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40

This is an interesting question since I've never seen anything that authoritatively states the design decisions behind that choice. Everything that I've come across, whether on the Interwebs or from conversation with people smarter than me in this area, seem to indicate two possibilities: Future proofing Extra shielding Future Proofing By the time of the ...


39

For the same reason why the first and second pair are connected to pins 4, 5 and 3, 6: compatibility with telephone systems. In telephony main pair is the middle pair and second pair is the next one from middle (pins 2, 5 in RJ11 and 3, 6 in RJ45). If you're using Fast Ethernet or Ethernet, you can route telephone signal in regular cable and it will work ...


33

An unmanaged switch won't have the feature you're looking for and connecting two ports between both switches will create a switch loop, which will effectively render the switches and the network unusable. A managed switch should have the feature that you're looking for, which is called Link Aggregation (LAG). Before purchasing a managed switch make sure to ...


31

Sorry, I know this is resurecting an old thread, but I felt like I needed to put my 2 cents in...simply because I've gone through this recently at my new workplace and am looking into "testing" all the lines that have been run in the last 10 years. CAT5, CAT5e and CAT6 share a few common requirements. Among those things are the RJ45 connectors (clear ...


27

CATx are physical cable wiring standards, specifying physical wiring characteristics of the cable, like impedance, number of conductors, twist rate, etc. Switches do not care about the physical properties of the cable. All they care about is whether or not the cable is able to successfully transmit data. It is assumed that cabling used will be within spec ...


23

During my attempts to trace the lines using a toner and probe, I noticed that the lines that are active have a very weak tone signal. It is so weak, I can't trace it. The other lines, however, I was able to trace without any issues. Anyone know why the signal is so weak? Is it because the line is active and data packets are watering down the toner'...


19

Question is a bit broad but i believe it's still valid for this site. A good initial site survey is very important. Depending on the scale of this, you may need a professional networking company to run the survey for you. I will assume that this has a learning purpose so i'll list what we do when we go to a new site. Disclaimer: a proper network survey is ...


19

Taken from there SFF-8087 Internal four channel connector (data only) The SFF-8087 connector is a very widely used connector type that is commonly used today on SAS cards. It carries the equivalent of four SATA/ SAS 7-pin connections through a SFF-8087 to SFF-8087 cable providing 12gbps of throughput using SAS or SATA II 3.0gbps devices. ...


16

Yes, you can do this, if both switches support link aggregation (which goes by a variety of names such as bonding, NIC teaming, port trunking, etc.). You're unlikely to find this feature in consumer grade hardware or unmanaged switch. The answer to the question you referred to even specifically mentioned LACP, one common protocol for link aggregation.


15

You're limited to daisy-chain if you don't have spanning tree, as redundant links without spanning tree will cause a loop. LACP doesn't really do anything here, in your case it would only used for switch-to-switch redundancy and throughput increase. Mind that there is no point of using LACP unless switches in both ends understands the LACP protocol. My ...


14

Most (all?) current devices have implemented ethernet auto mdix. The answer is simple: You don't need such cable.


13

4-pair UTP cable with RJ-45 connectors was invented for audio telephone use. Its adoption and evolution as a medium for high-speed digital data communications has been a matter of convenience: adapting pre-existing mass-produced products for new uses rather than devising a completely new technical standard specific to one new application. The way this ...


13

I normally would associate FTP with the File Transfer Protocol :) But from: belden.com/blog F/UTP (FTP) An overall foil shield (F) with unscreened twisted pairs (UTP). This cable is very much like common UTP cables, with the addition of foil underneath the main cable jacket. Another common name for this cable is FTP. F/UTP cables are common in ...


12

These connections are rated to carry these speeds at the distance specified: | 10/100Mb | 1Gb | 10Gb | 40Gb† | 100Gb‡ Category | 100m | 37m | 100m | 55m | 100m | 50m | 100m | 15m | 100m ---------+----------+-----+------+-----+------+-----+------+-----+----- 5 | x | x | | | | | | ...


11

Normally nothing has changed between the cables between SATA I,II and III. From the official SATA-IO document: The same cables and connectors used for current SATA implementations can be used to connect SATA 6Gb/s devices. SATA-IO recommends utilizing quality components to ensure data integrity and robust operation at the fast 6Gb/s transfer rate. ...


10

Having configured a number of SmartUPSes with AP9606 in my time, I do not remember ever having had the need for an "APC-proprietary" serial cable. The documented pinout looks like a simple null-modem cable swapping the TX and RX pins: +-----------------------------------------------------------------+ | ...


10

Another quick and dirty solution is to get a partner to take a laptop and repeatedly plug and unplug into keystone of the cable you are trying to trace. While he is doing that, look at the switch(es) for the link light that keeps going on and off. If you don't have a partner, take a picture of the link lights with the laptop unplugged with your cell phone. ...


10

Gigabit requires all 4 pairs, and 10/100 only requires 2 pairs. So "testing" it with the 10/100 switches doesn't really verify that all pairs of the cable are good. For something like this, you will want to use a cable certifier, not a plain tester that just tests continuity. 30m really isn't that long of a run. If they are newer switches that support low ...


9

The open source router firmware DD-WRT appears to support link aggregation; if you're lucky enough to have bought hardware compatible with it then you could re flash the OEM firmware to DD-WRT to gain the feature. Be warned that doing so is warranty voiding; and if something goes wrong you can brick your hardware so caveat emptor. Doing this will also ...


8

I'd suggest a cabling contractor. Seriously. It helps to get some ideas of what other installations look like, and they can help guide you. In your case, you probably have HP 10642 or 10642 G2 racks. To answer your questions... Standard practice is to place your top-of-rack switches and patch panels at the rear of the cabinet. You didn't specify the ...


8

I'll take a contrarian view here. There is nearly no value in going from cat5e to cat6a in almost all office environments. 10gb copper is nasty, expensive, and flakey. It uses far more space than 5e, is heavier, and is harder to install. You have to fully test the entire cable plant including your patch cables if you want it to work. And by test I ...


8

Get a tone generator (http://www.amazon.com/Fluke-Networks-PRO3000-Tone-Probe/dp/B000FTADX0/ref=sr_1_1?ie=UTF8&qid=1383596496&sr=8-1&keywords=tone+generator) and plug that into the terminated end and use the probe to find the cables on the other end. And anytime a cable is pulled make sure the installer plans to label them cables in a manageable ...


8

Use solid core wire for structured wiring (in-wall, above ceiling, etc), it's cheaper. Use stranded core wire for everything else (eg, wall to computer, in-rack, patch panel to switch, etc) To directly address the question as stated: I remember back in the day it was a big deal to use solid cable for horizontal runs That makes no sense at all - whoever ...


8

First, keep in mind that cat5 type of cables were designed for many uses, not only for "ethernet over twisted pair", although it's the most popular application of those cables nowadays. As you can read on Wikipedia page about "Category 5 cable" in "Applications" section: Cat 5 is also used to carry other signals such as telephony and video But let's get ...


8

1) You don't need any special Ethernet cabling for direct connection since 1 GbE era, everything will auto negotiate. https://en.wikipedia.org/wiki/Medium-dependent_interface 2) Broadcom NICs you picked up are shit, you'll get a lot of issues with their performance and stability. Go Mellanox CX4LC family, it's waaaay better. 3) 10GBASE-T has higher ...


7

Don't run CAT6 cable If the bends in your cable don't exceed the minimum bend radius for the cable type then it's not an issue. If the cable lengths don't exceed the maximum cable length (in your case 100 meters/328 feet) then it's not an issue. Why run new wiring when you can simply test the existing cable (not the terminations but the cable itself) and ...


7

Regarding your additional question about number of cores... Each of the four pairs in a Cat 5 cable has differing precise number of twists per metre to minimize crosstalk between the pairs. Although cable assemblies containing 4 pairs are common, Category 5 is not limited to 4 pairs. Backbone applications involve using up to 100 pairs.[2] This use of ...


7

We have a lot of 10GE in our datacenters and we never use CAT6a for it. I would strongly recommend using SFP+. For Switch-Server connections you can use 10GE DAC cables (special copper cables with fixed SFP+ modules on both ends) that are not as expensive as optical cables/SFP+. We use these without problems to connect ESX hosts: http://www.flexoptix.net/...


7

If you've ever driven under a power line while listening to an AM radio, you probably heard the hum of the cables. At higher frequencies, signals travel in the space around the metal conductor. Theses signals bounce off the metal staples. If you have enough staples, you wind up with multiple signals reaching the receiver at different times in different ...


7

The PSE (Power Sourcing Equipment) and PD (Powered Device) negotiate to see if the end device is compatible of being powered and at what standard. So plugging in a non PoE device will not damage said device. Here is a good read about the basics of PoE (Do note though the document is quite old and was written prior to the 802.3at enhancement which modifies ...


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