cancel
Showing results for 
Search instead for 
Did you mean: 

Noise margin & attenuation

jmart
Grafter
Posts: 34
Registered: 10-09-2007

Noise margin & attenuation

According to my router my noise margin is 24dB upstream and 13dB down, while the attenuation is 8dB up and 16 dB down. Is this ok and can it cause random disconnections?
Also in 'ISP Settings' i can choose 'QoS class' but i can't find any reference to it on PN, options are CBR, UBR & VBR.
Also, at last count, I have 3 firewalls running on my connection: Windows, router & PN. How many should I run?

I've started getting random disconnects and am going through all settings I can change before taking this further, anyone any ideas?
Cheers.
9 REPLIES
N/A

Noise margin & attenuation

The snr etc is a good standard but it depends on what speed you are connecting at as these change as the speed goes up. You shouldnt have any problems with those figures. It also depends on the router most will drop the line at a snr of 6 some may go right down.
Whats is your router and speed/

The QOS isnt needed its there if you want to maintain bandwidth for certain apps see for an explanation
http://www.cell-relay.com/cell-relay/FAQ/ATM-FAQ/d/d16.html.

3 firewalls can give problems as you dont know which one is doing which turn off plus net one
jmart
Grafter
Posts: 34
Registered: 10-09-2007

Noise margin & attenuation

Actual connection speeds:
Up = 448 Kbps
Down = 7328 Kbps

Router is Philips SNA6500 (one with square power button).
I upgraded it's firmware 4 days ago but it's made no difference.
N/A

Noise margin & attenuation

The speed is great and the stats are ok. All you can do is see if the random disconnects are random or are related to something.
Make a note when it disconnects and check your line stats does your snr drop does anything happen before like heating coming on or anything that could cause a problem
jmart
Grafter
Posts: 34
Registered: 10-09-2007

Noise margin & attenuation

Thanks for the reply mwright. I've actually realised the problem wasn't as random as i thought. It was my p2p prog causing the disconnects. So after browsing many many forums i switched off my router's firewall and the problem has disappeared. I figured it must have been a prob with the router as rather than just disconnecting I would get the 'network cable has been unplugged' bubble from the system tray.
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Noise margin & attenuation

What router are you using as turning off the firewall is generally a bad thing?

Sounds like it may have been swamped with P2P sessions and went bad.

First make sure you are running the latest firmware for it as this kind of problem is often fixed with updated firmware.

Second reduce the max number of connections your P2P app is allowed to use until you find a level the router is happy with.
jmart
Grafter
Posts: 34
Registered: 10-09-2007

Noise margin & attenuation

Quote
Router is Philips SNA6500 (one with square power button).
I upgraded it's firmware 4 days ago but it's made no difference.


I was a little wary about turning off the firewall but I figured that if NAT was still enabled the router was still quite secure. Is this a correct assumption? And I do have another 2 firewalls to fall back on if needed. Until i'd had this problem i hadn't looked into port forwarding and virtual servers and stuff. I even tried a DMZ but it made no difference. My old router and, before that my BT voyager 105, could handle my p2p settings. Just one of those things I guess.
jmart
Grafter
Posts: 34
Registered: 10-09-2007

Noise margin & attenuation

P.S. Why are all posts being timestamped an hour slow?
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Noise margin & attenuation

You need to update your time zone in your profile. It doesn't update automatically.
oliverb
Grafter
Posts: 606
Registered: 02-08-2007

Noise margin & attenuation

Quote
What router are you using as turning off the firewall is generally a bad thing?

I've seen routers that test as more secure with the "firewall" turned off.

Without the firewall it creates ports as needed and unused ports are invisible.

With the firewall you have to enable ranges of ports in case they are needed and when not in use the ports still respond as closed.