OptiX RTN 950 Radio Transmission System Commissioning Guide (U2000)

two rate three colormarker

The trTCM meters an IP packet stream and marks its packets based on two rates, Peak Information Rate (PIR) and Committed Information Rate (CIR), and their associated burst sizes to be either green, yellow, or red. A packet is marked red if it exceeds thePIR. Otherwise it is marked either yellow or green depending on whether it exceeds or doesn't exceed the CIR.

B.6 U-Z

This section provides the terms starting with letters U to Z.

U-VLAN

A VLAN attribute indicating that the current VLAN is a user VLAN of an M-VLAN.Multicast services are copied from the M-VLAN to the user VLAN.

UAS

unavailable second

UBR

See

unspecified bit rateUDP

See

User Datagram Protocolunderfloor cabling

The cables connected cabinets and other devices are routed underfloor.

UNI

See

user network interfaceunicast

The process of sending data from a source to a single recipient.

unspecified bit rate

No commitment to transmission. No feedback to congestion. This type of service is idealfor the transmission of IP datagrams. In case of congestion, UBR cells are discarded,and no feedback or request for slowing down the data rate is delivered to the sender.

upload

An operation to report some or all configuration data of an NE to the NMS(Network Management system). The configuration data then covers the configuration data storedat the NMS side.

User DatagramProtocol

A TCP/IP standard protocol that allows an application program on one device to send adatagram to an application program on another. User Datagram Protocol (UDP) uses IPto deliver datagrams. UDP provides application programs with the unreliableconnectionless packet delivery service. Therefore, UDP messages can be lost, duplicated,delayed, or delivered out of order. UDP is used to try to transmit the data packet, that is,the destination device does not actively confirm whether the correct data packet isreceived.

user network interface

The interface between user equipment and private or public network equipment (for example, ATM switches).

V-UNI

See

virtual user-network interfacevariable bit rate

One of the traffic classes used by ATM (Asynchronous Transfer Mode). Unlike a permanent CBR (Constant Bit Rate) channel, a VBR data stream varies in bandwidthand is better suited to non real time transfers than to real-time streams such as voice calls.

VBR

See

variable bit rateVC

See

virtual container

VCC

See

virtual channel connectionVCG

See

virtual concatenation groupVCI

See

virtual channel identifierVCTRUNK

A virtual concatenation group applied in data service mapping, also called the internal port of a data service processing board

virtual channelconnection

The VC logical trail that carries data between two end points in an ATM network. Alogical grouping of multiple virtual channel connections into one virtual connection.

virtual channelidentifier

A 16-bit field in the header of an ATM cell. The VCI, together with the VPI, is used toidentify the next destination of a cell as it passes through a series of ATM switches onits way to its destination.

virtual concatenationgroup

A group of co-located member trail termination functions that are connected to the samevirtual concatenation link

virtual container

The information structure used to support path layer connections in the SDH. It consistsof information payload and path Overhead (POH) information fields organized in a block frame structure which repeats every 125 or 500 μs.

virtual local areanetwork

A logical grouping of two or more nodes which are not necessarily on the same physicalnetwork segment but which share the same IP network number. This is often associatedwith switched Ethernet.

virtual path identifier

The field in the Asynchronous Transfer Mode (ATM) cell header that identifies to whichvirtual path the cell belongs.

virtual private LANservice

A type of point-to-multipoint L2VPN service provided over the public network. VPLSenables geographically isolated user sites to communicate with each other through theMAN/WAN as if they are on the same LAN.

virtual private network

A system configuration, where the subscriber is able to build a private network viaconnections to different network switches that may include private network capabilities.

virtual route forward

VRF performs the function of establishing multiple virtual routing devices on one actualrouting device. That is, the L3 interfaces of the device are distributed to different VRFs, performing the function of establishing multiple virtual route forwarding instances onthe device.

virtual user-network interface

A virtual user-network interface, works as an action point to perform serviceclassification and traffic control in HQoS.

VLAN

See

virtual local area network voice over IP

An IP telephony term for a set of facilities used to manage the delivery of voiceinformation over the Internet. VoIP involves sending voice information in a digital formin discrete packets rather than by using the traditional circuit-committed protocols of the public switched telephone network (PSTN).

VoIP

See

voice over IPVPI

See

virtual path identifierVPLS

See

virtual private LAN serviceVPN

See

virtual private network VRF

See

virtual route forward

wait to restore

The number of minutes to wait before services are switched back to the working line.

WAN

See

wide area network Web LCT

The local maintenance terminal of a transport network, which is located on the NEmanagement layer of the transport network

weighted fair queuing

A fair queue scheduling algorithm based on bandwidth allocation weights. Thisscheduling algorithm allocates the total bandwidth of an interface to queues, accordingto their weights and schedules the queues cyclically. In this manner, packets of all priorityqueues can be scheduled.

weighted random earlydetection

A packet loss algorithm used for congestion avoidance. It can prevent the global TCPsynchronization caused by traditional tail-drop. WRED is favorable for the high-priority packet when calculating the packet loss ratio.

weighted round Robin

N/A

WFQ

See

weighted fair queuingwide area network

A network composed of computers which are far away from each other which are physically connected through specific protocols. WAN covers a broad area, such as a province, a state or even a country.

winding pipe

A tool for fiber routing, which acts as the corrugated pipe.

WRED

See

weighted random early detectionWRR

See

weighted round RobinWTR

See

wait to restore

XPIC

See

cross polarization interference cancellation