On Tue, 12 Jan 2010, Jeremy Chadwick wrote:
On Tue, Jan 12, 2010 at 02:50:29PM -0500, Charles Sprickman wrote:
On Tue, 12 Jan 2010, Charles Sprickman wrote:
On Jan 12, 2010, at 12:04 PM, Boris Samorodov <b...@ipt.ru> wrote:
On Tue, 12 Jan 2010 17:14:44 +0200 Marin Atanasov wrote:
I'm thinking about the following situation - 1 system acting like a host
with a serial port hub, each port of the hub is connected to a different
machine on sio0, using null modem cables.
Along with milti-io serial cards we use multi-usb serial
converters, such as SUNIX UTS7009P (7 USB to serial adapter):
http://www.sunix.com.tw/it/en/LinkCraft/UTS4009P_UTS7009P.htm
I need to look it up when I'm in front of a real computer, but
there are a number of reasonably priced multport USB to serial
converters out there.
Here we go:
http://www.usbgear.com/USB-Serial.html
Some very cool stuff there. They also list the chipset used in some
of those so you have some idea if it will work with FreeBSD. I
think Vixie originally pointed me to this model:
http://www.usbgear.com/computer_cable_details.cfm?sku=USB-16COM-RM&cats=199&catid=493%2C494%2C474%2C199%2C461%2C106%2C1009%2C601
If anyone has the lowdown on which chipsets generally work with
FreeBSD (especially with all the changes in 8.0), that would be
great.
The same device appears here:
http://www.serialgear.com/USB-16COM-RM.html
http://www.allserial.com/usb_16com-rm.html
Damn, $130 more than usbgear.com...
Quite inexpensive compared to an actual serial console server!
Very much so! And if you already have a sort of "utility box" in a rack,
this makes a nice add-on. There are some very cheap 4 and 8 port models
as well.
I had no idea such a device existed (well, USB-to-serial adapters, sure,
just not ones which housed 16 adapters or was rack-mountable. :-) ).
Who knows what's inside, there are two USB hubs in there... But yeah,
rack-mount and AC power are nice.
Decently sized FIFO buffers as well (128/384 byte Tx/Rx), at least
compared to a classic 16650A (14/16 byte Tx/Rx). Usually larger FIFO ==
can handle higher bps without character loss.
I've 5 questions about this device:
* Does it work with/use hardware flow control (CTS/RTS)?
Yes. There were a few machines that were giving me issues with the old
3-wire RocketPort card we had (which only had 8 ports, cost more *used*
than this USB thing cost new, had buggy drivers, and only had a 3-wire
interface) and they worked fine when moved to this device.
* Have you tested it for character loss at 115200bps rates?
Nope, never had much luck getting everything (BIOS, loader, getty) all
talking at the same speed, so I just leave it at 9600. Zero issues
though...
* How do you configure each port (speed, flow, etc.)?
I let conserver deal with that - I set the baud, parity and "options" in
the default stanza for all ports. It apparently does the "right thing"
when opening the port. Again, zero issues.
* Does it work under FreeBSD 8.x (given that the entire USB stack
was re-written)?
No idea, don't even have an 8.x machine at that site. If you have any
contacts over at ISC, you might ask there, I got the impression from Vixie
that this device became part of their standard co-lo build.
* Do you have any idea what the power usage is on this device (in amps)?
(Our MRV claims 1A max, but drives about 0.25A or so).
No clue, but I imagine it's negligible. The device generates almost no
heat, and all of that is in the area around the power supply.
The above model works great on an old 4.11 box. It's an FTDI
chipset - at the very bottom of the page they even claim FreeBSD and
OpenBSD support.
dmesg:
uhub2: Genesys Logic USB Hub, class 9/0, rev 1.01/0.11, addr 2
uhub2: 7 ports with 7 removable, self powered
ucom0: FTDI USB FAST SERIAL ADAPTER, rev 2.00/5.00, addr 3
[...]
ucom11: FTDI USB FAST SERIAL ADAPTER, rev 2.00/5.00, addr 8
[...]
uhub3: Genesys Logic USB Hub, class 9/0, rev 1.01/0.12, addr 9
uhub3: 4 ports with 4 removable, self powered
ucom12: FTDI USB FAST SERIAL ADAPTER, rev 2.00/5.00, addr 10
[...]
ucom15: FTDI USB FAST SERIAL ADAPTER, rev 2.00/5.00, addr 11
Very nice -- the fact they're using FTDI chips is good (from what I
understand of USB-to-serial adapters).
Yep, this was all plug-and-play. I also found a source for db9-db9 null
modem cables at about $3 a pop - much simpler than building rj-xx to db9
adapters (xyplex, rocketport) or dealing with giant harnesses (cisco,
xylogics).
We have a 16 port model that's rack mounted and cost around $400.
It works better many of the more expensive multiport serial cards.
Paired with conserver, it's a really nice solution. Conserver's
logging is great...
I've used old dedicated terminal servers in the past and they can
be a pain to deal with. The newer ones are probably nicer, but
are also lots of money.
Classic devices (like the Portmaster) are indeed a pain in the butt to
deal with. I've no experience with Ciscos, but in the case of the PM,
documentation vs. implementation mismatch galore. The MRV devices are
thoroughly documented (it borders on overwhelming -- I'd say half of the
configuration parameters are foreign to me), and I think the Cyclades TS
devices are as well; it's the cost of the Cyclades which blows my mind
(zero justification for it too, other than "enterprise cost mentality",
e.g. charge as much as possible because large businesses will pay it).
I had surplus junk from the dialup days - Xylogics Annex boxes and Xyplex
boxes. Both suck in so many ways that they aren't even worth using. The
Annex stuff is still stuck in my brain, wasting valuable space.
I think for folks who want a multiport serial console device that sits
on Ethernet, the MRV or Cyclades device would be a good choice, since
it's a standalone unit which doesn't need to be physically cabled to a
"host" box (and often a good choice for those who want modem-based OOB
access to devices, since it can house a v.90 modem). For those with
less requirements and want to spend less, the above USB-to-serial device
looks fantastic -- and at almost 1/4th the cost of our MRV. :-)
Hey, get an Alix board, slap it in a case with a CF card and put FreeBSD
and conserver on there. Plug an old Courier into one of those serial
ports and setup ppp for dial access. You'd still beat the cost of any
"appliance" and have something that's just as reliable. Conserver is what
really makes this a plug-and-play setup - it's very easy to get going and
it "just works".
As usual, thanks for the insights, Charles!
Thank Vixie and ISC, they're the ones that found this device and the
usbgear.com guys...
C
--
| Jeremy Chadwick j...@parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP: 4BD6C0CB |
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