[187490] in North American Network Operators' Group
Re: Devices with only USB console port - Need a Console Server
daemon@ATHENA.MIT.EDU (Jared Mauch)
Tue Feb 2 16:12:20 2016
X-Original-To: nanog@nanog.org
From: Jared Mauch <jared@puck.nether.net>
In-Reply-To: <CAP-guGX=CZ9uV28nWAUuNcyX1ZMDkwHPNDdjnh37oVRstJ-9YA@mail.gmail.com>
Date: Tue, 2 Feb 2016 16:12:16 -0500
To: William Herrin <bill@herrin.us>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
> On Feb 2, 2016, at 3:56 PM, William Herrin <bill@herrin.us> wrote:
>=20
> On Tue, Feb 2, 2016 at 9:11 AM, Jared Mauch <jared@puck.nether.net> =
wrote:
>> Yes, but I'm always concerned about what boot messages are =
lost
>> or things you can't quite do properly (like send break, etc) to get =
into
>> the device as you're waiting for the USB to initalize, driver to =
present
>> to OS, etc.. Maybe they spent more time thinking about this than I
>> am aware, but it's something I've not had a proper solution explained =
to me
>> for.
>=20
> Hi Jared,
>=20
> Like all USB to serial adapters, the the USB port on the router is
> powered by the laptop or whatever device it's plugged in to. It
> initializes and is ready before you turn the router on.
>=20
> I have not had any problems sending a serial break via USB-to-serial
> adapters. Have you?
Yes.
I=E2=80=99ve had a lot of issues with various USB serial devices and =
proper
support. There=E2=80=99s a lot of cheap windows only hardware out =
there.
> You can get a server in a shallow-depth 1U case with a solid state
> drive just as readily as a serial console server. Add USB ports and
> hubs. This gives you a Linux box on site (handy for troubleshooting)
> and might simplify your cabling (put USB hubs beside a bank of devices
> and run only one cable back to the server). A little bit of scripting
> with the hotplug system will let you associate the USB device using a
> given serial number with whatever name you care to give it, which
> might also simplify documentation for which router is plugged in
> where.
If you look at a modern router, eg: ASR9922, you have at least 4 serial
ports that need to be connected. Adding a server per router gets
expensive quickly, not to include keeping the right kvm/vmware -> vm
mapping in place for the work.
> As for why they made the change... EIA-232 serial ports are becoming
> rare. Not much uses them any more and it has become hard to find a
> laptop with one built in.
Like I said, that=E2=80=99s why we=E2=80=99ve seen things like that CERN =
open hardware solution
come into play. It=E2=80=99s cheaper than your above mentioned server =
and has more
robust support for the =E2=80=9Cindustry standard=E2=80=9D RJ45 pinout.
- Jared=
