My UBR and Ping Graph
 

Hi all,

When I go to the my UBR site, I get:

http://img507.imageshack.us/img507/829/32498343.png

And the UKInternetreport site shows:

http://img43.imageshack.us/img43/1896/60744940.png

So what is my UBR? Acto 1? Acto 12? Which?

Also, the ping graph above shows no significant disturbance for the Acto UBR's last night, yet my thinkbroadband graph says significantly different:

[img]Download Failed (1)[/img]

Any ideas why?

Thanks

Re: My UBR and Ping Graph
 

I believe the congestion point is usually your local optical node and the UBR serves umpteen of them. If that isn't correct somebody will be along to say so....

Re: My UBR and Ping Graph
 

So this street cabinet which is about 20 feet from my door, is this the local optical node?

http://img254.imageshack.us/img254/9800/photoicw.jpg

Re: My UBR and Ping Graph
 

Most probably not. You get simple distribution cabinets like that feeding a street and several cabinets are linked together going back to the optical node which converts all the signals on the coax into signals on fibre which goes back to one of the ports on the UBR. (I think).

Oh and I'd assume you are on ACTO1 although the graph says ACTO01for some reason.

I'm on NRTE25 - my hostname is cpc5-nrte25-2-0-custnnn.n-n.cable.virginmedia.com

Re: My UBR and Ping Graph
 

Interesting how the hostnames are different for some areas:

cpc11-live19-2-0-***.know.cable.virginmedia.com

Re: My UBR and Ping Graph
 

One of the two refers to the DHCP pool you're on. Can't remember which.

Re: My UBR and Ping Graph
 

when you ping the ubr externally the traffic goes over a fairly fat pipe which isnt congested, as far as I know no areas are congested at that point. However the congestion issue is your side of the ubr on a much thinner pipe.

Re: My UBR and Ping Graph
 

I posted this in answer to a similar question on the VM forum:

It works like this (but can vary in different parts of the country according to who was the original cable supplier):

1/
A small street cabinet connects either 16 or 32 customers. A larger street cabinet connects 48.

2/
The cable from a cabinet passes along to another cabinet configured as above.

3/
5 or 6 cabinets go to an optical node and it's fibre from there.

4/
In high density population areas, you might get 20 coax cabinet feeding the optical node.

5/
The optical node originally would have supported only 2 upstream channels and these might have been split between two nodes at the VM end line card. So that's a heck of a lot of users who think they're getting, say 5 meg upstream sharing just 40 meg upstream capacity.

6/
A bonding group currently has 4 downstream channels with c. 200 meg capacity to share across one or two optical nodes.

So that explains how overutilisation can occur.

The current infrastructure upgrade programme should double all the capacities I've mentioned. For high contention areas, VM should be adding more optical nodes and line cards and CMTS devices at their end to cope with the additional channels allocated. That's what they say they're doing.

So there you have it. The full explanation. I might get corrected on some piece of detail, but that's basically it.

I hope that helps you somewhat.

Re: My UBR and Ping Graph
 

Or in Ex-TW areas they can connect hundreds!

Re: My UBR and Ping Graph
 

Got a picture of one, Qasi?

Re: My UBR and Ping Graph
 

I be surprised if its only 48 seph, my cabinet serves multiple streets which amount to probably 100s of seperate properties (including houses converted to flats).

Re: My UBR and Ping Graph
 

Yeah, Chrys. You're right. I've just looked at one of my photo collection and I can see capacity for 96 with possibility of expansion to 144. That's a double door cabinet.

Re: My UBR and Ping Graph
 

interesting, can you share these pics :D

thanks for checking.

I assume with splitters that 144 can be multiplied.

Re: My UBR and Ping Graph
 

Splitters on tap points, can play havoc with attenuation or noise (if unterminated). But I've seen them in an open cabinet in a University town dahn saarf.

Anyway, here's a schematic I made from a photo of a large cabinet.

You'll note the 15 dB/18/22/29 tap points.

Re: My UBR and Ping Graph
 

Not the insides, no. But remember we have shared drops here, so they're not unusually big.

(Oddly, I just had a nap this afternoon and ended up dreaming of VM street cabs... >_<)