Black Box Explains...High-speed networking.
What are my choices for high-speed
... more/see it nownetworking?
| 100BASE-T | ATM
| Gibabit Ethernet
Switched Ethernet relies on centralized multiport switches
to provide a physical link between multiple LAN segments.
Inside each intelligent switch, high-speed circuitry supports
wire-speed virtual connections between all the segments
for maximum bandwidth allocation on demand. Adding new segments
to a switch increases the aggregate network speed while
reducing overall congestion, so Switched Ethernet provides
superior configuration flexibility. It also gives you an
excellent migration path from 10- to 100-Mbps Ethernet,
since both segments can often operate via the same switch.
Benefits of Switched Ethernet—It’s
a cost-effective technique for increasing the overall network
throughput and reducing congestion on a 10-Mbps network.
Other than the addition of the switching hub, the Ethernet
network remains the same—the same network interface
cards, the same client software, the same LAN cabling.
100BASE-T retains the familiar CSMA/CD media access technique
used in 10-Mbps Ethernet networks. It also supports a broad
range of cabling options: two standards for twisted pair
and one for fiber. 100BASE-TX supports 2-pair Category 5
UTP or Type 1 STP cable. 100BASE-FX enables fiber optic
links via duplex multimode fiber cable.
Benefits of 100BASE-T—It
retains CSMA/CD, so existing network management systems
don’t need to be rewritten. It can easily be integrated
into existing 10-Mbps Ethernet LANs, so your previous investment
is saved (see Figures 1 and 2).
It’s also backed by hundreds of manufacturers in the
high-speed networking industry, including Black Box!
||100BASE-T (IEEE 802.3u)
of this Standard
||Category 5 (2-Pair)
||Duplex Multimode or Single-Mode
|| Category 5—100
||Backbone using Ethernet
switches to provide increased throughput. Small to medium
workgroups using applications (i.e. CAD, CAM) that output
huge data files.
Asynchronous Transfer Mode (ATM) is a cell-based fast-packet
communication technique that supports data-transfer rates
ranging from sub-T1 speeds (less than 1.544 Mbps) up to
Like other packet-switching services (Frame Relay, SMDS),
ATM achieves its high speeds in part by transmitting data
in fixed-size cells and dispensing with error-correction
protocols. Instead, it relies on the inherent integrity
of digital lines to ensure data integrity.
Benefits of ATM—Networks
are extremely versatile. An ATM network can be treated as
a single network, whether it connects points in a building
or across the country. Its fixed-length cell-relay operation,
the signaling technology of the future, offers more predictable
performance than variable-length frames. And it can be integrated
into an existing network as needed without having to upgrade
the entire LAN.
Like Ethernet and Fast Ethernet before it, Gigabit Ethernet
works with earlier versions of the IEEE 802.3 standard—both
10 and 100 Mbps— although some equipment will need
to be upgraded. The Gigabit Ethernet standard (IEEE 802.3z)
was approved in June 1998, and its speed of 1 Gbps is a
tenfold increase over Fast Ethernet.
There are two basic types of Gigabit Ethernet: shared
and switched. Shared Gigabit Ethernet
is a higher-speed version of 10/100BASE-T using CSMA/CD
Medium Access Control. Switched Gigabit Ethernet uses Logical
Link Control (LLC). Gigabit Ethernet increases frame sizes
from 64 bytes to 512 bytes minimum, and from 1514 bytes
to 9000 bytes maximum.
Benefits of Gigabit Ethernet—It
solves bandwidth problems. Its primary use is for backbones.
The medium is fiber or Category 5e 100-ohm cable. collapse
PoE+ Gigabit Managed Switch Eco User Manual
User Manual for the LPB2810A, LPB2826A, and LPB2848A (Version 1)
Product Data Sheets (pdf)...Express Ethernet Switches
Product Data Sheets (pdf)...PoE L2 Managed 10/100 Switch with (2) Dual-Media SFP Ports
Product Data Sheets (pdf)...L2 Managed Gigabit Ethernet Switches with Dual-Media SFP Ports WebSmart Gigabit Switches
Product Data Sheets (pdf)...PoE PD Switches
- Quick Start Guide...
PoE+ Gigabit Managed Switch Eco Quick Start Guide (QSG)
Quick Start Guide for the LPB2810A, LPB2826A, and LPB2848A (Version 1)
26-Port Gigabit Managed Switch Firmware
Firmware for the LGB1126A (Version v2.00)
Black Box Explains...Power over Ethernet (PoE).
Product Data Sheets (pdf)...Back Office Switches
What is PoE?
The seemingly universal network connection, twisted-pair Ethernet cable, has another role to play, providing electrical power to low-wattage electrical devices. Power over Ethernet (PoE) was ratified by the... more/see it nowInstitute of Electrical and Electronic Engineers (IEEE) in June 2000 as the 802.3af-2003 standard. It defines the specifications for low-level power delivery—roughly 13 watts at 48 VDC—over twisted-pair Ethernet cable to PoE-enabled devices such as IP telephones, wireless access points, Web cameras, and audio speakers.
Recently, the basic 802.3af standard was joined by the IEEE 802.3at PoE standard (also called PoE+ or PoE plus), ratified on September 11, 2009, which supplies up to 25 watts to larger, more power-hungry devices. 802.3at is backwards compatible with 802.3af.
How does PoE work?
The way it works is simple. Ethernet cable that meets CAT5 (or better) standards consists of four twisted pairs of cable, and PoE sends power over these pairs to PoE-enabled devices. In one method, two wire pairs are used to transmit data, and the remaining two pairs are used for power. In the other method, power and data are sent over the same pair.
When the same pair is used for both power and data, the power and data transmissions don’t interfere with each other. Because electricity and data function at opposite ends of the frequency spectrum, they can travel over the same cable. Electricity has a low frequency of 60 Hz or less, and data transmissions have frequencies that can range from 10 million to 100 million Hz.
There are two types of devices involved in PoE configurations: Power Sourcing Equipment (PSE) and Powered Devices (PD).
PSEs, which include end-span and mid-span devices, provide power to PDs over the Ethernet cable. An end-span device is often a PoE-enabled network switch that’s designed to supply power directly to the cable from each port. The setup would look something like this:
End-span device → Ethernet with power
A mid-span device is inserted between a non-PoE device and the network, and it supplies power from that juncture. Here is a rough schematic of that setup:
Non-PoE switch → Ethernet without PoE → Mid-span device → Ethernet with power
Power injectors, a third type of PSE, supply power to a specific point on the network while the other network segments remain without power.
PDs are pieces of equipment like surveillance cameras, sensors, wireless access points, and any other devices that operate on PoE.
PoE applications and benefits.
• Use one set of twisted-pair wires for both data and low-wattage appliances.
• In addition to the applications noted above, PoE also works well for video surveillance, building management, retail video kiosks, smart signs, vending machines, and retail point-of-information systems.
• Save money by eliminating the need to run electrical wiring.
• Easily move an appliance with minimal disruption.
• If your LAN is protected from power failure by a UPS, the PoE devices connected to your LAN are also protected from power failure.