dummies guide to understanding routers OT

[The Natural Philosopher]

So try http://192.168.254.254 then

[John Rumm]

The router may be configured to use a different port from normal. So try:

192.168.254.254:8080

Failing that, what make / model of router is it?

[John Rumm]

Those default to 192.168.1.254 normally...

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[Tim Lamb]

Yay!

It worked!

Now what?

[Tim Streater]

Perhaps its 192.168.254.254 in that case.

[Tim Watts]

On Monday 30 December 2013 18:43 Tim Streater wrote in uk.d-i-y:

nmap would be the OP's friend at this point...

[Tim Lamb]

In message , Tim Watts writes

Wassat then?

Finally stumbled to DSL connection *detail*

Bandwidth up/down .448/7.2Mb line attenuation 12,0/23,5 dB SN margin 23,0/7,5 dB FEC errors 4/605.072 CRC errors 0/1.166 HEC errors 0/125

So what does it mean?

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[Dave Liquorice]

448 kbps sync up to your ISP, normal and as fast as normal ADSL will go. 7.2 Mbps sync down from your ISP to you, perhaps a bit lower than I'd expect.

12 dB loss up stream, 23.5 dB loss down stream. How much the lenght of the line is reducing the signal. 23.5 dB ought to mean that ADSL2 syncs flat out and ADSL2+ should manage around 18 to 20 Mbps.

FEC - Forward Error Correction. The data is coded such that a limited number of errors per packet can be corrected by the reciever automagically. This saves having to ask and wait for a retransmission of a corupt packet. It increases reliabilty at the expense of speed.

CRC - Cyclic Redunancy Check. A small checksum is added to each packet. When the packet is recieved the CRC of the recieved data is checked against the supplied CRC value if they match confindence is high that the data is not corupt, if the two CRCs don't match the chances are the data is corupt and some corrective action needs to be taken.

HEC - Header Error Control. A bit like CRC but with limited abilty to correct errors without needing a retransmission.

Note that "packet" may refer to packets of data at different layers. The "packet" with the CRC added could be made up of multiple packets from a lower layer with FEC correction applied.

[Tim Watts]

On Monday 30 December 2013 20:05 Tim Lamb wrote in uk.d-i-y:

Often used to scan the open TCP and UDP ports on a given host, but can also sweep scan quickly through large IP ranges - great for finding random devices.

[Tim Lamb]

Maybe they haven't done the ADSL2+ upgrade yet? The kitz site was a bit vague on my exchange detail.

Hmm.. So if the service is ADSL2+, whinging to my ISP might do something?

er. yes. In farmer speak, as reported, does any of that indicate poor line quality?

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[tony sayer]

Why such asymmetry Dave?..

[Dave Liquorice]

Up stream uses frequencies from 26 kHz to 137 kHz, downstream 138 kHz to 1104 kHz (ish for ADSL2, IIRC ADSL2+ goes up to 2200 kHz). Simply the higher the frequency the more attenuation it suffers.

[The Natural Philosopher]

upstream uses lower frequencies.

[Dave Liquorice]

What does Sam Knows say? (Just looked at our exchnage on kitz, same info as near as damn it).

ADSL2+ is part of the "21CN WBC" BT core network changes. So the date (if any) of that is the possible ADSL2+ date.

I'd sort of expect the DSLAM and your CPE to negociate to ADSL2+ speeds but the backhaul connection to your ISP limiting that to 8 Mbps (ish). It might be worth asking your ISP as they do have to migrate customers from one backhaul system to another, my ISP does this automatically when an exchange switches but I guess not all do.

With a sync of 7.2 Mbps and only ADSL2 I'd say not. Poor extension wiring, bell wire noise injection, multiple filters etc can easily knock 1 Mbps off the sync rate. I recently tried to use a bit (5 to

10 yds) of (electrician) installed telephone cable that was CCS (copper clad steel), that knocked around 2 Mbps off my ADSL2...

[Tim Lamb]

Sam says BT Wholesale ADSL,ADSLmax, WBC (21CN) are available at my local exchange.

Ah! That might be worth following up. Demon->C&W->THUS-> Vodaphone not the easiest to contact. I'll get the home wiring tidied first.

Just offered a strong magnet to a short length of accessible cable without noticeable effect. I'll get a better idea when I fiddle with it. Electrician installed 1995.

Many thanks for your and others kind help. I think I now have enough to talk sensibly to the Demon help line.

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[Tim Streater]

I think you'd need to oscillate your arm at a few MHz for that to have an impact.

[The Natural Philosopher]

sometimes the router itself is set to only negotiate ADSL and/or simply cannot negotiate ADSL2+ ..a config change a and a reboot/resynch may solve this.

[Tim Lamb]

In message , Tim Streater writes

I was trying to detect steel cores through the insulation:-)

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[Tim Lamb]

Sudden blinding flash of hindsight! The service I signed up to was restricted to 8Meg max.

The current lowest offer (at the same price) from Demon is Business Lite with up to 19Meg. However, their line check on my phone number only reckons on 6Meg:-(

5 ish is ample for my current use but I imagine sites will get loaded with more and more junk as designers target the urban elite:-(

[tony sayer]

A slight Doh!, here re that issue;!!...