BroadR-Reach vs 100Base-Tx vs 1000Base-T: A Comparison

This article breaks down the differences between BroadR-Reach, 100Base-Tx, and 1000Base-T Ethernet technologies.

Introduction to BroadR-Reach

BroadR-Reach is a point-to-point Ethernet PHY technology developed by Broadcom. The OPEN Alliance adopted it, specifying full-duplex operation over a single Unshielded Twisted Pair (UTP) cable at 100 Mbps.

Think of BroadR-Reach as a hybrid of 100Base-Tx and 1000Base-T. The key difference lies in the PHY layer; the upper layers of the Ethernet stack and network topology remain identical to the 802.3 standard.

100Base-Tx Features

Here’s a rundown of 100Base-Tx features:

• Signaling: Uses 3-level signaling
• Duplex: Dual simplex
• Modulation: MLT-3, 125 MSPS, 65 to 80 MHz Bandwidth
• Cabling: Two twisted pairs
• Error Correction: Decision Feedback Equalization (DFE)

1000Base-T Features

Let’s look at the characteristics of 1000Base-T:

• Signaling: Uses 5-level signaling
• Duplex: Full duplex
• Modulation: PAM-5, 125 MSPS, 65 to 80 MHz Bandwidth
• Cabling: Four twisted pairs
• Transmit Filter: Partial response transmit filter
• Error Correction: Additional level for error correction coding
• Signal Processing: Echo and crosstalk cancellation in DSP
• Error Correction: Decision Feedback Equalization (DFE)

BroadR-Reach Features

Now, let’s dive into the specifics of BroadR-Reach:

• Signaling: Uses 3-level signaling
• Duplex: Full duplex
• Signal Processing: Echo cancellation
• Modulation: PAM-3, 66.7 MSPS, 33.3 Bandwidth
• Cabling: Single twisted pair
• Error Correction: Decision Feedback Equalization (DFE)

Benefits of BroadR-Reach

BroadR-Reach offers several advantages over traditional Ethernet standards:

• Bandwidth Reduction: Reduces bandwidth by over 2x.
• Lower Quality Cabling: Operates over lower quality cabling.
• Improved Emissions: Permits aggressive filtering for improved emissions and immunity.

Comparison Table

Here’s a table summarizing the key differences: