Part 5…of the same thing

 photo duplex mismatch_zps33wlqhnk.png

I’m suspicious of this question for a few reasons but lets, attempt, to get into some of these potential answers. However, I have a strong feeling that there is obvious clear answers pointing to prove that any of this is true and that this isn’t an arbitrary question. At least that’s my suspicion based on past history.

Ok so lets do this, this is too much writing for list so lets go with paragraph form.

Incorrect VLAN, I don’t necessarily understand VLANs but I kind of understand its a form of subnetting but the exact differences in practice kind of elude me. However with virtualization, I understand it. So from a website I found this Another consideration to keep in mind is that membership to a VLAN can be assigned both statically and dynamically. In static VLAN assignment, the switch ports are assigned to a specific VLAN, and new systems added will be assigned to the VLAN associated with that particular port. For example, plug a new system into port 8 and the user becomes part of the administrator’s network. Make sure you have the right port assigned to users. Which doesn’t really sound like it would cause a speed issue. Why would have you have a ‘slow’ VLAN?

Speed/duplex mismatch between the PC and the computer. They say this is the answer but I’m highly suspect. So from the web: A duplex mismatch occurs when two devices connected by Ethernet do not properly negotiate their connection. Ethernet has the option of running at different speeds (10, 100, or 1 Gbps) and has the option of running half duplex or full duplex. Choosing a mode of operation occurs when the cable is first connected or when an endpoint is first powered up. It is determined by a protocol negotiation between the two endpoints, which in theory should find the highest speed, and should choose full duplex if it is available and half duplex if full duplex is not available. In some cases that negotiation fails, and one end decides to run full duplex while the other end decides to run half duplex. Because the two endpoints are not running a common protocol, packet loss occurs. Honestly this seems highly unlikely on a windows PC in 2019 but ok. That’s what they are saying the issue is. So how the hell do we fix this? Again, this seems a bit far fetched as most of the answer pages are from 2009 and back Adjust duplex. That’s a fairly deep solution and it only drops it to half. I feel that this is more of a slightly obscure legacy issue than a modern problem that I would see in the field. This is kind of my gripe with actually doing the work and spending the money on CompTia exams but here I am, making the commitment to actually passing these things.

This one, I suppose, would cause latency issues. I read a little bit about this, mostly on Cisco sites, and it looks like this could cause issues with latency.

Bandwidth of the uplink ports on the switch are saturated. I’m not really sure what uplink ports are so I guess that’s a good place to start An uplink port is a special port (i.e., connector) on a network switch or hub that reverses the transmit and receive circuits of any twisted pair cable connected to it. It is also referred to as an MDI (medium dependent interface) port. Uplink ports eliminate the need for crossover cables Other than that, I don’t quickly see any info about what happens if they get saturated. It would be hard for me to imagine this being a huge issue between two switching aggregating traffic without there being another issue causing the saturation.

Given the answers, none of them really make sense, however the legacy tech problem

 photo copper and fiber_zpsi6gtgiio.png

This is for sure a list question, I have no idea what these answers are to be honest. Since I’m being honest, I’m also aware that I’m here to learn.

  • MT-RJ – MT-RJ stands for Mechanical Transfer Registered Jack. MT-RJ is a fiber-optic Cable Connector that is very popular for small form factor
  • Patch panel – While a patch panel and switch may look the same on the front with their rows of ports that is where their similarities end, as each component serves a different purpose in a telecommunications room. … A switch is required in a local area network (LAN) whether a patch panel is used or not (i still dont really know the difference)
  • 110 block – this is twisted pair wiring that again, seems legacy but I could be wrong on that. I mean, if i see a switch room with cat5 ill be lucky
  • F-connector – this is for coax but apparently can be used for fiber per this question but this isn’t obvious on a google search
 photo wifi tech_zpsbcrp18o8.png

These wifi broadcast types (not sure if im using the right term) and and auth methods get confusing. Reasonably so as servicing wifi could be an entire occupation in its self very easily. So lets make some lists about auth types and network types.

  • 802.11g – The 802.11g standard uses the same OFDM technology introduced with 802.11a. Like 802.11a, it supports a maximum theoretical rate of 54 Mbps. But like 802.11b, it operates in the crowded 2.4 GHz (and thus is subject to the same interference issues as 802.11b). 802.11g is backward compatible with 802.11b devices: an 802.11b device can connect to an 802.11g access point (but at 802.11b speeds).
  • 802.11n – With the 802.11n standard, Wi-Fi became even faster and more reliable. It supports a maximum theoretical transfer rate of 300 Mbps (and can reach up to 450 Mbps when using three antennae). 802.11n uses MIMO (Multiple Input Multiple Output) where multiple transmitters/receivers operate simultaneously at one or both ends of the link. This provides a significant increase in data without needing a higher bandwidth or transmit power. 802.11n operates in both the 2.4 GHz and 5 GHz bands.
  • 802.11ac – 802.11ac supercharges Wi-Fi, with speeds ranging from 433 Mbps all the way up to several Gigabits per second. To achieve this kind of performance, 802.11ac works exclusively in the 5 GHz band, supports up to eight spatial streams (compared with 802.11n’s four streams), doubles the channel width up to 80 MHz, and uses a technology called beamforming. With beamforming, the antennae basically transmit the radio signals so they’re directed at a specific device.
  • WPA – A WPA key is a password that you use to connect to a wireless network.
  • WPA2 – Pre-Shared Key, and also called WPA or WPA2 Personal, it is a method of securing your network using WPA2 with the use of the optional Pre-Shared Key (PSK) authentication, which was designed for home users without an enterprise authentication server.
  • WPA2 mixed mode – In a “WPA2” only network, all clients must support WPA2(AES) to be able to authenticate. In a “WPA2/WPA mixed mode” network, one can connect with both WPA(TKIP) and WPA2(AES) clients. Note that TKIP is not as secure as AES, and therefore WPA2/AES should be used exclusively, if possible.
  • WPA with TKIP (WPA-TKIP) – This is the default choice for old routers that did not yet support WPA2.
  • WPA with AES (WPA-AES) – AES was first introduced before the WPA2 standard was completed, although very few clients ever supported this mode.
  • WPA2 with AES (WPA2-AES) – This is the default choice for newer routers and the recommended option for networks where all clients support AES.
  • WPA2 with AES and TKIP (WPA2-AES/TKIP) – Routers need to enable both modes if any of their clients do not support AES. All WPA2 capable clients support AES but most WPA clients do not.

Lots of information pirated from websites. Clearly the legacy note is the winning factor in the answer. The router speed seems a bit arbitrary though.

 photo SFP_zpszpm28isz.png

So this says the environmental factors are wrong so we really only need to know two things.

  • SFP – Definition of: SFP. SFP. (Small Form-factor Pluggable) A small transceiver that plugs into the SFP port of a network switch and connects to Fibre Channel and Gigabit Ethernet (GbE) optical fiber cables at the other end. Superseding the GBIC transceiver, SFP modules are also called “mini-GBIC” due to their smaller size.
  • OM1 – OM1 cable typically comes with an orange jacket and has a core size of 62.5 micrometers (µm). It can support 10 Gigabit Ethernet at lengths up 33 meters. It is most commonly used for 100 Megabit Ethernet applications.

So OM1 is fairly slow fiber and as to why this is clearly an SFP issue is beyond me but given the options I can understand what they mean.

 photo cable types_zpsnygpxdeu.png

This is a tough one to really nail down the answers however I’m unclear on crossover cables so lets start there. Now, the need for crossover cables has been eliminated with more modern equipment. Gigabit Ethernet was created with a widely used option called Auto-MDIX (automatic medium-dependent interface crossover). This technology detects whether you need a crossover cable or a straight-through cable, and it automatically configures the network interface card accordingly.

Mmkay, still it means that the wires are not configured the same as a normal cat 5 cable which would cause a connection issue.

 photo cable types_zpsnygpxdeu.png

Lots of variables that I’m unclear on in this one.

  • Single mode fiber (i think ive covered this before) – In fiber-optic communication, a single-mode optical fiber (SMF) is an optical fiber designed to carry light only directly down the fiber – the transverse mode. Modes are the possible solutions of the Helmholtz equation for waves, which is obtained by combining Maxwell’s equations and the boundary conditions.
  • multimode fiber – Multi-mode optical fiber is a type of optical fiber mostly used for communication over short distances, such as within a building or on a campus. Typical multi-mode links have data rates of 10 Mbit/s to 10 Gbit/s over link lengths of up to 600 meters. I think this means it can handle several singnels instead one stream
  • longwave sfp – I honestly cant find a definition for these two and C is the answer. I think its a type of module that transmits over fiber but I could be totally off base. I did find one for sale on amazon though, so i suppose thats helpful lol
  • shortwave sfp – yeah no clue.

So thats all for today. I would like to think I will do another post tonight but that may not be true. Who knows, regardless I’m having a good time working hard.

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