Sun System Handbook - ISO 3.4 June 2011 Internal/Partner Edition | |||
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Solution Type Technical Instruction Sure Solution 1009240.1 : Ethernet MDI/MDI-X auto-sensing
PreviouslyPublishedAs 212785 Description Many newer Ethernet switches and NICs support auto-sensing of MDI/MDI-X. This eliminates the need for a crossover network cable when connecting one system directly to another system without a switch, or when connecting a switch to a switch not using a "up-link" port. Steps to Follow When using copper (UTP, RJ45) interfaces, a standard network cable is used when connecting a system to a switch. Such a cable uses one-to-one wiring. Historically, a crossover or MDI-X cable would need to be used when directly connecting a system to another system or switch to another switch. MDI (medium dependent interface) MDI-X (MDI crossover) UTP (Unshielded Twisted Pair copper cable standard) RJ45 ("Western" type ethernet connector) Some switches have the ability to configure a port as a "up-link" or MDI-X port for connecting to another switch using a standard network cable. Some have a dedicated port for this purpose. Interface cards in system historically needed to use a crossover or MDI-X cable to link directly to another system. New generation Ethernet cards and switches use auto-sensing to accomplish this, making the establishment of these links more convenient. Namely, Gigabit Ethernet interfaces have this feature. Current Sun[TM] devices that support auto-sensing of MDI/MDI-X are: ce (GigaSwift) and bge Ethernet Interfaces and B1600 Switch, NETP ports IMPORTANT: MDI/MDI-X cable detection will not work unless auto-negotiation is on or enabled. If auto-negotiation is disabled, auto-MDI/MDI-X pin signal configuration will also be disabled. This means that you will have to use a cross-over cable to connect two systems back to back. If you are connecting to a switch, and the switch doesn't have the ability to configure an up-link port or have a hard wired up-link port, you will also need to use a MDI-X cable. An alternative is to leave auto-negotiation enabled (this is the default setting) but reduce the subset of permitted modes to the single mode that you want to use. For example, to force an uplink to 1000BASE-T and retain MDI/MDI-X auto- sensing, have the port set to negotiate but with "1000full" as the only capability. See also: Technical Instruction <Document: 1005843.1> - Sun[TM] GigaSwift Gigabit Ethernet Adapters First Checks Technical instruction <Document: 1001843.1>- bge Gigabit Ethernet First Checks Product Sun Quad GigaSwift Ethernet UTP Adapter Sun GigaSwift Ethernet PCI Adapter Sun Fire V480 Server Sun Fire V440R Server Sun Fire V440 Server Sun Fire V240 Server Sun Fire V210 Server Sun Fire B1600 Blade System Chassis Internal Comments For the internal use of Sun Employee's. See also TSC Network Product Pages at http://panacea.central.sun.com/net/ce http://panacea.central.sun.com/net/bge http://panacea.central.sun.com/net/ethernet MDI, MDI-X, crossover, uplink, up-link, up, link, auto, negotiation, back, gigabit, ethernet, utp, rj45, down, cable Previously Published As 77124 Change History Date: 2004-07-05 User Name: 25440 Action: Approved Comment: Minor edits ("Ethernet" throughout instead of randomly "Ethernet" and "ethernet", "auto-negotiation" rather than "auto-negotiation", "autonegotiation" and "autoneg", and so on). Publishing. Version: 0 Date: 2004-07-05 User Name: 25440 Action: Accepted Comment: Version: 0 Attachments This solution has no attachment |
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