(Note: The following definitions were compiled from PC Mag.com, webopedia.com, belevurlinux.org, searchnetworking.com, techtarget.com, secure.enterasys.com, wikipedia, Newton’s Telecom Dictionary, and VERSITRON manuals, unless otherwise marked.)
| Aging Time |
Begins when an address is learned and resets whenever a frame arrives at a port. When aging time expires, the address and port are discarded. |
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| Algorithm |
Finite list of well-defined instructions for accomplishing some task that given an initial state, will terminate in a defined end-state. |
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| Auto MDI/MDI-X Detection |
Auto-MDI (Medium Dependent Interface)/MDIX (MDI crossover) is an ethernet port feature that automatically adjusts to crossover or straight-through ethernet cable so you can use either to connect your device to a computer or a switch/external hub. (Zyxel.com) |
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| Auto-Negotiation |
A mechanism that takes control of the cable when a connection is established to a network device. Auto-negotiation detects the various modes that exist in the device on the other end of the wire and advertises its own abilities to automatically configure the highest performance mode of interoperation. As a standard technology, this allows simple, automatic connection of devices that support a variety of modes from a variety of manufacturers. (An Introduction to Auto-Negotiation, Bill Bunch) |
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| Auto-Sensing |
Auto-sensing involves probing the capability of the network using low-level signaling techniques to select compatible ethernet speeds. Auto Sensing was developed to make the migration from traditional ethernet to fast ethernet products easier. When first connected, 10/100 devices automatically exchange information with each other to agree on a common speed setting. (about.com) |
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| Bandwidth |
The amount of data that can be carried from one point to another in a given time period (usually a second). Expressed in bit (of data) per second (bps) or occasionally bytes per second (bps). A modem that works at 57,600 bps has twice the bandwidth of a modem that works at 28,800 bps.
(networking.com) |
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| Broadcast Packet |
On ethernet, a broadcast packet is a special type of multicast packet which all nodes on the network are always willing to receive. (Die.net) |
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| Buffer Memory |
Is a portion of a computer’s memory that is set aside as a temporary holding place for data that is being sent to or received from an external device, such as a hard disk (HDD), keyboard or printer. A buffer in a computer system is usually located between two devices that have different speeds for handling data or used when there is a difference in the timing of events. It is analogous to a reservoir, which captures water upstream and then lets it out at controlled speeds intended to prevent the lower river from overflowing its banks. Likewise, a buffer in a computer ensures that data has somewhere to go i.e. into the buffer temporarily until its ultimate destination becomes available.
(from bellevuelinux.org) |
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| CLI |
Command Line Interface -a user interface to an application that accepts typed-in commands a line at a time. |
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| dBm |
A measure of power loss in decibels using 1 milliwatt as the reference point. A signal received at 1 milliwatt yields 0 dBm. A signal at .1 milliwatt is a loss of 10 dBm. A unit of measurement of the loudness or strength of a signal. One decibel is considered the smallest difference in sound level that the human ear can discern. Decibels are a relative measurement derived from two signal levels: a reference input level and an observed output level. A decibel is the logarithm of the ratio of the two levels. |
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| Double Tag Capability |
Addition of an extra VLAN tag. Used to manage traffic in a MAN without affecting properties in surrounding LANs. |
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| Duplex |
Both ends of the communication can send and receive signals at the same time. |
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| Egress Port |
The output port from which a packet is sent out. |
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| Egress Rules |
A device determines which frames can be transmitted out of a port based on the Egress List of the VLAN associated with it. Each VLAN has an Egress List that specifies the ports out of which frames can be forwarded, and specifies whether the frames will be transmitted as tagged or untagged frames. You can add or remove ports to or from a VLAN’s egress List, thereby controlling which VLAN’s frames can be forwarded out which ports. |
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| FEFI |
Far End Fault Indication – function that will bring the link down on both sides. |
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| Fiber Uplink |
Data transmission from a data station to the headend or mainframe over fiber. |
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| Filtering |
The process of selecting which traffic will be allowed into a certain portion of a network, such as the wide area network. It is also the process of determining which traffic is transmitted first, then next, and so on. The traffic is compared to a filter, or a set of specifications to determine if it can pass through or not. |
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| Firmware |
Software kept in semi-permanent memory. Firmware is used in conjunction with hardware and software. It also shares the characteristics of both. Firmware contains software which is so constantly called upon by a computer or phone system that it is “burned” into a chip, thereby becoming firmware. Firmware is non-volatile. It will not be “forgotten” when the power is shut off. |
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| Flash |
Quickly depressing and releasing the plunger to create a signal to a PBX or Centrex that special instructions will follow. |
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| Flash Memory |
Non-volatile storage – storage that can retain information without electricity, but
which can be electrically erased and reprogrammed. Flash memory occupies little space and doesn’t need continuous power to retain its memory. |
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| Forwarding |
The act of forwarding a network port from one network node to another. This technique can allow an external user to reach a port on a private IP address (inside a LAN) from the outside via a NAT-enable router. Port forwarding allows remote computers (e.g. public machines on the Internet) to connect to a specific computer within a private LAN. |
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| Flow Control |
The hardware, software and procedure for controlling the transfer of messages or characters between 2 points in a data network—such as between a protocol converter and a printer—to prevent loss of data when the receiving device’s buffer begins to reach its capacity. In flow control, you can also deny access to additional traffic that would further add to congestion. (Newton’s Telecom Dictionary) |
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| FX Port |
The optical fiber port of the media converter device. |
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| GBIC module |
Gigabit Interface Connector. The physical connection to Gigabit Ethernet media. A removable optical interface transceiver module designed to carry gigabit ethernet or fiber channel traffic. |
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| Gigabit Uplinks |
Data transmission from a data station to the headend or mainframe at 1000 megabits per second. |
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| Ingress Port |
The input port on which a packet is received. |
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| Ingress Rules |
A device determines which frames can be transmitted out a port based on the Egress list of the VLAN associated with it. Each VLAN has an Egress List that specifies the ports out of which frames can be forwarded, and specifies whether the frames will be transmitted as tagged or untagged frames. You can add or remove ports to or from a VLAN’s Egress List, thereby controlling which VLAN’s frames can be forwarded out which ports. (Determines which frames can be transmitted out of a port.)
When a frame is transmitted out of a port, the device first checks the Egress List. If the port is listed on the Egress List of the VLAN associated with it, the frame is then transmitted according to the priority assigned to the frame. The frame is transmited as tagged or untagged according to the specification in the Egress List. If the port is not on the Egress List, or if the port is not operational, the frame is discarded. (secure.enterasys.com) |
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| IP TOS Classification |
Enables you to define a class of service that prioritizes traffic with an 802.1p priority (with or without rate limiting) and, if desired, an IP TOS (Type of Service) or DSCP (Diffserv Codepoint) value. You can then assign the class of service as a classification rule action, as part of the definition of an automated service, or as a role default. (secure.enterasys.com) |
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| IP DiffServ Classification |
A computer networking architecture that specifies a simple, scalable, and coarse-grained mechanism for classifying, managing network traffic and providing quality of service guarantees on modern IP networks. DiffServ can, for example, be used to provide low latency, guaranteed service (GS) to critical network traffic such as voice or video while providing simple best effort traffic guarantees to non-critical services such web traffic or file transfers. (wikipedia) |
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| IGMP |
Internet Group Management Protocol. A protocol used by IP hosts and gateways to report their multicast group memberships. When used in concert with a multicast protocol, the IP-based network can support multicasting. |
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| IGMP Snooping Capability |
A layer-2 switch listens or snoops the layer 3 IGMP traffic to determine which ports receive multicast traffic. IGMP snooping can be configured on a per VLAN basis. Traffic will only be forwarded to thos ports that want to receive the multicast transmission. (advanced comms.agilent.com) |
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| Internal Routing |
Defines the route to the destination queue. |
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| Link Fault Pass-Through Function |
This feature can force the link to shut down as soon as it notices the other link has failed. It allows a link partner on one cable segment to notice that a link fault has occurred on another
segment. |
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| Loop Back Test |
A connection from the server back to itself. |
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| Loop Back Test Function |
Verifies the fiber link with its link partner by sending test packets to the link partner and verifying the echo packets sent back. Helpful in checking the connection quality of the fiber link during installation. |
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| LED |
Light emitting diode. A semi-conductor diode which emits light when a current is passed throughit, the intensity of the light varying with the amount of current. |
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| Multimode Fiber |
A fiber optic cable with a wide core that provides multiple routes for light waves to travel. Its wider diameter of between 25 to 200 microns prevents multimode fiber from carrying signals as far as single-mode fiber due to modol dispersion. |
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| MDI |
Medium Dependent Interface. An ethernet port connection that allows network hubs or
switches to connect to other hubs or switches without a null-modem, or crossover, cable.
(webopedia) |
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| MDI-X |
Medium Dependent Interface Crossover ( the “X” representing “crossover”), an ethernet port
connection that allows networked end stations (i.e. PCs or workstations) to connect to each
other using a null-modem, or crossover, cable. (webopedia) |
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| MAC Address Table |
In a local area network (LAN) or other network, the MAC (Media Access Control) address is your computer’s unique hardware number. (On an ethernet LAN, it’s the same as your ethernet address.) When you’re connected to the internet from your computer (or host as the internet porotocol thinks of it), a correspondence table relates your IP address to your computer’s physical (MAC) address on the LAN. (searchnetworking.techtarget.com) |
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| Metro-LAN |
A network covering an area larger than a local area network, but less than a wide area network. (WAN) |
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| Multi-Casting |
The ability of one network node to send identical data to a number of end point updates known as broadcast in other circles; one example is if new software or addressing updates need to be distributed to all users; also, a point to multipoint video transmission is a multi-cast operation. |
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| nm |
Nanometer – one billionth of a meter. Unit for describing the wavelength of light. |
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| Network node (NN) |
A grouping of one or more network elements (at one or more sites) which provides network related functions, and is administered as a single entity. A single site may contain more than one network node. (wikipedia) |
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| NTSC |
The National Television System Committee was established in 1940 by the Federal Communications Commission (FCC), in the United States (US), to resolve the conflicts which
had arisen between companies over the introduction of a nationwide analog television system
in the U.S. (for setting television and video standards in the United States.) |
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| Packet Filtering |
The recognition and selective transmission of blocking of individual packets based on destination addresses or other packet contents. Packet filtering can accept or reject packets based on pre-defined rules. This ability helps to control network traffic. |
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| PAL |
Phase Alternating Line is a color encoding system used in broadcast television systems in many parts of the world. |
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| Port |
Is generally a specific place for being physically connected to some other device, usually with a
socket and plug of some kind. |
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| Port (2) |
Is a special number present in the header of a data packet. Ports are typically used to map
data to a particular process running on a computer.
Ports can be readily explained with an analogy: think of IP addresses as the street address of a block of flats (apartment complex), and the port number as the number of a particular flat
(apartment) within that building. If a letter (a data packet) is sent to the flats (IP) without a
flat number (port number) on it then nobody knows who it is for (which service it is for).
In order for the delivery to work, the sender needs to include a flat number (apartment number)along with the address to ensure the letter gets to the right domicile. (wikepedia) |
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| Port Link Aggregation |
The grouping of multiple network links into one logical high bandwidth link. Ex. You can group four separate leased T-1 links, each offering bandwidth of 1.544 Mbps, into a single logical link offering aggregate bandwidth of 6 Mbps. |
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| Port bandwidth Control Function |
Manages endpoint bandwidth requirements. |
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| Port Mirroring |
Is used on a network switch to send a copy of all network packets seen on one switch
port to a network monitoring connection on another switch port. This is commonly used for network appliances that require monitoring of network traffic, such as intrusion detection system. (wikepedia) |
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| Port PVID |
This setting value is used for VLAN group lookup index. Each port has a default VID--voltage indentification called PVID. When an untagged frame is received, Ingress Process inserts a tag containing the PVID into the untagged frame. PVID is assigned to untagged frames or priority tagged frames so they may go on to the forwarding process. (zyxel.com) |
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| Port Security |
Technology that allows you to automate the process of checking hardware that is connecting to your corporate network. In its crudest form, if a box does not meet the minimum policy requirements, it is not allowed onto the network. In its more sophisticated incarnations, port security pushes the offending hardware over to a limited access virtual LAN where it can pick up the required security tools before being allowed to join the corporate network. (searchsecurity.techtarget.com – Scott Sidel) |
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| Port Tag Mode |
Setting for each port to be a tagged port or untagged port for outbound. |
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| Port Trunking |
trunking is a special function that can be assigned to a port, making that port capable of carrying traffic for any or all of the VLANs accessible by a particular switch. Such a port is called a trunk port, in contrast to an access port, which carries traffic only to and from the specific VLAN assigned to it. A trunk port marks frames with special identifying tags (either ISL tags or 802.1Q tags) as they pass between switches, so each frame can be routed to its intended VLAN. (search networking.com) |
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| Q-in-Q Application |
VLAN stacking |
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| QoS |
Quality of Service – For conversion between 2 different speeds, QoS classifies the priority
for received network frames based on ingress port and frame contents. When congestion happens on some ports of the switch, the QoS operation can transfer packets with different priorities, different drop rates, different bandwidth allocations for different requests of packets. |
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| RAM Buffers |
A part of Random Access Memory used for temporary storage of data that is waiting to be
sent to a device; used to compensate for differences in the rate of flow of data between components of a computer system. |
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| Remote TP Port Status Monitoring |
When 2 devices are connected with each other via fiber link, the device can monitor and display the twisted pair port status of the remote fiber link partner. The status display can be on the local LED indicators or web-management interface. |
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| RMON agent |
Remote Monitoring Specification – A simple network management protocol used to manage networks remotely. It provides multi-vendor interoperability between monitoring devices and management stations, (Newton’s Telecom Dictionary) |
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| SECAM |
Sequential Color with Memory – is an analog color television system first used in France and
the first European color television standard. |
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| Self-Learning |
Self-learning bridges “learn” the addresses of the attached devices on each segment by
initiating broadcast query packets, and then remembering the originating addresses of the
devices which respond. Self-learning bridges perform this process at regular intervals in
order to repeat the “learning” process and, thereby, to adjust to the physical relocation of
devices, the replacement of NICs (Network Interface cards), and other changes in the dynamic LAN environment. |
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| Singlemode Fiber |
Fiber optic cable in which the signal or light propagates in a single mode or path.
Since all light follows the same path or travels the same distance, a transmitted pulse is not dispersed and does not interfere with adjacent pulses. Can support longer distances. (Newton’s Telecom) |
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| SNMP |
Simple Network Management Protocol, a set of protocols for managing complex networks.
SNMP works by sending messages, called protocol data units (PDUs), to different parts of
a network. SNMP-compliant devices, called agents, store data about themselves in
Management information bases (MIBs) and return this data to the SNMP requesters.
(webopedia) |
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| Spanning Tree |
An algorithm used to prevent logic loops in a bridged network by creating a spanning
tree. When multiple paths exits, STA lets a bridge use only the most efficient one. If that path fails, STA automatically reconfigures the network to make another path become active, sustaining network operations. (Newton’s Telecom) |
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| Store and Forward Architecture |
A message is transmitted to some intermediate relay point and stored temporarily. Later the message is sent the rest of the way. Useful for one-way transmission of messages. |
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| TP Port |
The twisted-pair copper port of the media converter device. |
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| Trap |
A message that reports a problem or significant event (et.put.poznan.pl) |
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| Trap Function |
Allows the device to send the trap message to an SNMP trap host over SNMP protocol
when the associated trap event occurs. |
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| Trap Settings |
Used to configure a trap host who can receive the SNMP trap message issued from a media converter device unit. |
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| Untagged packet |
A standard ethernet frame with no VLAN tag field. |
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| VLAN |
Virtual Local Area Network. A VLAN is a switched network in a collection of devices grouped
together to form a virtual network within a larger network. VLANs allow an administrator to
create networks based on parameters beyond the network address, hence the name “virtual”.
The virtual aspect of VLANs refers to the fact that devices in a VLAN behave as though they
are on the same wire, even though they may be physically located on different segments of the
LAN. In fact, a VLAN can even extend across a WAN, a wide area network. The reason to
create a VLAN is to segment a large subnet. This simplifies user mobility and provides
broadcast controls. |
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| VLAN-Tagged Packet |
An IEEE 802.1Q packet which VIC field value is not zero. |
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| VSM |
Virtual Systems Management – Virtual systems management (VSM), also known as virtual
system management, is the process of remotely managing the allocation and use of resources in conventional networks as well as in virtual area networks, virtual private networks, virtual
network computing, and virtual servers. In VSM, resources are distributed to minimize the risk of catastrophic system failure and to streamline the process of disaster recovery in the event of
a major system compromise. In addition, VSM can minimize problems that commonly occur with the use of multiple operating systems and can optimize the effectiveness with which resources are shared. (searchnetworking.com) |
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| Web-Based Management |
The device is embedded with an Http server which provides management functions for advanced network functions including Port Control, Quality of service, and Virtual LAN functions. The management can be performed via web browser interface over TCP/IP network. |
