question: Why do routers wear out?
comment: Lots of people store routers in cupboards or have blocked vents where they can't cool down. Mine sits in the open as a feature to stay cool. Thermal damage will happen otherwise. They should last many years
passages: As a cost-cutting measure, as well as to satisfy FCC rules that prohibit fitting external antennas with higher gain, the design of the latest version of the WRT54G no longer has detachable antennas or TNC connectors. Instead, version 8 routers simply route thin wires into antenna 'shells' eliminating the connector. As a result, Linksys HGA7T and similar external antennas are no longer compatible with this model.
  
  Until version 5, WRT54G shipped with Linux-based firmware.
  
  Section::::Hardware and revisions.:WRT54GS.
   In 2015 Juniper Networks announced the 2016 end-of-life for all T-series routers other than T4000. The other models in the series are superseded by the PTX-series core routers and MX-series edge routers, except for applications that require legacy protocols like SONET or ATM.
  
  Section::::Models and platforms.
  
  The Juniper T-series routers which consists of T320, T640, T1600, T4000, TX Matrix and TX Matrix Plus has thousands of units deployed by the major telecom and ISP networks around the world.
  
  Section::::Models and platforms.:T320.
   Degenerative failures are those caused by the slow deterioration of performance over time.
   BULLET::::- Safety glasses and ear protection should be worn at all times when using a router.
  
  BULLET::::- Only trained adults, or trained adolescents with supervision, should use the router.
  
  Section::::Moulding.
   BULLET::::- Short operational life. In the most common applications, valves have a working life of just a few thousand hours, much shorter than solid state parts. This is due various commonplace failure mechanisms: cathode depletion, open or shorts circuits—notably of the heater and grid structures, cathode poisoning, and physical breakage of the glass envelope. Heater failure most often happens due to the mechanical stress of a cold start. Only, in certain always-on professional applications such as specialized computing and undersea cables, specially designed valves in carefully designed circuits and well cooled environments reached operational lives of tens or hundreds of thousands of hours.
   On the first pass, the connection of all conductors is performed, regardless of the presence of conflicts, which consist in crossing the conductors on one layer and breaking the gaps. On each subsequent pass, the auto-router tries to reduce the number of conflicts by breaking and re-building connections (the ripup-and-retry router method) and pushing the conductors by pushing the neighboring ones (the push-and-shove router method). Electromagnetic compatibility can be tested in Specctra through the “SPECCTRAQuest SI Expert” module.
   Because stone dust is very abrasive these routers also have much better protection for the guide rails. With "wood" routers the guide rails are often visible from the outside & unprotected, while stone routers are fully covered.
  
  Stone routers also have a water recirculation system. A small jet of water is pointed at the router bit and this captures almost all fine stone dust in the water, which then flows to a collection reservoir where the stone particles settle on the bottom.
  
  Section::::Types of materials.:Polyurethane foam.
   The WRT1900ACS was released 8. October 2015. It looks identical to the WRT1900AC, but has a 1.6 GHz dual core CPU (Same CPU as WRT1200AC/WRT1900AC v2, but overclocked to 1.6 GHz). Like the WRT1900AC v2, it has 512 MB of RAM.
  
  In January 2016, DD-WRT became available for the WRT1900ACS, as well as both versions of the WRT1900AC.
  
  Section::::Specifications and versions.:WRT3200ACM.
   A CNC wood router uses CNC (computer numerical control) and is similar to a metal CNC mill with the following differences:
  
  BULLET::::- The wood router typically spins faster — with a range of 13,000 to 24,000 RPM
  
  BULLET::::- Professional quality machines frequently use surface facing tools up to 3" in diameter or more, and spindle power from 5 to 15 horsepower. Machines capable of routing heavy material at over a thousand inches per minute are common.
   Linksys routers
  
  Linksys manufactures a series of network routers. Many models are shipped with Linux-based firmware and can run third-party firmware. The first model to support third-party firmware was the very popular Linksys WRT54G series.
  
  The Linksys WRT160N/WRT310N series is the successor to the WRT54G series of routers from Linksys. The main difference is the draft 802.11n wireless interface, providing a maximum speed of 270 Mbit/s over the wireless network when used with other 802.11n devices.
  
  Section::::Specifications and versions.
  
  Section::::Specifications and versions.:BEFW11S4.
  
  Linksys' first series of wireless routers.
   Section::::Passive element failures.
  
  Section::::Passive element failures.:Resistors.
  
  Resistors can fail open or short, alongside their value changing under environmental conditions and outside performance limits. Examples of resistor failures include:
  
  BULLET::::- Manufacturing defects causing intermittent problems. For example, improperly crimped caps on carbon or metal resistors can loosen and lose contact, and the resistor-to-cap resistance can change the values of the resistor
  
  BULLET::::- Surface-mount resistors delaminating where dissimilar materials join, like between the ceramic substrate and the resistive layer.
  
  BULLET::::- Nichrome thin-film resistors in integrated circuits attacked by phosphorus from the passivation glass, corroding them and increasing their resistance.
   Section::::Fixed resistor.:Metal oxide film.
  
  Metal-oxide film resistors are made of metal oxides which results in a higher operating temperature and greater stability/reliability than Metal film. They are used in applications with high endurance demands.
  
  Section::::Fixed resistor.:Wire wound.
   A CNC router can reduce waste, the frequency of errors, and the time the finished product takes to get to market. 
  
  Section::::Applications.
  
  A CNC router can be used in the production of many different items, such as door carvings, interior and exterior decorations, wood panels, sign boards, wooden frames, moldings, musical instruments, furniture, and so on. In addition, the CNC router helps in the thermoforming of plastics by automating the trimming process. CNC routers can help ensure part repeatability and sufficient factory output.
  
  Section::::Process.
   Whole installations on a single RCD, common in older installations in the UK, are prone to "nuisance" trips that can cause secondary safety problems with loss of lighting and defrosting of food. Frequently the trips are caused by deteriorating insulation on heater elements, such as water heaters and cooker elements or rings. Although regarded as a nuisance, the fault is with the deteriorated element and not the RCD: replacement of the offending element will resolve the problem, but replacing the RCD will not.
   In those circuits, there is not continuous control of the coupling networks that transfer the recovered energy to the source. In our method, the required resistive characteristic is obtained by the continuous control of the loss-free, storage-less two ports.
  
  Section::::Properties of LFR.
   The original WRT54G was first released in December 2002. It has a 4+1 port network switch (the Internet/WAN port is part of the same internal network switch, but on a different VLAN). The devices have two removable antennas connected through Reverse Polarity TNC connectors. The WRT54GC router is an exception and has an internal antenna with optional external antenna.
   There is some controversy surrounding the existence of the phenomenon known as "cable stretch". Newly installed cables can seem to elongate, requiring readjustment. While it is generally agreed that inner wires actually stretch very little - if at all - housings and linings may compress slightly, and all parts may generally "settle in". Lightweight assemblies such as those used on bicycles are more susceptible to this phenomenon. 
  
  Section::::Uses.
  
  BULLET::::- Sustain pedal linkage on Wurlitzer electric pianos
  
  BULLET::::- Bicycle brakes and gear shift cables
  
  BULLET::::- Photographic shutter release cables
   Channel routers were one of the first forms of routers for integrated circuits, and were heavily used for many years, with YACR perhaps the best known program. However, modern chips have many more than 2 interconnect layers. Although the effort was made to extend channel routers to more layers, this approach was never very popular, since it did not work well with over-the-cell routing where pins are not movable. In recent years, area routers have in general taken over.
   As of January 2006, most third-party firmware is no longer compatible with version 5 of both the WRT54G and the WRT54GS. The amount of flash memory in the version 5 devices has been reduced to 2 MB, too small for current Linux-based third-party firmware. (See table above for information on identifying the version based on the serial number printed on the bottom of the unit, and on the outside of the shrink-wrapped retail box.)
   These routers were repackaged versions of the 2500 specifically to be sold through channel partners to small and medium businesses that needed a greater ease of setup. They were offered at a reduced price due to their reduced software feature set. They are characterized by a light grey/cream colored case compared to the standard dark grey colouring.
  
  Section::::Mission-Specific Routers.
   The "density" of a channel, defined for every "x" within the channel, is the number of nets that appear on both the left and right of a vertical line at that "x". The maximum density is a lower bound on the height of the channel. A "cyclic constraint" occurs when two pins occur in the same column (but with different orders) in at least two columns. In the example shown, nets 1 and 3 suffer from cyclic constraints. This can only be solved by "doglegs" as shown on net 1 of the example.
   BULLET::::- RouterOS v4: October 2009 - March 2011 (based on Linux 2.6.26 kernel)
  
  BULLET::::- RouterOS v3: January 2008 - October 2009 (based on Linux 2.4.31 kernel)
  
  Section::::Product vulnerabilities.
  
  On 23 May, 2018, Cisco Talos Intelligence Group reported that some MikroTik devices were found vulnerable to the VPNFilter malware. MikroTik routers have been compromised by Coinhive cryptocurrency malware.
  
  Section::::Product acceptance.
  
  For market support, the company has established a network of resellers and training associates who issue varies certifications to industry professionals.
   The E4200 also marks the first radical change in the design of the Linksys series since Cisco launched the winged "spaceship" design first seen on the WRT400N. The E4200 features a minimalistic, streamlined design with only a white status LED visible on the top. All traffic activity LEDs and buttons have been relocated to the rear of the device.
   Irrespective of signal state the signal lines are always in low impedance state with respect to one another by virtue of the terminating resistors at the end of the bus.
   patch was made available through their downloads section that provided some level of correction, but it was not a complete fix and the issue would resurface intermittently. When the issue was originally reported, D-Link seemed to have misunderstood that the same issue has been discovered by the Linux community at large to be common across a number of their router models and they failed to provide a complete fix across the board for all adsl router models. 
  
  Section::::Similar models.
  
  The DSL-G624T, DSL-G664T and DSL-G684T routers are very similar to the G604T.
  
  Section::::References.
  
  BULLET::::- Notes
  
  BULLET::::- Review, Test Freaks
  