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Appendix A

Jumbo Packets — Jumbo frames are defined as those packets whose length exceeds the standard Ethernet MTU, which is 1500 kbytes. For the C64x+ devices, it is recommended not to use packets exceeding 35K in length. The PHY that you use can place additional limits on to the length of the packets that you can transfer in a system.

Link — The transmission path between any two instances of generic cabling.

Multicast MAC Address — A class of MAC address that sends a packet to potentially more than one recipient. A group address is specified by setting the LSB of the first MAC address byte. Thus, 01h-02h-03h-04h-05h-06h is a valid multicast address. Typically, an Ethernet MAC looks for only certain multicast addresses on a network to reduce traffic load. The multicast address list of acceptable packets is specified by the application.

Physical Layer and Media Notation — To identify different Ethernet technologies, a simple, three-field, type notation is used. The Physical Layer type used by the Ethernet is specified by these fields:

<data rate in Mb/s><medium type><maximum segment length (×100m)>

The definitions for the technologies mentioned in this guide are as follows:

 

Table A-1. Physical Layer Definitions

Term

Definition

10Base-T

IEEE 802.3 Physical Layer specification for a 10 Mb/s CSMA/CD local area network over two

 

pairs of twisted-pair telephone wire.

100Base-T

IEEE 802.3 Physical Layer specification for a 100 Mb/s CSMA/CD local area network over two

 

pairs of Category 5 unshielded twisted-pair (UTP) or shielded twisted-pair (STP) wire.

1000Base-T

IEEE 802.3 Physical Layer specification for a 1000 Mb/s CSMA/CD LAN using four pairs of

 

Category 5 balanced copper cabling.

Twisted pair

A cable element that consists of two insulated conductors twisted together in a regular fashion to

 

form a balanced transmission line.

Port — Ethernet device.

Promiscuous Mode — EMAC receives frames that do not match its address.

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Glossary

SPRU975B –August 2006

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Texas Instruments TMS320C645x DSP manual Table A-1. Physical Layer Definitions, Term Definition