Registered: 01-05-2009

Re: G.Inp on Huawei FTTC Cabinet

"NorthPole", many thanks fore the response and the link to SIN498, interesting reading.

I appreciate that the link I included to the kitz interview with BT chief engineer is now 2 years old, there still appears to be many grey areas regarding G.Inp implementation and triggering method, have never managed to get a definitive answer in the short time I have been involved since migration to fibre early June 17, I notice that even PN staff appear to be avoiding this thread, perhaps my fault in appearing to answer my own question in the original post.
Would still welcome a PN staff view !

As stated, I am using a Huawei HG612 modem running unlocked, G.Inp firmware, definately compatable.
Would it be possible for the FTTC cabinet to selectively "ban" some routers/modems as per the issue with Asus models, I would have thought not but I could be wrong, certainly should not be the case with my hardware.

I subscribe to and use the excellent MyDSLWebStats on line facility, here I can see all the current members live & historic router stat's., the vast majority are using Huawei modems (due to their very good stat's. monitoring capability), the only users who have G.Inp inactive or never applied are on ECI FTTC cabinets with the known software compatability issue.
I am currently an exception to this, ie., on a Huawei cabinet with G.Inp not applied. (yet)

NorthPole
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Re: G.Inp on Huawei FTTC Cabinet

tiffy, as you're using a BTOR-supplied Broadcom-based modem connected to a Huawei cabinet I agree that G.INP should surely be supported! As regards the possibility of some Asus modem/routers being blocked by BTOR from using a G.INP connection, I can only assume it's done by chipset detection (the DSL-AC86U has a Mediatek DSL chipset).

tiffy
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Registered: 01-05-2009

Re: G.Inp on Huawei FTTC Cabinet

NorthPole, thanks for your further response.

Ref. the Asus modem/router / G.Inp issue, I suppose it's possible that could be the case, in the absence of any definitive knowledge on this system operation, users experience is probably the best guide currently available, as I have already said, G.Inp implementation is a very grey area even amongst the very informed members of this and the kitz forums.

Can't really blame the PN staff for not commenting, can not imagine that they would be in a position to know any more than the forum members do or indeed have the ability to extract any further information from BT..

I'am still hoping that G.Inp will eventually be applied, some parties in a similar position to myself have waited 6 to 8 weeks from connection for G.Inp implementation so still a chance.
Unfortunately, none of my neighbours who share the same infrastructure have the monitoring capabilities to find out if G.Inp is active on their lines, mostly retirees who don't really care what's happening as long as the I-Player is working, not a criticism I hasten to add, it's the view of the vast majority of BB users, we can't all be geeks !

NorthPole
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Re: G.Inp on Huawei FTTC Cabinet

tiffy, I share your frustration. My own router stats. show 177 CRC errors downstream and 61 upstream over an 11 day period; even if every CRC comprised an individual ES, the figures seem surely good enough for DLM to allow G.INP correction rather than the present Interleaving.

tiffy
Rising Star
Posts: 119
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Registered: 01-05-2009

Re: G.Inp on Huawei FTTC Cabinet

"NorthPole", by observation of subscribing members on the MyDLSWebStats site who are currently running with G.Inp applied (all on Huawei FTTC cabinets) it appears that DS interleaving is in service also but to a fairly low depth, appears to be a by-product of G.Inp, however, there does not appear to be any DS synch. rate loss which is normally associated with interleaving.
I don't believe there is any, or as much latency increase also associated with DS interleaving application but obviously can not tell from stat's. observation on the MDWS site.

I can also observe the before and after effect of G.Inp implementation on subscribers lines from their historic data, the decrease in DS ES rate is quite dramatic.

Community Veteran
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Re: G.Inp on Huawei FTTC Cabinet

There's no fixed and constant increase in latency or significant loss of bandwidth associated with retransmission, but there would be delays and loss of throughput varying with how much data actually gets re-transmitted. It's not reported in the "sync rate", but the IP Profile does tend to be a lower percentage of the "sync speed" on "Retransmission High" profiles (probably because it's using the ETR instead of the "sync speed", and it's making allowances for the expected loss of throughput caused by re-transmitting data).

tiffy
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Posts: 119
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Registered: 01-05-2009

Re: G.Inp on Huawei FTTC Cabinet

"ejs", many thanks for the additional information ref. G.Inp (retransmission), if ever enabled on my line I should get the chance to observe these changes on my MDWS stat's., still waiting, 5 weeks since fibre migration today.