Question about distance from the exchange

Forums › New Zealand Broadband › Question about distance from the exchange

c3rn

291 posts

Ultimate Geek
+1 received by user: 21

#22801 8-Jun-2008 21:39

Gotta question about ADSL2+ in regards to what kind of speeds I will can expect. I have the email below from telecom:

ADSL line check for 9298****
Should be OK for service.
Distance: 2948m
db: 76
Ohms: 809
Loading coils: 0

(Distance to PAK/CS cabinet: 451m, 12dB, 124Ohm).

Question 1: Does this mean my distance from the exchange is 2948m or 451m

Question 2: With this in mind, does anyone know what kind of speeds i can expect with an ADSL2+ service?

1 | 2

29 posts

Geek

#136537 8-Jun-2008 21:51

I'm just guessing here, so don't shoot me if i'm wrong ;-)
In my opinion you're on a roadside cabinet, (PAK/CS) of Pakuranga exchange. You're about 451m from that cabinet. What I don't understand are the dB values, they seems to be quite on the high side. Regardless of that - you should get near the max speed on ADSL2+.

cyril7

9073 posts

Uber Geek
+1 received by user: 2499

ID Verified

Trusted

Subscriber

#136590 9-Jun-2008 07:51

It would indicate your full line length is just on 3km, so you should get 6-7Mb/s on ADSL1 and similar on ADSL2+. Cabinet PAK/CS is scheduled to be upgraded (cabnetised to ADSL2+) in August 2009, which means as you are 450m away from it you should expect speeds north of 20Mb/s.

Cyril

c3rn

291 posts

Ultimate Geek
+1 received by user: 21

#136604 9-Jun-2008 08:52

Fantastic! Really hope I can get speeds above 15Mbps.

@ pshemko - I live in Papakura not Pakuranga.

cyril7

9073 posts

Uber Geek
+1 received by user: 2499

ID Verified

Trusted

Subscriber

#136610 9-Jun-2008 09:11

Dont forget that you will not get speeds above 5-7Mb/s till the cabinet is upgraded, which as I say is penned in for Aug09.

Cyril

olof

154 posts

Master Geek
+1 received by user: 50

Trusted

One NZ

#136629 9-Jun-2008 10:36

I am not sure if the cabinet is electrical with a DSLAM or not. However, the expected speeds for the two distances are as follows:

*** 2948m: ==> approx 5Mbps (DSL)
*** 451m: ==> approx 17Mbps (DSL)

Both speeds are lab measurements with disturbers. (The disturbers simulates the other DSL subscribers that are on teh same cable sheath as you are.)

Please note that the above speeds are the ADSL line rates, and not the IP level rates that you will achieve (for downloads etc). ADSL2+ in NZ is using the following protocol stack: IP over PPP over RFC2364 over ATM over ADSL or ADSL2+. The PPP and ATM encapsulations add ~ 15% overhead. In other words, your expected IP level speeds are:

*** 2948m: ==> approx 4 Mbps (IP)
*** 451m: ==> approx 14 Mbps (IP)

I am writing a blog post series on ADSL speeds. First post here.

Caveat emptor: a lot of factors play in for speed. The above estimates are still somewhat theoretical. YMMV.

Olof Olsson - my views are my own.

xpd

Geek of Coastguard
14115 posts

Uber Geek
+1 received by user: 4574

Retired Mod

ID Verified

Trusted

Lifetime subscriber

#136872 10-Jun-2008 08:50

brad_p:

Question 2: With this in mind, does anyone know what kind of speeds i can expect with an ADSL2+ service?

I was told last week after some ADSL issues, that my line is capable of supplying me with 12mbps - Im exactly 2k from the exchange.

XPD / Gavin

LinkTree

Samsung

Shop now on Samsung phones, tablets, TVs and more (affiliate link).

olof

154 posts

Master Geek
+1 received by user: 50

Trusted

One NZ

#136894 10-Jun-2008 09:26

Brad:

At 2km from the exchange, you are looking at 9Mbps DSL2+ line rate with disturbers. 12Mbps would be theoretical.

With 9Mbps line rate, you should be able to achieve 7.7Mbps IP rate (= effective download rate/speed meter rate). (~15% ATM/PPP encapsulation overhead.)

Let me know what you get once it has been installed! Always interesting to compare "theoretical" with practical.

Olof Olsson - my views are my own.

pshemko

29 posts

Geek

#136975 10-Jun-2008 12:19

@olof,

so, what do you make of the following:
1. Distance from the exchange - 1.7km (attenuation of 21-22dB, new wiring, gauge 0.4mm)
2. ADSL2+ sync speed between 18.5 and 20M
3. Actual speeds - up to about 16Mb/s

cyril7

9073 posts

Uber Geek
+1 received by user: 2499

ID Verified

Trusted

Subscriber

#136979 10-Jun-2008 12:25

Your figures are on par if not better than average for the line length. I presume the 16Mb/s is actual tested download speed from the likes of speednet etc.

Cyril

pshemko

29 posts

Geek

#136992 10-Jun-2008 12:55

Yes, that's actual speed I'm getting downloading things (for example from ftp.citylink.co.nz).

I think that on 2km line you should be somewhere between 15 and 17M sync.

olof

154 posts

Master Geek
+1 received by user: 50

Trusted

One NZ

#137005 10-Jun-2008 13:43

Pshemko,

It is pretty amazing that you are getting 18-20M connect speed at 1.7km. It is certainly in contrast to lab tests with disturbers. (Did you lay the copper between your house and the exchange yourself :-). Even most vendor supplied "theoretical" speeds would have you at lower speeds. Good on ya!

Are you sure that you are not served off a cabinet closer to your premises?

Olof Olsson - my views are my own.

Samsung

Shop now on Samsung phones, tablets, TVs and more (affiliate link).

pshemko

29 posts

Geek

#137024 10-Jun-2008 14:32

I did a bit of searching and found the following graph:
http://adsl.yesyes.info/modules/xoopsfaq/index.php?cat_id=2

It is based on Australian deployment (internode), but it actually matches my results too.

And I'm definately not on a road side cabinet (I've been migrated onto VF 'red' network)

cyril7

9073 posts

Uber Geek
+1 received by user: 2499

ID Verified

Trusted

Subscriber

#137026 10-Jun-2008 14:42

olof, cast your eyes down this page here and I think you will soon realise that the published speeds you have been referencing are very conservative, then again, the linked page does not indicated if these connections were significantly stable or not.

Cyril

lonney

85 posts

Master Geek

#137035 10-Jun-2008 15:01

Here is a nice graph

c3rn

291 posts

Ultimate Geek
+1 received by user: 21

#137161 10-Jun-2008 21:03

olof: Brad:

At 2km from the exchange, you are looking at 9Mbps DSL2+ line rate with disturbers. 12Mbps would be theoretical.

With 9Mbps line rate, you should be able to achieve 7.7Mbps IP rate (= effective download rate/speed meter rate). (~15% ATM/PPP encapsulation overhead.)

Let me know what you get once it has been installed! Always interesting to compare "theoretical" with practical.

Hi olof

As per my original post, would I be 2.9km from the exchange or 0.4km?

Thanks

1 | 2