I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

On 18/03/2013 19:17, brass monkey wrote:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.


I was just wondering about that, thanks.



--
Dave - The Medway Handyman www.medwayhandyman.co.uk

On 18/03/2013 19:17, brass monkey wrote:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.


For many purposes, gigabit is in the category of things that are, quite
simply, fast enough. And you often wouldn't appreciate any further speed
up. Pretty much where we are in terms of processors which hang around
most of their lives waiting for something to do!

Obviously, people can come up with things that would benefit from more
of any performance factor, but I don't think many domestic installations
need more speed sufficiently that they'd actually pay for it.

--
Rod

In message , at 19:27:27 on Mon, 18
Mar 2013, polygonum remarked:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

For many purposes, gigabit is in the category of things that are, quite
simply, fast enough. And you often wouldn't appreciate any further
speed up. Pretty much where we are in terms of processors which hang
around most of their lives waiting for something to do!

Obviously, people can come up with things that would benefit from more
of any performance factor, but I don't think many domestic
installations need more speed sufficiently that they'd actually pay for
it.

Pretty much agree. 300MB file *to* a NAS is about a minute, *from* it
twice as fast. Although I bought an awful NAS last year (didn't believe
the reviews) which really does take several days to absorb 500GB.

I'm on my second generation GB hub now, the first one from about five
years ago took so much power it almost glowed in the dark. The new one
takes a tenth of the power, and also has 8 ports instead of 4. Decent
tower PCs of that vintage have GB on the motherboard.

Anyone want a glowing 4-port hub. Cheap? I thought not.
--
Roland Perry

On 18/03/2013 20:08, Roland Perry wrote:
In message , at 19:27:27 on Mon, 18
Mar 2013, polygonum remarked:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to
NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the
100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I
spose the
drive write speed will make it similar. How the devil do they get
gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd
kill it
dead.

For many purposes, gigabit is in the category of things that are,
quite simply, fast enough. And you often wouldn't appreciate any
further speed up. Pretty much where we are in terms of processors
which hang around most of their lives waiting for something to do!

Obviously, people can come up with things that would benefit from more
of any performance factor, but I don't think many domestic
installations need more speed sufficiently that they'd actually pay
for it.

Pretty much agree. 300MB file *to* a NAS is about a minute, *from* it
twice as fast. Although I bought an awful NAS last year (didn't believe
the reviews) which really does take several days to absorb 500GB.

I'm on my second generation GB hub now, the first one from about five
years ago took so much power it almost glowed in the dark. The new one
takes a tenth of the power, and also has 8 ports instead of 4. Decent
tower PCs of that vintage have GB on the motherboard.

Anyone want a glowing 4-port hub. Cheap? I thought not.

Got gigabit around six years ago - almost by accident. Needed new router
and it happened to come with gigabit. Then got machines that could use
it. :-)

--
Rod

Roland Perry wrote:
In message , at 19:27:27 on Mon, 18 Mar
2013, polygonum remarked:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

For many purposes, gigabit is in the category of things that are, quite
simply, fast enough. And you often wouldn't appreciate any further
speed up. Pretty much where we are in terms of processors which hang
around most of their lives waiting for something to do!

Obviously, people can come up with things that would benefit from more
of any performance factor, but I don't think many domestic
installations need more speed sufficiently that they'd actually pay for it.

Pretty much agree. 300MB file *to* a NAS is about a minute, *from* it
twice as fast. Although I bought an awful NAS last year (didn't believe
the reviews) which really does take several days to absorb 500GB.

Are you quoting the transfer times for the "awful NAS"? I did a double take
at your time of one minute for 300MB and tried it myself.

For a 366MB file I get:

6.0s [61MB/s] to a QNAP NAS (SATA RAID 5)
7.7s [47.5MB/s] to a FireWire 800 drive (SATA)
9.8s [37.5MB/s] to a homebrew NAS (IDE)

Source drive in all cases a SATA I 7200 rpm drive. This may be limiting the
transfer rate because the Blackmagic disk speed test gives 123, 62 and 110
MB/s respectively. Yes that is the correct order ,tested with a 1GB test
file.

The homebrew NAS was running a backup job at the time which may explain why
it was slower.

The figure you are quoting, 5MB/s is more typical of a transfer over
100MB/s Ethernet.

--
€¢DarWin|
_/ _/

In message

, at 02:03:33 on Tue, 19 Mar 2013, Steve Firth
remarked:

300MB file *to* a NAS is about a minute, *from* it
twice as fast. Although I bought an awful NAS last year (didn't believe
the reviews) which really does take several days to absorb 500GB.

Are you quoting the transfer times for the "awful NAS"? I did a double take
at your time of one minute for 300MB and tried it myself.

For a 366MB file I get:

6.0s [61MB/s] to a QNAP NAS (SATA RAID 5)
7.7s [47.5MB/s] to a FireWire 800 drive (SATA)
9.8s [37.5MB/s] to a homebrew NAS (IDE)

No, that was the "good NAS", but it's not a high performance one.

Trying again this morning, on a PC with Win7 (so it has a Bytes-per-sec
meter) I got 15.3 MBytes/sec up and 29.1 MBytes/sec down. (20sec and 10
sec for a 300MB file). That's 125 Mbits per sec and 250 Mbits per
second.

The "awful NAS" manages about 4MBytes/sec, which is 14GB/hr, or 35 hours
to fill the entire 500GB. I suppose how many days that is depends on
whether you count 8hrs/day or 24.
--
Roland Perry

On 18/03/2013 19:27, polygonum wrote:
On 18/03/2013 19:17, brass monkey wrote:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2
via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the
100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I
spose the
drive write speed will make it similar. How the devil do they get
gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd
kill it
dead.


For many purposes, gigabit is in the category of things that are, quite
simply, fast enough. And you often wouldn't appreciate any further speed
up. Pretty much where we are in terms of processors which hang around
most of their lives waiting for something to do!

Obviously, people can come up with things that would benefit from more
of any performance factor, but I don't think many domestic installations
need more speed sufficiently that they'd actually pay for it.


Hard drives already max out gigabit connections. In fact I think SSDs
are already well passed the Sata1 3Gb/s mark.

If you want to copy large files from one computer to another it is nice
to have it happen as quickly as possible. Given the size of HD video
files I think it would be nice to have a quicker network connection.

I don't care if hardware spends most of its time hanging around doing
nothing, when I want something done I prefer it to be done fast.

On Mon, 18 Mar 2013 19:17:18 +0000, brass monkey wrote:

I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2
via a pc (windows drag and drop), the pc is peaking at ~300Mbps. On the
100meg LAN it managed ~60Mbps. I ought to try FXP between the NAS's
though I spose the drive write speed will make it similar. How the devil
do they get gigabit to work? What kind of signal level do we get, a few
milli-volts? I remember donkeys years back, if you hung a scope probe
onto a 1meg line it'd kill it dead.

Good, isn't it? Mine have been in a few eeks now and it's saved a lot of
time...



--
Use the BIG mirror service in the UK: http://www.mirrorservice.org
My posts (including this one) are my copyright and if @diy_forums on
Twitter wish to tweet them they can pay me £30 a post
*lightning surge protection* - a w_tom conductor

"Bob Eager" wrote in message
...
On Mon, 18 Mar 2013 19:17:18 +0000, brass monkey wrote:

I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2
via a pc (windows drag and drop), the pc is peaking at ~300Mbps. On the
100meg LAN it managed ~60Mbps. I ought to try FXP between the NAS's
though I spose the drive write speed will make it similar. How the devil
do they get gigabit to work? What kind of signal level do we get, a few
milli-volts? I remember donkeys years back, if you hung a scope probe
onto a 1meg line it'd kill it dead.

Good, isn't it? Mine have been in a few eeks now and it's saved a lot of
time...

It's the slew rate that's bugging me. How the hell can you get a decent
sized signal at that speed?
The slew rate must be off the scale or there's something (multitudes) that I
don't know. We're talking nanoseconds here.
A gigabit = 1 ns, yea? That puts RTL, TTL & CMOS out of the picture,
shirley?
******** to it, i'll collect my pension as normal this week
My claim to fame - I remember 75 baud or was it 110? teletype 33's

On Mar 19, 1:45*am, "brass monkey" wrote:

It's the slew rate that's bugging me. How the hell can you get a decent
sized signal at that speed?
The slew rate must be off the scale or there's something (multitudes) that I
don't know. We're talking nanoseconds here.
A gigabit = 1 ns, yea? That puts RTL, TTL & CMOS out of the picture,
shirley?

It doesn't need to go that fast. As Andrew Gabriel explained earlier,
the transitions only take place at 125MHz. What gives it the extra
speed is using all four pairs in both directions at once combined with
having multiple voltage levels. There is equalisation in the
transceivers to help compensate for frequency dependent cable losses
and to cancel the echo of locally transmitted data at each end.

Thinking about the cable being "voltage" or "current" driven isn't
really helpful. It is more useful to think of it as a set of balanced
transmission lines carrying radio signals. The cable is driven from a
balanced 100 Ohm (approximately) source impedance and it is terminated
with 100 Ohms to avoid reflections.

John

On 19/03/13 01:45, brass monkey wrote:
"Bob Eager" wrote in message
...
On Mon, 18 Mar 2013 19:17:18 +0000, brass monkey wrote:

I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2
via a pc (windows drag and drop), the pc is peaking at ~300Mbps. On the
100meg LAN it managed ~60Mbps. I ought to try FXP between the NAS's
though I spose the drive write speed will make it similar. How the devil
do they get gigabit to work? What kind of signal level do we get, a few
milli-volts? I remember donkeys years back, if you hung a scope probe
onto a 1meg line it'd kill it dead.

Good, isn't it? Mine have been in a few eeks now and it's saved a lot of
time...

It's the slew rate that's bugging me. How the hell can you get a decent
sized signal at that speed?
The slew rate must be off the scale or there's something (multitudes) that I
don't know. We're talking nanoseconds here.

there is something you don't know. Trellis code modulation. That
squeezes te last drop out of a transmission channel

Data rate of a line is the bandwidth of the wire pair times the signal
to noise ratio times the number of cables.

in gigabyte you have 4 pairs each capable of at least 100MHz and with
(over a short distance) at least 60dB S/N.

I think they encode at 5 levels in that 60dB range so that's a top rate
of 5 x 100M x 4 = 2 GIGABITS a second total. 1 GIG up one GIG down..


A gigabit = 1 ns, yea? That puts RTL, TTL & CMOS out of the picture,
shirley?

Nope. what's on the wires is analogue. By the time its digital its 32 or
64 bits wide. divide a gig by 32 and its only 34MHZ clock rate sort of
speeds.

If you like the secret of throughput is to do a lot in parallel

And use every corner of spectrum


******** to it, i'll collect my pension as normal this week
My claim to fame - I remember 75 baud or was it 110? teletype 33's


indeed. current loop telex machines. ahah



--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On 19/03/2013 09:27, The Natural Philosopher wrote:


there is something you don't know. Trellis code modulation. That
squeezes te last drop out of a transmission channel


Was that developed in North Wales?

--
Rod

On Mar 19, 9:27*am, The Natural Philosopher
wrote:
On 19/03/13 01:45, brass monkey wrote:









"Bob Eager" wrote in message
...
On Mon, 18 Mar 2013 19:17:18 +0000, brass monkey wrote:

I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2
via a pc (windows drag and drop), the pc is peaking at ~300Mbps. On the
100meg LAN it managed ~60Mbps. I ought to try FXP between the NAS's
though I spose the drive write speed will make it similar. How the devil
do they get gigabit to work? What kind of signal level do we get, a few
milli-volts? I remember donkeys years back, if you hung a scope probe
onto a 1meg line it'd kill it dead.

Good, isn't it? Mine have been in a few eeks now and it's saved a lot of
time...

It's the slew rate that's bugging me. How the hell can you get a decent
sized signal at that speed?
The slew rate must be off the scale or there's something (multitudes) that I
don't know. We're talking nanoseconds here.

there is something you don't know. Trellis code modulation. That
squeezes te last drop out of a transmission channel

Data rate of a line is the bandwidth of the wire pair times the signal
to noise ratio times the number of cables.

in gigabyte you have 4 pairs each capable of at least 100MHz and with
(over a short distance) at least 60dB S/N.

I think they encode at 5 levels in that 60dB range so that's a top rate
of 5 x 100M x 4 = 2 GIGABITS a second total. 1 GIG up one GIG down..

A gigabit = 1 ns, yea? That puts RTL, TTL & CMOS out of the picture,
shirley?

Nope. what's on the wires is analogue. By the time its digital its 32 or
64 bits wide. divide a gig by 32 and its only 34MHZ clock rate sort of
speeds.

The digital interface is generally 4 or 8 bits at 125MHz between the
MAC and the PHY. The 4 bit interface using both edges of the clock.

MBQ

On Tuesday 19 March 2013 01:45 brass monkey wrote in uk.d-i-y:


"Bob Eager" wrote in message
...
On Mon, 18 Mar 2013 19:17:18 +0000, brass monkey wrote:

I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2
via a pc (windows drag and drop), the pc is peaking at ~300Mbps. On the
100meg LAN it managed ~60Mbps. I ought to try FXP between the NAS's
though I spose the drive write speed will make it similar. How the devil
do they get gigabit to work? What kind of signal level do we get, a few
milli-volts? I remember donkeys years back, if you hung a scope probe
onto a 1meg line it'd kill it dead.

Good, isn't it? Mine have been in a few eeks now and it's saved a lot of
time...

It's the slew rate that's bugging me. How the hell can you get a decent
sized signal at that speed?

Try 10gig over copper. It exists and I have been told that the signal is
rather less than the noise - there is much cleverness involved...

--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage

Reading this on the web? See:
http://wiki.diyfaq.org.uk/index.php?title=Usenet

Tim Watts wrote:
On Tuesday 19 March 2013 01:45 brass monkey wrote in uk.d-i-y:


"Bob Eager" wrote in message
...
On Mon, 18 Mar 2013 19:17:18 +0000, brass monkey wrote:

I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2
via a pc (windows drag and drop), the pc is peaking at ~300Mbps. On the
100meg LAN it managed ~60Mbps. I ought to try FXP between the NAS's
though I spose the drive write speed will make it similar. How the devil
do they get gigabit to work? What kind of signal level do we get, a few
milli-volts? I remember donkeys years back, if you hung a scope probe
onto a 1meg line it'd kill it dead.

Good, isn't it? Mine have been in a few eeks now and it's saved a lot of
time...

It's the slew rate that's bugging me. How the hell can you get a decent
sized signal at that speed?

Try 10gig over copper. It exists and I have been told that the signal is
rather less than the noise - there is much cleverness involved...

Yeah and the maximum range spans 1 metre to 15 metres depending on the
interconnect chosen. With an amusing price range of £500 to £1500 for a
PCI card.

--
€¢DarWin|
_/ _/

On Tue, 19 Mar 2013 09:30:28 +0000, Tim Watts wrote:
Try 10gig over copper. It exists and I have been told that the signal is
rather less than the noise - there is much cleverness involved...

I can get a few times that over wood, by carrying a 1TB drive across the
room... ;-)

On Tue, 19 Mar 2013 21:41:56 +0000 (UTC), Jules Richardson wrote:

Try 10gig over copper. It exists and I have been told that the signal
is rather less than the noise - there is much cleverness involved...

I can get a few times that over wood, by carrying a 1TB drive across
the room... ;-)

If shifting lots of data any distance, never under estimate the bandwidth
of the postal service...

--
Cheers
Dave.

Jules Richardson :
On Tue, 19 Mar 2013 09:30:28 +0000, Tim Watts wrote:
Try 10gig over copper. It exists and I have been told that the signal is
rather less than the noise - there is much cleverness involved...

I can get a few times that over wood, by carrying a 1TB drive across the
room... ;-)

I've not heard the term for a few decades, but that used to be called
"Sneakernet".

--
Mike Barnes

On 19/03/2013 21:41, Jules Richardson wrote:
I can get a few times that over wood, by carrying a 1TB drive across the
room...;-)

"Never underestimate the bandwidth of a station wagon full of tapes"

Andy

In article om,
"brass monkey" writes:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps.

Gigabit is a good match to the real throughput you're likely to get
from a 7200 RPM disk. I can get just about gigabit throughput backing
up between my systems with 7200 RPM disks (although I had to do some
tuning of buffering to get there).

I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts?

IIRC, it's the order of a volt.
It works by sending the data over all four pairs in both directions
at the same time. The actual baud rate on any one pair is the same as
100Mbit ethernet (which was already at the 125Mbaud limit of Cat5e
cable), but the use of all 4 pairs and additional voltage levels to
encode more bits/baud enables it to achieve 10 times the throughput.

I remember donkeys years back, if you hung a scope probe onto a 1meg
line it'd kill it dead.

I recall putting a scope on a 10Mbit coax ethernet. If you triggered on
the start of a frame, and did an ftp file transfer, you could see things
like the high order TCP sequence number bits counting up in binary (if
you're used to watching an incrementing binary bit pattern). One thing
that surprised me was how stunningly different the signal amplitudes were
from different systems on the ethernet - if there were only a few active
systems, you could use this to identify them.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

brass monkey :
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

I can't answer your questions but I was also Dead Impressed when I first
gave the gigabit switch some real work to do. I immediately laid plans
to rewire the parts of the network that were sharing LAN and phone on
the same CAT5 cable.

It's not often that the new technology works ten times as fast as the
old one.

--
Mike Barnes

On Mon, 18 Mar 2013 20:36:30 +0000, Mike Barnes
wrote:

brass monkey :
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

I can't answer your questions but I was also Dead Impressed when I first
gave the gigabit switch some real work to do. I immediately laid plans
to rewire the parts of the network that were sharing LAN and phone on
the same CAT5 cable.

It's not often that the new technology works ten times as fast as the
old one.

10mb/s 100mb/s
They made a big thing about "fast" ethernet being backward compatable:
"10/100Mb/s" but they don't do that with Gigabit, even though it will
fall back to 100Mb/s and I think 10Mb/s too.

--
Graham.

%Profound_observation%

In article ,
Graham. writes:
On Mon, 18 Mar 2013 20:36:30 +0000, Mike Barnes
wrote:

brass monkey :
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

I can't answer your questions but I was also Dead Impressed when I first
gave the gigabit switch some real work to do. I immediately laid plans
to rewire the parts of the network that were sharing LAN and phone on
the same CAT5 cable.

It's not often that the new technology works ten times as fast as the
old one.

10mb/s 100mb/s
They made a big thing about "fast" ethernet being backward compatable:
"10/100Mb/s" but they don't do that with Gigabit, even though it will
fall back to 100Mb/s and I think 10Mb/s too.

There were some holes in the spec which didn't cope with having
just a 2-pair cable when doing gigagbit negotiation, although I
think all chipsets now spot that failure and renegotiate at
100Mbit max when it happens.

Again, some early 10GBASE-T interfaces were 10G-only, and couldn't
negotiate down.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Tue, 19 Mar 2013 01:18:12 +0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
Graham. writes:
On Mon, 18 Mar 2013 20:36:30 +0000, Mike Barnes
wrote:

brass monkey :
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

I can't answer your questions but I was also Dead Impressed when I first
gave the gigabit switch some real work to do. I immediately laid plans
to rewire the parts of the network that were sharing LAN and phone on
the same CAT5 cable.

It's not often that the new technology works ten times as fast as the
old one.

10mb/s 100mb/s
They made a big thing about "fast" ethernet being backward compatable:
"10/100Mb/s" but they don't do that with Gigabit, even though it will
fall back to 100Mb/s and I think 10Mb/s too.

There were some holes in the spec which didn't cope with having
just a 2-pair cable when doing gigagbit negotiation, although I
think all chipsets now spot that failure and renegotiate at
100Mbit max when it happens.

Again, some early 10GBASE-T interfaces were 10G-only, and couldn't
negotiate down.

The cable to my lad's room only has the 1-2 & 3-6 pairs connected when
plugged in to the gigabit switch a PC is fine at 100Mb but the NIC in
his I-MAC will not negotiate a connection unless I plug it into one of
the router's 10/100 ports.

I have also seen an odd thing at a couple of sites at work.

Existing PC on what should be a Gigabit LAN only working at 100
New PC indicates it is connected at 10Mb/s but there is no meaningful
connection in practice. Network tester indicates no dc fault on all 6
pairs and a visual check at both sockets show their are no split
pairs. Length of cable, about 15 meters.

There is unlikely to have been any joints along the way although I
could not absolutely confirm that.

As I was not ultimately reasonable for the cabling I escalated the
fault to someone who was, but it was difficult to explain why the old
equipment worked reasonably well but the new stuff wouldn't work at
all.

--
Graham.

%Profound_observation%

On 18/03/2013 19:17, brass monkey wrote:

I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

Yup for bulk transfers it makes a big difference...

I was at a clients other other week migrating someone to a new PC, IO
noted he had 12GB in his email folder, and had the sinking "I am going
to be here a while" feeling. Then I remembered I had replaced their
switch with a gigabit one a few years back. Brought the whole thing down
to under 30 mins ;-)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 2013-03-18, John Rumm wrote:

On 18/03/2013 19:17, brass monkey wrote:

I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

Yup for bulk transfers it makes a big difference...

I was at a clients other other week migrating someone to a new PC, IO
noted he had 12GB in his email folder, and had the sinking "I am going
to be here a while" feeling. Then I remembered I had replaced their
switch with a gigabit one a few years back. Brought the whole thing down
to under 30 mins ;-)

How does that compare with sticking the old computer's HDD in a USB
enclosure, plugging it into the new one, & copying from there? (This
assumes, of course, that the old one is being decommissioned.)

On 18/03/2013 21:38, Adam Funk wrote:
On 2013-03-18, John Rumm wrote:

On 18/03/2013 19:17, brass monkey wrote:

I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.

Yup for bulk transfers it makes a big difference...

I was at a clients other other week migrating someone to a new PC, IO
noted he had 12GB in his email folder, and had the sinking "I am going
to be here a while" feeling. Then I remembered I had replaced their
switch with a gigabit one a few years back. Brought the whole thing down
to under 30 mins ;-)

How does that compare with sticking the old computer's HDD in a USB
enclosure, plugging it into the new one, & copying from there? (This
assumes, of course, that the old one is being decommissioned.)

Its comparable - with gig ethernet you can cope with the full rate of
most normal hard drives. (having said that I usually take my USB to
SATA/IDE interface to such jobs anyway since its often easier to just
hook the drive up directly.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 18/03/2013 19:17, brass monkey wrote:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.



Ethernet is a balanced line current interface, it doesn't need much volts.

It avoids most of the interference by being a twisted pair as the noise
gets on both and doesn't get any further.

Its also isolated by virtue of a transformer at each end of each pair
unless you are using PoE.

In article om,
"dennis@home" writes:
Ethernet is a balanced line current interface, it doesn't need much volts.

It avoids most of the interference by being a twisted pair as the noise
gets on both and doesn't get any further.

Its also isolated by virtue of a transformer at each end of each pair
unless you are using PoE.

Still has to be isolated even with PoE, except for a special case of
a terminal device which is in an insulated plastic case with no connections
other than the single ethernet RJ45 itself (such as a wireless access point
with no external aerial connection).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Is it not all to do with it being current driven at a low impedence?

Brian

--
From the Sofa of Brian Gaff Reply address is active
"brass monkey" wrote in message
eb.com...
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via
a pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg
LAN it managed ~60Mbps. I ought to try FXP between the NAS's though I spose
the drive write speed will make it similar. How the devil do they get
gigabit to work? What kind of signal level do we get, a few milli-volts? I
remember donkeys years back, if you hung a scope probe onto a 1meg line
it'd kill it dead.

On 18/03/2013 19:17, brass monkey wrote:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I spose the
drive write speed will make it similar. How the devil do they get gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd kill it
dead.


....and a faster version is already available, albeit expensively:
http://en.wikipedia.org/wiki/10_Gigabit_Ethernet

On 18/03/2013 22:41, Titus Aduxass wrote:
On 18/03/2013 19:17, brass monkey wrote:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2
via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the
100meg LAN
it managed ~60Mbps. I ought to try FXP between the NAS's though I
spose the
drive write speed will make it similar. How the devil do they get
gigabit to
work? What kind of signal level do we get, a few milli-volts? I remember
donkeys years back, if you hung a scope probe onto a 1meg line it'd
kill it
dead.


....and a faster version is already available, albeit expensively:
http://en.wikipedia.org/wiki/10_Gigabit_Ethernet

Huh! Old hat. Slow.

http://en.wikipedia.org/wiki/100_Gigabit_Ethernet

--
Rod

"brass monkey" wrote:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2 via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg LAN
it managed ~60Mbps.

Do you mean Mbps or MBps?

Your figures look wrong in either unit. Gigabit Ethernet is capable of
600-800 Mbps sustained transfer speeds. So your figure looks about half of
what one would expect or if you mean MBps that would be almost three times
the expected transfer rate. OTOH presumably you are talking SMB on the NAS
and Windows copy is hardly efficient either. But it seems wrong to only be
getting half the practical transfer rate.

--
€¢DarWin|
_/ _/

"Steve Firth" wrote in message
...
"brass monkey" wrote:
I just bunged a gigabit switch on my LAN. Blimey, copying NAS1 to NAS2
via a
pc (windows drag and drop), the pc is peaking at ~300Mbps. On the 100meg
LAN
it managed ~60Mbps.

Do you mean Mbps or MBps?

Your figures look wrong in either unit. Gigabit Ethernet is capable of
600-800 Mbps sustained transfer speeds. So your figure looks about half of
what one would expect or if you mean MBps that would be almost three times
the expected transfer rate. OTOH presumably you are talking SMB on the NAS
and Windows copy is hardly efficient either. But it seems wrong to only be
getting half the practical transfer rate.

Well, its taken ~17hrs to shift 800gigabytes. The peak I saw was
~300megabits/sec so NAS to pc to NAS is about right for 17hrs. I was just
trying FXP but have to go out