Low Latency 100-Gbps Ethernet IP Core User Guide

ID 683160
Date 4/15/2021
Public
Document Table of Contents

3.5. Ethernet Glossary

Table 48.  Ethernet Glossary Provides definitions for some terms associated with the Ethernet protocol.

Term

Definition

BIP

Bit Interleaved Parity. A diagonal parity field which is carried in the periodic alignment markers on each virtual lane, allowing isolation of a bit error to a physical channel.

CAUI

100 gigabit attachment unit interface. (C is the symbol in Roman Numerals for 100). This is an electrical interface that which is based on a 10‑lane interface with a bandwidth of 10 Gbps per lane. (In this implementation, the PMA multiplexes the 20 PCS lanes into 10 physical lanes.

CGMII

100 gigabit media independent interface. (C is the symbol in Roman Numerals for 100). This is the byte‑oriented interface protocol that connects the PCS and MAC.

DIC

Deficit Idle Counter. A rule for inserting and deleting idles as necessary to maintain the average IPG. The alternative is to always insert idles which could lead to reduced bandwidth.

FCS

Frame Check Sequence. A CRC-32 with bit reordering and inversion.

Frame

Ethernet formatted packet. A frame consists of a start delimiter byte, a 7 byte preamble, variable length data, 4‑byte FCS, and an end delimiter byte.

IPG

Inter Packet Gap. Includes the end of frame delimiter and subsequent IDLE bytes up to, but not including the next start of frame delimiter. The protocol requires an average gap of 12 bytes.

MAC

Media Access Control. Formats a user packet stream into proper Ethernet frames for delivery to the PCS. The MAC generates the FCS and checks and maintains the IPG.

MII

Media Independent Interface. The byte‑oriented protocol used by the PCS. Sometimes distinguished with roman numerals, XGMII (10), XLGMII (40), CGMII (100).

Octet

Byte. Note that Ethernet specifications primarily use least significant bit first ordering which is opposite from the default behavior of most contemporary CAD tools.

PCS

Physical Coding Sublayer. Presents the underlying hardware as a byte‑oriented communication channel.

XLAUI

40 gigabit attachment unit interface. (XL is the symbol in Roman Numerals for 40). This is an electrical interface that which is based on a 4‑lane interface with a bandwidth of 10 Gbps per lane.

XLGMII

40 gigabit media independent interface. (XL is the symbol in Roman Numerals for 40). This is the byte‑oriented interface protocol that connects the PCS and MAC.

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