Home > Articles > Networking > Network Design & Architecture

Installing and Testing Copper Cabling in LANs

  • Print
  • + Share This
This chapter describes issues related to installing and testing copper physical media for use in local area networks, primarily twisted-pair cabling.
This chapter is from the book

The OSI Model places the medium as being below the Physical Layer (see Figure 2-1). Each individual implementation of Ethernet specifies parameters for the intended medium, but usually references other cable related standards as part of that description. This chapter and Chapter 3, "Fiber Optic Media," are about the medium itself (copper and fiber, respectively).

Figure 2-1

Figure 2-1 Copper and fiber optic media in relation to the OSI Model

Standards

Until the release of ANSI/TIA/EIA's Telecommunications Systems Bulletin 67 (TSB67), there were no standards for field testing the performance of installed twisted-pair LAN cable. All the older standards (prior to TIA/EIA-568-A TSB67, which was approved in October 1995) were designed to verify either raw cable or connecting hardware components—but did not apply to a cable assembly or an installed cable link.

Information about links in general, and information specific to twisted-pair LAN cables, is provided in the text that follows. Note that the term link is used to describe installed assemblies of cabling components; that is, connectors and cable.

As the networking industry matures, it is interesting to note which technologies emerge as dominant and to track which specifications and technologies are omitted. For example, one of the earlier documents that defined cable requirements for networking applications was the Underwriters Laboratories document "UL's LAN Cable Certification Program" (see Table 2-1). This document reviewed IBM's Cabling System Technical Interface Specification (GA27-3773-1) for 150 ohm cables, such as Type 1 and Type 3 cable. It also provided detailed performance requirements for the following cable types that have evolved into the current Category 3 and Category 5 cables referenced by TIA/EIA-568-A.

Table 2-1. Early 1980s Underwriters Laboratories LAN cable grades (historical reference only)

Cable Grade

Operating Frequency

Use

Level I

(No performance criteria found)

Telephone and power-limited circuits

Level II

Up to 1MHz

Similar to IBM Type 3

Level III

150kHz to 16MHz

Approximately the same as Category 3

Level IV

772kHz to 20MHz

Slightly better than Category 3, never widely adopted

Level V

772kHz to 100MHz

Approximately the same as Category 5

Category 3 and Category 5e are the only ones described by the 2001 release of TIA/EIA-568-B (see Table 2-2). Category 5 is explicitly described as a legacy cable specification. Depending on how cheap Category 5e becomes, and on how tenacious the low-speed protocols are (such as 10BASE-T), Category 3 is likely to disappear entirely, or may be used for technologies such as telephone and xDSL. TIA/EIA-568-B includes a statement to the effect that although 150 ohm (STP-A) cable is still mentioned, it is not recommended and is very likely to be removed from the next full release of the TIA standards entirely. An example of how cabling standards evolve is provided in Table 2-3.

Table 2-2. ISO/IEC 11801 and TIA/EIA-568 cable grades for balanced cable as of March 2008

ISO/IEC Cable Grade

Operating Frequency

TIA/EIA Cable Grade

Operating Frequency

Class A

Up to 100KHz

Class B

Up to 1MHz

Class C

Up to 16MHz

Category 3

Up to 16MHz

Class D

Up to 100MHz

Category 5e

Up to 100MHz

Class E

Up to 250MHz

Category 6

Up to 250MHz

Class EA

Up to 500MHz is proposed

Category 6A

Up to 500MHz

Class F

Up to 600MHz

Class FA

Up to 1000MHz is proposed

Table 2-3. Evolution of high-speed twisted-pair link specifications as extracted from the obsolete TIA/EIA-568-A standard, the current TIA/EIA-568-B.2 and TIA/EIA-568-C.2 standards

TIA/EIA-568-A

TIA/EIA-568-B

TIA/EIA-568-C

TSB67

TSB95

Addendum 5

TIA/EIA-568-B.2-1

TIA/EIA-568-C.2

"Old" Cat 5

"New" Cat 5

Cat 5e

Cat 6

Cat 6A

Frequency Range

1–100MHz

1–100MHz

1–100MHz

1–250MHz

1–500MHz

Propagation Delay

Not Specified

Specified

Same as TSB95

Same as TSB95

Same as TSB95

Delay Skew

Not Specified

Specified

Same as TSB95

Same as TSB95

Same as TSB95

Attenuation

Specified

Same as Cat 5

Same as Cat 5

43 percent better

43 percent better

NEXT

Specified

Same as Cat 5

41 percent better

337 percent better

337 percent better

PS NEXT

Not Specified

Not Specified

Specified

216 percent better

216 percent better

ELFEXT

Not Specified

Specified

5 percent better

104 percent better

104 percent better

PS ELFEXT

Not Specified

Specified

Same as TSB95

95 percent better

95 percent better

Return Loss

Not Specified

Specified

26 percent better

58 percent better

58 percent better

The following list of standards is only a small part of what is available, but it represents some of the most likely standards of interest for a network support staff library.

  • International Standards
  • ISO/IEC 11801: IT—Cabling for customer premises
  • ISO/IEC 18010: Information technology—Pathways and spaces for customer premises cabling
  • ISO/IEC 14763-1: Information technology—Implementation and operation of customer premises cabling—Part 1: Administration, documentation, records
  • ISO/IEC 14763-2: Information technology—Implementation and operation of customer premises cabling—Part 2: Planning and Installation practices
  • ISO/IEC 61935-1: Testing of balanced communication cabling in accordance with ISO/IEC 11801—Part 1: Installed cabling
  • ISO/IEC 61935-2: Testing of balanced communication cabling in accordance with ISO/IEC 11801—Part 2: Patch cords and work area cords
  • United States Standards
  • ANSI/TIA/EIA-568-B.1: Commercial Building Telecommunications Cabling Standard
  • ANSI/TIA/EIA-568-B.2: 100 Ohm Twisted Pair Cabling Standard
  • ANSI/TIA/EIA-569-A: Commercial Building Standard for Telecommunications Pathways and Spaces
  • ANSI/EIA/TIA-570-A: Residential Telecommunications Cabling Standard
  • ANSI/TIA/EIA-606-B: Administration Standard for the Telecommunications Infrastructure of Commercial Buildings
  • ANSI/TIA/EIA-607-A: Commercial Building Grounding and Bonding Requirements for Telecommunications
  • ANSI/TIA-758-A: Customer-Owned Outside Plant Telecommunications Infrastructure
  • ANSI/TIA/EIA-862-A: Building Automation Systems Cabling Standard for Commercial Buildings
  • ANSI/TIA/EIA-942: Telecommunications Infrastructure Standard for Data Centers
  • ANSI/TIA-1005: Telecommunications Infrastructure Standard for Industrial Premises

ANSI/TIA/EIA-568-B, an update/replacement for ANSI/TIA/EIA-568-A (the Commercial Building Telecommunications Cabling Standard) requires better link performance by specifying much more stringent tests to support ever-faster networking demands, such as Gigabit and 10 Gigabit Ethernet (see Table 2-4). Unlike the earlier version, TIA/EIA-568-B was published in three sections. TIA/EIA-568-B was updated regularly following release.

  • Part 1 (TIA/EIA-568-B.1, General Requirements) covers general requirements for planning and installing a structured cabling system. That is, everything from the configuration and requirements for the rooms that house the cable and equipment (see also ANSI/EIA/TIA-569-A), up through the electrical safety requirements (see also ANSI/TIA/EIA-607 and ANSI/TIA/EIA-758) and the actual network cable selection, installation, and testing requirements for both twisted-pair copper and fiber optic cables.
  • Part 2 (TIA/EIA-568-B.2, Balanced Twisted-Pair Cabling Components) is mostly concerned with the connecting hardware and cable components used in 100 ohm twisted-pair copper cable networking applications. Several appendixes define the testing requirements for those components and for testing cable assemblies (patch cables and horizontal cabling). Updates have been released regularly, such as TIA/EIA-568-B.2-1, which was approved in June 2002 as Addendum 1 to the basic standard, and defines the performance specifications and test requirements for Category 6 cable and components. Addendum 10 defines Augmented Category 6 (Cat 6A) link performance requirements (approved February 2008).
  • The TIA published Technical System Bulletin 155 (TSB-155) to define the cabling performance and field test requirements for the 10GBASE-T application as defined in IEEE standard 802.3an. Note that Category 6A demands a higher level of performance than TSB-155 in the frequency range from 250 to 500MHz and especially for "Alien Crosstalk."

Table 2-4. Required test parameters for 10GBASE-T support for TIA and ISO cabling standards

TIA/EIA-568-B and TSB-155

ISO/IEC 11801 and TR -24750

Wiremap

M

M

DC Loop Resistance

I

M

Length

M

I

Propagation delay

M

M

Delay skew

M

M

Insertion loss

M

M

Return loss measured from both ends

M (1)

M (1)

Near-end crosstalk (NEXT) loss pair-to-pair measured from both ends

M

M (2)

Power sum near-end crosstalk loss (TIA) PSNEXT (ISO) PS NEXT calculated for both ends

MC

MC (2)

Attenuation to Crosstalk loss Ratio Near-end (TIA) ACRN, (ISO) ACR-N

NR

MC

Power Sum Attenuation to Crosstalk Loss Ratio Near-end (TIA) PS ACRN (ISO) PSACR-N

NR

MC

Attenuation to Crosstalk Loss Ratio Far-End (TIA) ACRF, (ISO) ACR-F (formerly ELFEXT) pair-to-pair

M

MC

Power Sum Attenuation to Crosstalk Loss Ratio Far-End (TIA) PSACRF (ISO) PS ACR-F (formerly PSELFEXT)

MC

MC

Alien Near-end Crosstalk (ANEXT) Loss

M

M

Power-Sum Alien Near-End Crosstalk Loss (TIA) PSANEXT (ISO) PS ANEXT

MC

MC

AFEXT loss

M

-

Power Sum Attenuation to Alien Crosstalk Ratio Far-End (TIA) PSAACRF (ISO) PS AACR-F

M

M

Average PSANEXT Loss

M

NR

Average PSAACRF

M

NR

I = Informational, M = Mandatory, MC = Mandatory (Calculated), NR = Not required by this standard

M (1) = If measured insertion loss value at the same frequency is less than 3dB, the value is not used for Pass/Fail criteria

M (2) = If measured insertion loss value at the same frequency is less than 4dB, the value is not used for Pass/Fail criteria

Note: Informational parameters are measured but not used for Pass/Fail criteria

The TIA/EIA-568-C standard update should be completely approved and published by Q3 2009. As with TIA/EIA-568-B, the document structure was reorganized. This text utilizes primarily TIA/EIA-568-B references and final test requirements because full approval for TIA/EIA-568-C had not occurred before the book went to press, and the requirements could still change.

  • Part 0 (TIA/EIA-568-C.0) covers generic requirements for planning and installing a structured cabling system. Included are general requirements for architecture, length, grounding, bend radius, pulling tension, pinout, and polarity. Also included are general testing requirements.
  • Part 1 (TIA/EIA-568-C.1) covers requirements for cable systems in a commercial building, or between commercial buildings in a campus environment. Provides the configuration and requirements for the rooms that house the cable and equipment (see also ANSI/EIA/TIA-569-A), up through the electrical safety requirements (see also ANSI/TIA/EIA-607 and ANSI/TIA/EIA-758) and the actual network cable selection and installation requirements for both twisted-pair copper and fiber optic cables.
  • Part 2 (TIA/EIA-568-C.2) covers the connecting hardware and cable components used in balanced twisted-pair cable networking applications. Provides the requirements and test specifications for components used to create an installed link, as well as the testing requirements for installed links.
  • Part 3 (TIA/EIA-568-C.3) covers optical fiber topics. (See Chapter 3.)
  • + Share This
  • 🔖 Save To Your Account