Category Archives: Copper Networks

Among so many categories of copper cables such as Cat5e, Cat6, Cat6a, Cat7, even Cat8, what kind of cables should you choose? And how to make Ethernet patch cables by yourself? For more copper networks information, check the following articles.

Products Used in the Physical Layer

The Physical Layer, as the Layer 1 of ISO OSI Systems communications model where the mechanical and electrical specifications of physical network interface are defined. The physical network interface is considered passive network elements because they do not generate or alter data units traveling across the network. Network elements defined by the Physical Layer include (among others): Network transport media (cables) and connectors.

Network Media Types

Network media types used in Data Centre today are copper and fibre optic cables.

The following copper cables are available: Cat 1 to Cat 5, Cat 5E, Cat 6, Cat 6a, Cat7 and Twinax cables. Twinax copper cable with two conductors in a coaxial cable, which is slowly wrapped around each other; originally designed to replace RS-232 and has been redesigned for high-speed computer applications under 10 meters.

Fibre optic cable utilize light for data transmission, rather than electrical current on copper cables, Fibre optic cables have many advantages, for example, the are many times lighter and have substantially reduced bulk, no pins, a smaller and more reliable connector reduced loss and distortion, and are free from signal skew or the effects of electro-magnetic interference.

Cable Connector Types

Copper cable connectors. Currently, there are two copper connector standards are in use, RJ-45 and MRJ-21.

RJ-45: The most popular Ethernet connector in use nowadays. MRJ-21: Used in Brocade’s netlron MLX product family, provides 1GbE connectivity of up to 6 ports by the RJ-45 patch panel or RJ-45 connectors. It is a high-density, high-speed copper cable.

Optical cable connectors. Optical cable connector structure can be divided into: FC,SC, ST, LC, D4, DIN, MU, the MTP,MPO and so on in various forms.

Transceivers Are Either Copper or Optical

Copper transceivers, copper medium usually does not require any transceivers, as they are a part of the interface module. However, few of Brocade’s products use a copper SFP with an RJ-45 female connector for 1 GbE connectivity over copper medium, or XFP copper transceiver for 10GbE connectivity over CX4 copper. Figure 1 is a 1000BASE-T Gigabit Ethernet Full Duplex RJ45 100m Copper SFP Optical Transceiver.

copper sfp

Figure 1. Copper SFP Optical Transceiver

  • XFP 10GBASE-CX4: Uses a CX4 connector to provide a connection to up to 15 meters over CX4 grade copper cable.
  • SFP 1000BASE-TX: Uses a RJ-45 connector to provide a connection to up to 100meters over Cat5e or higher copper cable.
Optical transceivers.

The following optical transceivers are available: (Figure 2 is a CWDM SFP 40km Single-Mode Optical Transceiver)

cwdm sfp

Figure 2. CWDM SFP Optical Transceiver

  • SFP: Small form-factor Pluggable. Supports 100Mbps and 1Gbps Ethernet.
  • SFP+: Small Form-factor Pluggable Plus. Looks are physically identical to the SFP port but support higher speeds. Supports 10Gbps Ethernet. Might also support SFP transceivers.
  • XFP: 10 Gigabit Small Form-factor Pluggable. Supports 10Gbps Ethernet.
  • XENPAK: XENPAK transceiver is a hot-swappable I/O devices that plug into 10-Gigabit Ethernet module ports. The XENPAK transceiver is available in either optical or copper interfaces. It is used in typical router line card applications, storage, IP network and LAN.
  • X2: X2 transceiver is a standardized form factor for 10 Gb/s fibre optic transceivers that is used for data transfer rates from 10.3 Gb/s to 10.5 Gb/s. X2 transceiver is used in datacom optical links only (not telecom), and they are smaller than old generation XENPAK transceiver.
  • GBIC) Transceiver: A gigabit interface converter (GBIC) transceiver can send and receive data, which is to digitally convert media between a gigabit Ethernet network and a separate fibre optic based network.

SFP+ Twinax cables are copper cables with two SFP+ transceivers attached on either end. They are also known as Direct Attach Cables (DAC). Using SFP+ Twinax cable is significantly cheaper than connecting devices using two 10Gbps fibre optic transceivers over fibre cable. There are two types of SFP+ Twinax cables: active and passive. SFP+ Twinax cable provided by fs.com is available in lengths of 1m, 2m, 3m, 5m.

In addition, all those copper or optical products used in the Physical layer can be found in fs.com.

The Core Technology Of WIRING

1. High-precision Optical Time Domain Reflectometer(ODTR)

OTDR Price technology through sending a test signal in the measured line while monitoring signal in the line of reflection phase and intensity. If the signal through the cable encounter mutation of an impedance, part or all of the signals will be reflected back, the reflected signal delay, size and polarity indicate the discontinuity position and feature of the special impedance in the cable.

2. Split Pairs

UTP(Unshielded Twisted Pair) cable is two insulated Copper Ethernet Cable twisted together to each other by a certain density, which reduces the degree of signal interference, each wire in the transmission of radiation waves are offset by radio waves from the other line.

The so-called split pairs is the original two pairs are opened and yet again to reform a new pair. Because when this failure occurs, the end-to-end connectivity is good, so use a multimeter or hand tool such tools can not check it out. Only with a dedicated cable tester to check it out. Since crosstalk on the related lines of no kink, so online pairs when signal through will produce a high near-end crosstalk (NEXT).

Split pairs normally also be used, but often crosstalk index is large, only to run in the 10M application, can not achieve the 100M application.

3. The Standard Twisted Pair Terminations

Twisted pair eight lines are inserted into the plug (or termination) according to the standard. There are two termination criteria: EIA/TIA T568A/T568B, no essential difference between them, but the difference between color. The natural problem of termination is to ensure that: 1, 2 are a pair; 3, 6 are a pair; 4, 5 are a pair; 7, 8 are a pair. Note: Do not one cable end with T568A, but the other end with T568B. The mix use of T568A/T568B is a special connection method of cross connection. Projects more use T568B wire method.

In Ethernet, Pin1, Pin2 is a twisted pair responsible for network data transmission, Pin3, pin6 is a twisted pair responsible for network data reception, so 1, 2 a pair, 3, 6 a pair, 4, 5 a pair, 7, 8 a pair, it is a must, and not 1, 2, 3, 4, 5, 6, 7, 8 pairs, so called split pairs, will lead to serious signal leakage.

4. Wire Map

Ware Map: This is to confirm the integrity of link connection, mainly to check each pair of 8-core Twisted Pair Cable whether meets the required standards EIA/TIA- 568A/568B, whether the wire at both ends of cable is matching. If wrong, there are five cases include open circuit, short circuit, crossed pairs, reversed pair and split pairs.

● Open circuit: refers to the phenomenon of line off, generally due to bad crystal head cable connection, common with the cable test equipment can locate the fault point.

● Short circuit: refers to one or more wires touch each other in a metal core, resulting in a short circuit.

● Crossed pairs: refers to wire at both ends error in the routing process, which is one end with 568A and the other end with the 568B, usually such wire method used in network equipments level, or network cards connection, but as a general wiring to say, as long as the two ends of the wire method consistent, as for the module wire method can refer to the color above.

● Reversed pairs: this error is due to both ends of a pair line connected to the positive and negative error, is generally believed that the odd line number for the positive electrode, the even line as the negative electrode, for example, 568B Pin1 orange white lines to the first pair of positive, Pin2 Orange Line is negative, it can form a direct current loop, reverse connection is positive and negative confused in the same pair line.

● Split pairs: this is one of the common wire error, which is not strictly comply with wire standard, it is specified in the standard that 1, 2 is the first pair, 3, 6, is the second pair, if 3, 4 into the second pair will cause large signal leakage, which produces NEXT (near end crosstalk), this will cause the user’s Internet difficulties or indirect interrupts, especially in the 1000Mbps network it is particularly obvious.

The Troubleshooting Of Fiber Optics

Fiber optics once just meet the needs of high performance systems, but now it has widely spread in various types of networks. If you are familiar with Network Cabling, then you will soon find that fiber is a kind of something completely different. Not only because of its installation process is quite different with copper wiring, and troubleshooting methods also have very big differences. Compared with copper wire, fiber optics is more fragile, so there will be some potential failures exist when use.

The Most Common Troubleshootings In Fiber Optics

Any network professionals who have done network troubleshooting are clear that this is a complex process. So know where to start looking for faults is very important. Here are some of the most common fiber failures and the possible factors cause these faults, the information will help users to predict the network faults with bases.

Fiber break is usually due to external physical extrusion or excessive bending;

Transmission power shortage;

The Optical fiber laying distance is too long may cause a loss of signal;

Connector damage may result a loss of signal;

Fiber Optic joints and connectors faults may cause a loss of signal;

The excessive use of fiber optical joints and connectors may cause a loss of signal;

Fiber patch panel or splice tra connection failure;

Generally speaking, if the connection is completely unreasonable, then it may be fiber breakage. But if the connection is intermittent, may be the following reasons:

Poor junction levels or multiple junction times cause serious optical attenuation;

The dust, scratches, fingerprints, humidity and other factors damage the connector;

The transmission power is too low;

Connector errors in the Distribution Cabinet.

Collecting Information

Collecting the fault performance and the basic information of possible causes. Using any available means, the key of troubleshooting is to get valuable information by asking the right questions.

The following are some of the problems should be first asked.

If anyone had moved the fiber (dismantling or reconnect) or moved the PC recently?

Find out whether recently PC is disconnected or be moved is very important. If the fiber optical cable is disconnected from the PC, then it is likely that the cable simply has not been properly connected, or problems occur when reconnection, or the fiber may damage when disconnect.

Whether the device recently was moved?

Most copper network failures are caused by someone walking too fast to the original sticking wall table, or cleaners accidentally move the table to do vacuum cleaning. Moving the table without unplug the network cable, the cable is likely to be excessive dragged, or is held down by table or folded. If such action would damage to a copper wire, then you can imagine what consequences will be brought to the fiber, as it is made ​​of glass.

The vast majority of users are not clear that Fiber Optics Cable will break in the situation of stepped on or bend too much.

MSA to Boost 400Gbps Copper Network Cable and Optical Fibre Transceiver Market

Five leading global companies plan to come to an agreement of multiple sources (multi – source agreement, MSA) to create CDFP (400Gbps form – factor pluggable) industry alliance, defines fibre optic transceiver module/plug and mainboard electric mechanical dimension edge connector .

New CDFP MSA aims to regulate and encourage 400Gbps hot swap module’s  development and commercialization, this module integrates 16 transport channels to receive 16 channels, supports passive and active copper networks, as well as the active fibre optic module.

Brocade, senior technical personnel said: “we expect this high integration fibre optic transceiver module allows network equipment maker has high density and higher data throughput of 400Gbps system solutions, MSA group plans to develop specification details, to promote the industry using compatible high density products.

CDFP MSA vendors are interchangeable in terms of mechanical and electrical products, this project will set electrical interface, optical interface and mechanical interface, may include optical fibre connector and plug with cable plug, electrical connectors, guide rail, the front panel and the main PCB layout requirements. Moreover, MSA specification is expected to include thermal, electromagnetic and electrostatic discharge design.

Molex group product manager Scott Sommers, said: “through the establishment of the front panel, the hot swap of 16 channel 400Gbps module of multiple sources of compatible, the collaboration is committed to increasing customer choice and ensure interoperability and interchangeability, fundamentally promote the whole copper and fibre optic transceiver market more rapid development.”

For more information about copper network cable and optical fibre transceiver, please visit our website: www.fs.com.