User Manual

Bit 47

 

 

 

 

bit 0

1st byte

2nd byte

3rd byte

4th byte

5th byte

6th byte

 

OUI code

 

 

Serial number

 

Table 3-3 Ethernet MAC address

The first bit of the first byte in the Destination address (DA) determines the address to be a Unicast (0) or Multicast frame (1), known as I/G bit indicating individual (0) or group (1). So the 48-bit address space is divided into two portions, Unicast and Multicast. The second bit is for global-unique (0) or locally-unique address. The former is assigned by the device manufacturer, and the later is usually assigned by the administrator. In practice, global-unique addresse s are always applied.

A unicast address is identified with a single network interface. With this nature of MAC address, a frame transmitted can exactly be received by the target an interface the destination MAC points to.

Amulticast address is identified with a group of network devices or network interfaces. In Ethernet, a many-to-many connectivity in the LANs is provided. It provides a mean to send a frame to many network devices at a time. When all bit of DA is 1s, it is a broadcast, which means all network device except the sender itself can receive the frame and response.

Ethernet Frame Format

There are two major forms of Ethernet frame, type encapsulation and length encapsulation, both of which are categorized as four frame formats 802.3/802.2 SNAP, 802.3/802.2, Ethernet II and Netware 802.3 RAW. We will introduce the basic Ethernet frame format defined by the IEEE 802.3 standard required for all MAC implementations. It contains seven fields explained below.

PRE

SFD

DA

SA

Type/Length

Data Pad bit if any

FCS

7

7

6

6

2

46-1500

4

Fig. 3-3 Ethernet frame structure

-Preamble (PRE) —The PRE is 7-byte long with alternating pattern of ones and zeros used to tell the receiving node that a frame is coming, and to synchronize the physical receiver with the incoming bit stream. The preamble pattern is:

10101010 10101010 10101010 10101010 10101010 10101010 10101010

Start-of-frame delimiter (SFD) — The SFD is one-byte long with

alternating pattern of ones and zeros, ending with two consecutive 1-bits. It immediately follows the preamble and uses the last two consecutive 1s bit to indicate that the next bit is the start of the data packet and the left-most bit in the left-most byte of the destination address. The SFD pattern is 10101011.

Publication date: January, 2005

Revision A1

27

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Edimax Technology ES-516G+ user manual Fcs, Start-of-frame delimiter SFD The SFD is one-byte long with
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ES-516G+ specifications

Edimax Technology has carved a niche for itself in the realm of networking devices, and one of its standout products is the Edimax ES-516G+. This 16-port Ethernet switch is designed to meet the demanding needs of small to medium-sized businesses and network enthusiasts.

At the core of the ES-516G+ is its capacity to support 10/100/1000 Mbps speeds across its 16 ports, enabling efficient data transmission and minimal latency for connected devices. This switch is a Layer 2 unmanaged switch, which simplifies the user experience by eliminating the need for complex configurations. Users can plug in their devices and start functioning immediately, making it an ideal option for those who may not have extensive networking knowledge.

One of the key features of the Edimax ES-516G+ is its support for Auto-MDI/MDI-X, which automatically detects the type of connection required for each port, whether it’s connecting to another switch or end devices like computers and printers. This eliminates the hassle of crossover cables and ensures seamless connectivity.

Moreover, the ES-516G+ incorporates advanced energy-saving technologies that are designed to minimize power consumption without compromising performance. This feature is particularly appealing for environmentally-conscious businesses looking to reduce their carbon footprint. It includes capabilities such as energy-efficient Ethernet (EEE), which adjusts power usage based on the link status and length of connected cables.

The switch features a compact metal housing, providing durability and a professional look suitable for any office environment. It also supports a fanless design for quiet operation, making it an excellent addition to workplaces where noise levels need to be kept to a minimum.

In terms of performance, the Edimax ES-516G+ employs store-and-forward switching technology, which helps to minimize errors by ensuring that only error-free packets are forwarded. This significantly enhances network performance and reliability.

Overall, the Edimax Technology ES-516G+ stands out as a robust, efficient, and user-friendly solution for enhancing network performance in small to medium-sized businesses. Its combination of speed, plug-and-play convenience, energy-saving features, and reliability makes it a compelling choice for users seeking to expand their network capabilities. Whether for a bustling office or a home network, the ES-516G+ is engineered to deliver a seamless, high-performance networking experience.
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