Microsoft KB Archive/278870

= Using Crossover Cables in Home or Peer-to-Peer Networks =

Article ID: 278870

Article Last Modified on 1/29/2007

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APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional
 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows Millennium Edition
 * Microsoft Windows 98 Second Edition
 * Microsoft Windows 98 Standard Edition
 * Microsoft Windows 95
 * Microsoft Windows 3.1 Standard Edition
 * Microsoft Windows 3.11 Standard Edition
 * Microsoft Windows for Workgroups 3.1
 * Microsoft Windows for Workgroups 3.11

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This article was previously published under Q278870



SUMMARY
Microsoft Networking is based on the Ethernet 802.3 standard (Carrier Sense Multiple Access with Collision Detection). The Ethernet 802.3 standard does not specifically forbid the use of crossover cables, but the implementation of crossover cables is beyond the scope of the standard.

Microsoft will make every reasonable effort to assist you in troubleshooting home or peer-to-peer networking issues. However, if you use crossover cables when you configure your home or peer-to-peer network, Microsoft does not guarantee that issues will be resolved.



MORE INFORMATION
When you work with a network that uses crossover cables, you must perform all of the troubleshooting that is done with standard cables and a hub. Even if you strongly suspect that a particular issue may be related to the use of a crossover cable, you must not limit the amount of troubleshooting to be performed on the network.

The Ethernet 802.3 standard specifications had been originally designed for use with 10Base5 (ThickNet) Ethernet using RG-8 or RG-11 cabling and an attachment unit interface\ Ethernet DIX (AUI\DIX) connector on the back of the network adapter (sometimes called a network interface card or NIC).

Cost considerations led to the widespread adoption of 10Base2 (ThinNet) Ethernet using RG-58 cabling connected to a BNC connector on the back of the network adapter. In the case of both 10Base5 and 10Base2 Ethernet, you can assume that given the manner in which the network adapters are attached to the network, the network adapters are &quot;daisy chained&quot; with no intermediary devices required (for example, drop cables to a backbone on ThickNet or T-connectors on ThinNet). For this reason, a network adapter with AUI/DIX or BNC connectors must implement collision detection to be in compliance with the Ethernet 802.3 standard specifications.

Cost considerations also led to the even wider adoption of 10BaseT Ethernet using category 3 (Cat3) unshielded twisted pair (UTP) cable connected to hubs. The use of hubs no longer made it a requirement that each network adapter do collision detection as that function is required in the hub and &quot;daisy chaining&quot; one network adapter to another longer needed to be a consideration in network adapter design. Even though the 10BaseT addendum to the Ethernet 802.3 standard specifications recommends that collision detection be implemented in the network adapter, it is not a requirement for manufactures of a network adapter to follow this recommendation to bring, for example, a 10BaseT network adapter in compliance with the Ethernet 802.3 standard specifications.

In some cases, the use of crossover cables can enhance the throughput of the network, and is ideally suited for router-to-router connections where the network adapter is in use and both ends of the segment are full-duplex.

For more information about local area network (LAN) topology and crossover cables, refer to the following Microsoft Web site:

Microsoft Developer Network Online

