Quality and Availability Calculations Flashcards
Network performance objectives for IP-Based Services (2002)
ITU-T Recommendation Y.1541
______ are assumed to cause relatively slow-fading events, contributing to unavailable time.
Rain and refraction-diffraction fading
_____ defines parameters that may be used in specifying and assessing the speed, accuracy, dependability, and availability of IP packet transfer of international IP data communication services.
ITU-T Recommendation Y.1540
Multipath fading (flat and selective) is assumed to cause _______, affecting the quality of the link.
Fast-fading event
The ratio of ES to total seconds in available time during a fixed measurement interval.
Error second ratio (ESR)
Three types of Hardware Redundancy
Hot-Standby Protection
Multichannel Protection
Multiline Protection
Quality parameters defined by ____ and applied by ____ are BER based.
ITU-T Recommendation G.821
ITU-R Recommendations
Performance Objectives and Procedures for Provisioning and Maintenance of IP-based Networks (2002)
ITU-T Recommendation M.2301
A 1-sec period that contains over 30 percent errored blocks or at least one defect. SES is a subset of ES.
Severely errored second (SES)
____ is a set of consecutive bits associated with the path; each bit belongs to one and only one block.
Block
Five types of Diversity Techniques
Frequency Diversity
Space Diversity
Hybrid Diversity
Route Diversity
Media Diversity
A _____ as defined by ITU-T Recommendation G.826 is the whole means of digital transmission of digital signal of a specified rate, including the path overhead (where it exists) between equipment at which the signal originates and terminates.
Hypothetical reference path (HRP)
IP Data Communication Service - IP Packet transfer and Availability Performance Parametes (2002)
ITU-T Recommendation Y.1540
In digital transmission technology, any bit received in error a ______ may deteriorate with an increasing number of erroneous bits.
bit error
The main purpose of the ____ is to set up reasonable objectives for the microwave path.
Quality and Availability Calculations
ITU-T Recommendation G.828 only applies to:
Synchronous Digital Hierarchy (SDH) Systems.
An end to end HRP spans a distance of _____.
27, 000 km
The ratio of SES to total seconds in available time during a fixed measurement interval.
Severely errored second ratio (SESR)
Frequency range between ____ and ____ where both quality and availability might be comparable and all the mechanisms have to be considered.
10 and 15 GHz
The quality will decrease with an ______ number of erroneous bits.
Increase
Unavailability due to radio wave propagation (rain and refraction-diffraction fading) can be strongly length dependent).
True
An errored block not occurring as part of an SES.
Background block error (BBE)
It should be noted that ITU-T Recommendation G.828 only applies to equipment designed after _______.
March 10, 2000
A block in which one or more bits are in error.
Errored block (EB)
ITU-T Recommendation G.826 applies to both:
Plesiochronous Digital Hierarchy (PDH)
Synchronous Digital Hierarchy (SDH)
______ are processed in a similar way as bit errors.
Block errors
Unavailability due to hardware failure is, obviously, not path-length related.
True
In-service detection of errors in digital transmission is possible through special error detection mechanisms which are inherent to certain transmission systems such as ____, _____, and observation of _____.
Cyclic redundancy check (CRC)
Parity Check
Bit interleaved parity (BIP).
After the completion of the quality and availability calculations, the next step is ____.
Interference Analysis
_____ is capable of detecting whether one or more errors have occurred in a given sequence of bits - the block.
Error detection
The ____ referred to the total number of bits transmitted in a given time interval is a quantity that can be used to describe digital transmission performance.
Ratio of the number of errored bits
The ratio of background block errors (BBE) to total blocks in available time during a fixed measurement interval.
Background block error ratio (BBER)
The quality parameters are ____ and ____.
Errored Second ratio (ESR)
Severely errored Second ratio ( SESR)
_____ is the dominating dimensioning factor for frequencies above 15 GHz
Unavailability
The dominating and dimensioning factor for frequencies below 10 GHz (8Ghz in some countries).
Quality
One of the prime objectives of ___ was to define all performance parameters in such a way that in-service estimation is possible.
G.826
BER measurements are mostly performed out of service using a well-defined _____.
Pseudorandom bit sequence (PRBS)
A 1-sec period with one or more errored blocks at least one defect.
Errored second (ES)
Error performance should be evaluated only during the time the path is in the available state.
True
The availability parameter is ____ or ____.
Available time ratio (ATR) or Unavailable time ratio (UATR)
______ defines six network Quality of services (QoS) and specifies provisional objectives for Internet Protocol Network Performance Parametes.
ITU-T Recommendation Y.1541
The portion of interest is usually the national portion of the HRP subdivided in three classes:
Access, short-haul and long-haul.
______ is defined as the ratio of the number of errored blocks referred to the total number of blocks transmitted in a given time interval.
Block error ratio
The quantity called ____ is a well-known and commonly used error performance parameter.
Bit error ration (BER)
Can be measured only if the bit structure of the evaluated sequence is known.
Bit error ratio
Two ways in improving the microwave system
Hardware Redundancy
Diversity Techniques
______ focuses attention on parameters that significantly affect the quality of service perceived by the customer and the methods of measuring those parameters, including those parameters that affect delay performance at the application layer.
ITU-T Recommendation M.2301
