The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Ethernet’ Category

Fiber cables: speed and connectors

Posted by jpluimers on 2021/01/07

Similar to the CAT# designation for speed categories, fiber cables have an OM# designation. [WayBack] OM1 fiber, OM2 fiber, OM3 fiber and OM4 fiber overview explain this well, and has this quote and image tables:

There are four kinds of multimode fibers: OM1 fiber, OM2 fiber, OM3 fiber and OM4 fiber. The letters “OM” stand for optical multi-mode.

Both OM1 and OM2 work with LED based equipment that can send hundreds of modes of light down the cable, while OM3 and OM4 are optimized for laser (eg. VCSEL) based equipment.

I have combined the tables in html as:

OM1 OM2 OM3 OM4
Maximum distance for 100 Mbit/s 2000m 2000m 2000m 2000m 100BASE -FX
Maximum distance for 1 Gbit/s 275m 550m 550m 1000m 1000BASE-SX
Maximum distance for 10 Gbit/s 33m 82m 300m 550m 10GBASE-SR
Maximum distance for 40 Gbit/s not specified not specified 100m 150m 40GBASE-SR4
Maximum distance for 100 Gbit/s not specified not specified 100m 150m 100GBASE-SR10 / 100GBASE-SR4
Diameter 62.5/125µm 50/125µm 50/125µm 50/125µm
Jacket coulors (often also cable colours) Orange Orange Aqua Aqua
Optical source LED LED VCSEL VCSEL
Bandwidth 200MHz*km 500MHz*km 2000MHz*km 4700MHz*km

 

Unlike CAT cabling, fiber cables can have various connectors, of which SC and LC are the most common as explained in [WayBack] SC vs LC—What’s the difference? which has this quote and image table:

  • Size: LC is half the size of SC. Actually, one SC-adapter is exactly the same size as a duplex LC-adapter. Therefore LC is more and more common in central offices where packing density (number of connections per area) is an important cost factor
  • Handling: SC is a true “push-pull-connector” and LC is a “latched connector”, although there are very innovative, real “push-pull-LCs” available which have the same handling capabilities like SC.
  • The History of Connector: The LC is the “younger” connector of the two, SC is wider spread around the world but LC is catching up. Both connectors have the same insertion loss and return loss capabilities. Generally, it depends where in the network you want to use the connector, no matter SC or LC, even the other different kinds of connector.

In html:

Name Mating
cycles
Ferrule
size
Typical
insertion loss
(dB)
IEC
specification
Cost Ease
of
use
Application
features
SC 1000 Ø 2.5mm
ceramic
0.25-0.5 61754-4 $$ ••••• Mainstream, reliable, fast deployment, field fit
LC 500 Ø 1.25mm
ceramic
0.25-0.5 61754-20 $$ ••••◦ High density, cost effective, field fit

Related:

–jeroen

Posted in Ethernet, Network-and-equipment, Power User | Leave a Comment »

GL-AR300M – GL.iNet: nice small device allowing NAT over WAN, WiFi, 3G/4G modem, or OpenVPN

Posted by jpluimers on 2020/08/28

Still glad I got a few of [WayBack] GL-AR300M – GL.iNet: it makes travel life so much easier when you cannot use tethering.

I got the model GL-AR300M with external antennas (the GL-AR300M only has internal ones with a much shorter range).

Powered over USB, it runs OpenWRT and can NAT a local network towards an external network on the WAN, WiFi or (via USB) 3G/4G modem.

Despite doing only 2.4Ghz, it was a life saver in many occasions (there is a 5Ghz model, but it has over heating issues).

It can even run as an OpenVPN client, but given the hardware it is limited to about 10 Mhz (and gets quite warm).

Over USB, you can access web-cams, hard-disk, and more.

The internal LAN is a life saver when for instance you hook it to a stack of Raspberry Pi devices.

Docs at [WayBack] GL-AR300M – GLI Docs

I’m not the only one happy with it:

Below are some videos with config tips and reviews.

–jeroen

Read the rest of this entry »

Posted in Development, Ethernet, Hardware Development, LifeHacker, Network-and-equipment, Power User, Raspberry Pi, VPN, WiFi | Leave a Comment »

Netgear Prosafe GS110TP – Tweakers

Posted by jpluimers on 2020/04/24

Interesting Power over Ethernet (PoE) capable router: [WayBack] Netgear Prosafe GS110TP – Tweakers

About the same price as [WayBackAmazon.com: Netgear Prosafe GS110TP

–jeroen

Posted in Ethernet, Network-and-equipment, Power User | Leave a Comment »

XW6600 WOL – stopped working on Windows 10 – my trusty APC PDU to the rescue

Posted by jpluimers on 2020/01/17

A long time ago I wrote in Mac/PC: sending Wake-on-LAN (WOL) packets « The Wiert Corner – irregular stream of stuff “I’ve succesfully woken up these machines: HP XW6600 running ESXi 5.1 ThinkPad W701U running Windows 7”.

The XW6600 have now been demoted to Windows 10 machines that I only need every now and then, so most of the time they are shutdown.

However, with the installation of Windows 10 however, they stopped reacting to WOL (Wake on LAN).

Per web-search results, I’ve tried all the permutations of the below settings to no avail.

Luckily, my trusty APC PDU AP7921 (and little sister AP7920) helped out: when setting the “Reboot Duration” to 30 seconds or more (so the power fully drains), it can be rebooted.

Note that since I bought these a long time ago, they have been replaced by these:

Firmwares:

Power usage:

  • an XW66000 with 32 gigabytes of RAM and one hard disk takes between 0.6-1.2 Ampère of current, which at 230 Volt is 140-275 Watt.
  • over one day that is between 3.4 and 6.6 kWh

Settings tried

Read the rest of this entry »

Posted in Ethernet, Hardware, HP XW6600, Network-and-equipment, Power User, Wake-on-LAN (WoL), Windows, Windows 10 | Leave a Comment »

`ll header` in `martian source` is the Data Link Layer: 2 MAC addresses

Posted by jpluimers on 2019/06/03

The ll header field in a martian source message on linux is about the [WayBackEthernet frame – Wikipedia: Data Link Layer.

The first 6 hex digits are the source MAC address, the next are the destination MAC address:

May 10 08:59:24 linux kernel: IPv4: martian source 255.255.255.255 from 192.168.17.44, on dev eth1
May 10 08:59:24 linux kernel: ll header: 00000000: ff ff ff ff ff ff 00 0c 29 f7 0f fe 08 00 ........).....

In the above example:

  • Destination = MAC ff ff ff ff ff ff (broadcast, which corresponds with IPv4 target 255.255.255.255)
  • Source = MAC 00 0c 29 f7 0f fe (specific, which I could verify after checking out the machine having IPv4 192.168.17.44)
  • EtherType  08 00 (IPv4)

Some sources indicate it is a martian, as 255.255.255.255 is never a valid IP address, but [WayBack] Martian packet – Wikipedia: IPv4 disagrees.

References:

–jeroen

Posted in Ethernet, Network-and-equipment, Power User | Leave a Comment »

 
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