Page 11 - 2015 Master Catalog
P. 11

Network Time Protocol (NTP)

The Network Time Protocol (NTP) is a protocol for synchronizing all of the clocks in a network, using a set of
distributed clients and servers.

Port Trunking and Link Aggregation Control Protocol (LACP, IEEE802.3ad)

Trunking is also called link aggregation, which serves as a shortcut to increase the bandwidth on a network.
Trunking is a method of physically linking several ports together to act as a single port with higher bandwidth.
This functionality allows bandwidth scaling. In addition, the trunking algorithm provides dynamic fail-over.
Traffic automatically gets distributed to the remaining active ports if one of the ports fails, allowing for a
seamless method of redundancy to occur over a trunk.

Port Security

EtherWAN's Managed Ethernet Switches provide filtering for source and destination MAC addresses. MAC
address filtering allows a managed Ethernet switch to block an incoming packet to an interface when it sees
a specified MAC address in either the source address or the destination address of the incoming packet. This
filters unnecessary traffic, thereby providing intelligent control over traffic flows and broadcast traffic.

Port Mirroring

Port mirroring allows packets to be mirrored for network monitoring purposes and network debugging
purposes. Traffic from any port can be mirrored to any other port using port mirroring.

PoE (Power over Ethernet)

Power over Ethernet or PoE technology describes a system of safely passing electrical power, along with data,
through Ethernet cabling. The IEEE standard for PoE requires category 5 cable or higher for high power levels,
but it can operate with category 3 cable for low power levels. Power is supplied in common mode over two or
more of the differential pairs of wires found inside an Ethernet cable. It can come from a power supply within
a PoE-enabled networking device, such as an Ethernet switch, or it can be injected into a cable that has a
midspan power supply.

The original IEEE 802.3af-2003 PoE standard provides up to 15.4 W of DC power (a minimum of 44 VDC and
350 mA) to each device. However, only 12.95 W is certain to be available at the powered device, as some
power will be dissipated in the cable. The updated IEEE 802.3at-2009 PoE standard, also known as PoE+ or PoE
plus, provides up to 25.5 W of power. The 2009 standard prohibits a powered device from using all four pairs
of wire for power; however, some vendors have announced products that claim to be compatible with the
802.3at standard and that can offer up to 51 W of power over a single cable, by utilizing all four pairs of wire in
a category 5 cable.

Ethernet Switch Glossary  10  www.EtherWAN.com
   6   7   8   9   10   11   12   13   14   15   16