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Author Topic: Swapping OR Modems - results....  (Read 14465 times)

Bestgear

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Swapping OR Modems - results....
« on: March 06, 2013, 08:18:11 PM »

Guys

I just thought I would share my results from playing around with three variants of the OR modem.

My Infinity was installed with the ECI b/r. I got a stable 64mb down and 14 up.

I bought a ECi B/I rev B - swapped it out and it performed very slowly - even though the upload and download MB and latency was as low as before - BUT - any browsing was deathly slow with frequent time outs on many sites - just lik eyou get when theMTU is wrong (obvioulsy not changed). I unlocked it and it was the same (no surprise) - tried it on a friend line and it was 100% perfect - go figure!

I also bought a good old HG612 - thinking want to see stats and all round more friendly.

Boy - what a shocker - I lost 11mb of download speed and upload was 1mb higher!! A couple of days later my IP profile finds its way down to 53mb or so.... AGH!!!!

I also configured it as a router (rather than having my 1841 do PPPoE) and it works very well - I can only wonder why BT did not sell/provide an all in one modem router solution (obvioulsy model LAN ports and wireless). Thinking here is that if the 612 router was ok as a basic firewall, loosing more kit saves power (have a few separate APs to cover the house).

I appreciate the the later ECI is seen as the best modem in terms of line condition handling - but what i saw was considerable to the point that it *must* be beneficial for 612 owners to go try a later ECI.


Any and all comments on the above plus your own experiences most appreciated.

BG
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NewtronStar

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Re: Swapping OR Modems - results....
« Reply #1 on: March 06, 2013, 08:41:29 PM »

My thinking is that your FTTC Cab hardware should be matched to the same Modem hardware
IE: Huawei Cab to HG612 and ECI Cab to ECI modem, but your tests seem to confirm this myth.
« Last Edit: March 06, 2013, 08:45:04 PM by NewtronStar »
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Bestgear

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Re: Swapping OR Modems - results....
« Reply #2 on: March 06, 2013, 09:09:04 PM »

Hi

Well... I need to go for another look, but I sure my cabinet is not an ECI one.....

It does make me wonder why the b/i was so ponderous...


BG
« Last Edit: March 06, 2013, 09:27:19 PM by Bestgear »
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Bestgear

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Re: Swapping OR Modems - results....
« Reply #3 on: March 06, 2013, 09:26:52 PM »

Can you tell what cabinet I am on from this ?

Code: [Select]
Status: Showtime
Retrain Reason: 2
Max:    Upstream rate = 15701 Kbps, Downstream rate = 52680 Kbps
Path:   0, Upstream rate = 14999 Kbps, Downstream rate = 53308 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
       VDSL Port Details       Upstream        Downstream
Attainable Net Data Rate:      15701 kbps         52680 kbps
Actual Aggregate Tx Power:        6.8 dBm          11.8 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB):  6.0     30.6    45.8     N/A    15.3    38.0    58.7

Signal Attenuation(dB):  6.0     29.9    44.6     N/A    15.3    38.0    58.7

        SNR Margin(dB):  6.4     6.5     6.4      N/A    5.8     5.8     5.8

         TX Power(dBm): -4.0    -11.9    6.4      N/A    8.5     7.8     4.0
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asbokid

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Re: Swapping OR Modems - results....
« Reply #4 on: March 06, 2013, 09:34:14 PM »

Can you tell what cabinet I am on from this ?

Code: [Select]
Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)

From the bandplan, you're on a Huawei DSLAM.  See Bald_Eagle's (Paul's) research here:

http://forum.kitz.co.uk/index.php/topic,11002.msg215116.html#msg215116

cheers, a
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Bestgear

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Re: Swapping OR Modems - results....
« Reply #5 on: March 06, 2013, 09:43:00 PM »


From the bandplan, you're on a Huawei DSLAM.  See Bald_Eagle's (Paul's) research here:


cheers, a

Thats great, thanks...so much for ECI only working better on a ECI cab then!
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asbokid

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Re: Swapping OR Modems - results....
« Reply #6 on: March 06, 2013, 10:20:42 PM »

When some kit arrives, a few tests are planned on the half dozen VDSL2 modems to hand. The idea is to discover which modem/s perform best under various adverse conditions (loop length i.e. attenuation and background noise).  Others have reported that the Lantiq chipset in the ECI performs well on shorter loops but not so good otherwise.  Or at least that was the finding with ADSL2+, but maybe performance is different for VDSL2.    It would be nice to answer that categorically.   Certainly the Lantiq isn't as sensitive as the Broadcom chipset, even on the shortest loops. [1]  It doesn't obtain such a good SNR margin under the same conditions.

cheers, a

[1] http://insidehuaweima5616msan.wordpress.com/2013/02/26/contrasting-zero-loop-stats-for-eci-i-revision-and-r-revision-vdsl2-modems/
« Last Edit: March 07, 2013, 12:12:19 PM by asbokid »
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Bestgear

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Re: Swapping OR Modems - results....
« Reply #7 on: March 07, 2013, 12:28:24 PM »

The idea is to discover which modem/s perform best under various adverse conditions (loop length i.e. attenuation and background noise). 

Is there a quick way for me to find the loop length?

I assume the standard Bt line test is the whole path to exchange not to cabinet.

BG
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asbokid

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Re: Swapping OR Modems - results....
« Reply #8 on: March 07, 2013, 02:51:42 PM »

BT has its own infrastructure records, and the LLU OLOs have access to them too. 
Some DSLAMs also have a loop length estimation tool (as part of their line testing tools - SELT/DELT/MELT).
The loop length estimation function in the Huawei DSLAM firmware doesn't seem to be very accurate.

Otherwise, time domain reflectometry equipment is needed.  A TDR (pulse echo sounding) is used to discover the distance to the DSLAM transceiver, whether that is in a street cabinet or the exchange.

cheers, a
« Last Edit: March 07, 2013, 03:00:03 PM by asbokid »
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Bestgear

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Re: Swapping OR Modems - results....
« Reply #9 on: March 07, 2013, 09:10:41 PM »



Otherwise, time domain reflectometry equipment is needed.  A TDR (pulse echo sounding) is used to discover the distance to the DSLAM transceiver, whether that is in a street cabinet or the exchange.

cheers, a

I was hoping that there would be some info buried we could read and get that!

I have a mate that works in BT, so could ask him to use his JDSU which I assume will show the length.

I assume its only the home to cabinet distance we need... the fibre run will be irrelevant.

I have moved back tot he later ECI today and wham...11mb higher throughput.

I am surprised that my reported IP profile adjusts dynamically - or very quickly (overnight it seems to discon and recon at a different rate if I have been playing around) - is this normal?!?! I am lucky it does!

I was please too that the 612 seems to be perfectly capable of sustaining throughput when setup as a router even with simple firewall and nat enabled - I feared these would flatten the box. I am back to using the ECI and an 1841.


BG
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NewtronStar

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Re: Swapping OR Modems - results....
« Reply #10 on: March 07, 2013, 09:45:55 PM »

I'll stick to my HG612  ;) on my longer loop, though if you wanna send me an unlocked ECI modem ill be very happy to test it out  :)
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Bestgear

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Re: Swapping OR Modems - results....
« Reply #11 on: March 08, 2013, 08:08:12 AM »

I'll stick to my HG612  ;) on my longer loop, though if you wanna send me an unlocked ECI modem ill be very happy to test it out  :)

What do you class as a longer loop?

I suspect I will be circa 400m to cabinet but should get that confirmed soon.

From my experience of 612, early and late modems, the later eci outperforms all that have gone before it...YMMV of course....
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asbokid

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Re: Swapping OR Modems - results....
« Reply #12 on: March 08, 2013, 10:17:48 PM »

Some more tests were done this evening.. The results are as follows:





(click for full size)


The raw data is attached:

cheers, a

« Last Edit: March 09, 2013, 09:35:17 PM by asbokid »
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NewtronStar

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Re: Swapping OR Modems - results....
« Reply #13 on: March 09, 2013, 12:49:14 AM »

absolutely fabulous asbokid and thanks for those results, I guess thats why i was given a HG612 being 725 meters from cab.
« Last Edit: March 09, 2013, 12:53:06 AM by NewtronStar »
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asbokid

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Re: Swapping OR Modems - results....
« Reply #14 on: March 09, 2013, 08:16:27 PM »

The results are surprising and the reverse of what was previously understood from ADSL.

The Huaweis (all Broadcom-based) outperform on the shorter loops, but lose out to the Lantiq (and the Ikanos-based Sagem F@st2764) in the longer loop scenarios. for VDSL2.

The loop lengths are indicative but are somewhat arbitrary.   Ideally, the tests would encompass wider ranges of attenuation.    Artificial local loops created from variable attenuator blocks would be needed to simulate this.

It's nice to see the giant Broadcom Corporation is getting a run for its money. And its competitor Lantiq, a private-equity spin-off from Infineon, is nominally European, to boot.

Although Broadcom is just about to release two new System-on-Chips (SoCs).  These are the BCM63168 and the BCM63268.     The Product Brief for them, is, erm, very brief, but details a PCIe architecture whereas the BCM6368 supports just PCI.   Otherwise, at least on paper, everything else looks the same.  Whether performance in the field is improved will be interesting to see (and to test!)

cheers, a

« Last Edit: March 10, 2013, 01:41:13 AM by asbokid »
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