DWDM, CPAN & OTN Flashcards
WDM system, using the two widely spaced wavelengths in the 1310 nm and 1550 nm (or 850 nm and 1310 nm) is called
1) narrowband WDM
2) wideband WDM
3) DWDM
wideband WDM
WDM system, two to eight channels spaced at an interval of about 400 GHz in the 1550-nm window
1) narrowband WDM
2) wideband WDM
3) DWDM
narrowband WDM
16 to 160 channels and spacing from 25GHz to 200 GHz intervals
1) narrowband WDM
2) wideband WDM
3) DWDM
DWDM
WDM Optical amplifiers boost light waves without converting it into electrical form. (T/F)
T
DWDM infrastructure _______
the distances between network elements
1) increases
2) decreases
3) no change
increases the distances
DWDM systems are _____ and can accept any combination of interface rates
1) bit-rate dependent and format independent
2) bit-rate and format independent
3) bit-rate and format dependent
4) bit-rate dependent and format independent
bit-rate and format independent
Two key elements of WDM optical amplifier
the optical fiber that is doped with
the element erbium and the amplifier
Automatic adjustment of the optical amplifiers when channels are added or
removed achieves optimal system performance. This is because
1) if there is just one channel on the system with high power, degradation in
performance through self-phase modulation can occur.
2) too little power results in not enough gain from the amplifier.
3) both 1 and 2
4) none of the above
both 1 and 2
In the 1530- to 1565-nm range
1) silica-based optical amplifiers perform better
2) fluoride-based optical amplifiers perform better
3) both perform equally well
both perform equally well
Which one is costly
1) silica-based optical amplifiers
2) fluoride-based optical amplifiers
fluoride-based optical amplifiers
to upgrade the WDM channel capacity or wavelengths
1) require more power
2) need additional signal-to-noise margin
3) either 1 or 2
4) none
either 1 or 2
To double the WDM number of channels or the bit rate, __ dB of additional
signal-to-noise margin is needed
1) 1dB
2) 2dB
3) 3dB
4) 4dB
3 dB
The _____ grid is made up of
18 wavelengths defined within the range 1270 nm to 1610 nm spaced by 20 nm
1) BWDM (normal DWM)
2) CWDM
3) DWDM
CWDM
_____ typically uses 20-nm spacing (3000 GHz) of up to 18 channels
1) BWDM (normal DWM)
2) CWDM
3) DWDM
CWDM
________ common spacing may be 200, 100, 50, or 25 GHz with channel count reaching up to 128 or more
1) BWDM (normal DWM)
2) CWDM
3) DWDM
DWDM
second transmission window
1) 850nm
2) 1300nm
3) 1530 to 1565
4) 1565 to 1620
1300nm
third transmission window
1) 850nm
2) 1300nm
3) 1530 to 1565
4) 1565 to 1620
1530 to 1565
fourth transmission window
1) 850nm
2) 1300nm
3) 1530 to 1565
4) 1565 to 1620
1565 to 1620
Conventional Band
1) 850nm
2) 1300nm
3) 1530 to 1565
4) 1565 to 1620
1530 to 1565
Long Band
1) 850nm
2) 1300nm
3) 1530 to 1565
4) 1565 to 1620
1565 to 1620
Technological reasons limit DWDM applications at the moment to the _______ window
1) first and second
2) second and third
2) third and fourth
third and fourth window (conventional band and long band)
most popular optical amplifier is ______
EDFA (Eribium Doped Fiber Amplifier)
EDFA can increase capacity of DWDM (T/F)
T
The _____ carries information about the multi-wavelength optical signal as well as remote conditions at the optical terminal or EDFA site
1) OSC
2) First Wavelength
3) Last wavelength
OSC: optical supervisory channel
3R indicates (in overhead-monitoring multi-bitrate 3R regenerators)
Re-time, Re-transmit, Re-shape
multiplexed transponder is muxponder. (T/F)
T
Enhanced WDM combines CDWDM and DWDM. (T/F)
T
Wavelength conversion is done in _______
1) transceiver
2) transponder
transponder
______combine the benefits of SONET/SDH technology with the bandwidth expandability of DWDM
1) OTN
2) CPAN
3) MPLS
OTN
The newly developed OTN is specified in ITU-T G.____ Network Node Interface for the Optical Transport Network (OTN)
G.709
The ITU-T standards cover the
1) encapsulation format
2) multiplexing, switching
3) management, supervision, and survivability of optical
channels carrying client payloads
4) All of the above
All of the above
OTN also provides the ability
1) to measure network performance across multiple service providers‘ domains
2) to provide seamless, end-to-end monitored services.
3) both above
4) none of the above
both above
ITU Standard G.709 is commonly called 1) OTN
2) SDH
3) SONET
4) CPAN
OTN
_____ sometimes referred to as digital wrapper (DW)
1) DWDM
2) SDH
3) OTN
4) CPAN
??
OTN supports
1) wideband services
2) narrowband services
3) both
4) none
both wideband and narrowband
OTN wrapper provides complete transparency for client signals in ___
1) fixed containers
2) flexible containers
flexible containers
in OTN, there is no contention between concurrent services or users. (T/F)
T
OTN facilitates efficient use of DWDM
capacity by ensuring _______ are maintained across a network using OTN switches at fiber junctions.
1) frame rates
2) fill rates
3) bit rates
fill rates
in OTN using ______ network upgrades can be tested or introduced in a protected network partition or sandbox, without the risk of impacting day-to-day network operations in production partitions
1) O-VLAN
2) O-VPN
3) O-LAN
O-VPN
OTN sandbox environment is formed using
1) O-VLAN
2) O-VPN
3) O-LAN
O-VPN
OTN networks ensure a high level of privacy and security through __________ of traffic onto dedicated circuits
1) soft partitioning
2) hard partitioning
3) mixing
hard partitioning
OTN network management data is carried on a _________
1) same channel as user application data
2) separate channel completely isolated from user application data
3) either 1 or 2
separate channel completely isolated from user application data
OTN has ______the number of bytes
reserved for Forward Error Correction (FEC)
1) kept same
2) decreased
3) increased
increased
OTN has a theoretical improvement of the Signal-to-Noise Ratio (SNR) by ___due to FEC improvement
1) 3dB
2) 6.2dB
3) 5.5dB
4) 2dB
6.2dB
In OTN, Improved SNR helps in
1) increasing span length
2) increasing the number of spans
3) increasing the number of channels
4) All of the above
All of the above
transparent optical network elements which are fundamental for the evolution from point-to-point optical networks to meshed ones
1) OADM
2) OXC
3) both
4) none
both
TCM stands for _______
Tandem Connection Monitoring
______ enables the user and its
signal carriers to monitor the quality of the traffic that is transported between segments or connections in the network.
1) FEC
2) TMN
3) TCM
TCM (Tandem Connection Monitoring)
OTN has fixed _______
1) frame rate
2) frame size
frame size. (SDH has fixed frame rate)
OTN mapping of payloads
1) synchronous
2) asynchronous
asynchronous (SDH has synchronous)
OTN performs _______ multiplexing
1) single-stage
2) multi-stage
single-stage
increases frame size as client
size increases
1) SDH
2) OTN
SDH
increases frame rate as client
rate increases
1) SDH
2) OTN
OTN
OTN FEC sized for error correction to
correct ___ blocks per frame
1) 8
2) 16
3) 32
4) 64
16 blocks
OTN carry services of
1) synchronous
2) asynchronous
3) both
both
OTN includes per-service timing adjustments to carry both
OTN _____ multiplex synchronous and asynchronous services into a common wavelength
1) can
2) cannot
can
In optical transport hierarchy (OTH), The electrical domain is structured in a hierarchical order just like ______
1) SDH multiplexing
2) DWDM multiplexing
SDH multiplexing
In optical transport hierarchy (OTH), The optical domain is structured in a hierarchical order just like ______
1) SDH multiplexing
2) DWDM multiplexing
DWDM multiplexing
OTH ITU recommendation G.872 on
1) architecture
2) frames and formats
3) functions and processes
architecture
OTH ITU recommendation G.709 on
1) architecture
2) frames and formats
3) functions and processes
frames and formats
OTH ITU recommendation G.798 on
1) architecture
2) frames and formats
3) functions and processes
functions and processes
OTH ITU recommendation G.872 on architecture defines classes of interfaces:
1) OTN inter-domain interface (IrDI)
2) OTN intra-domain interface (IaDI)
3) both
both
OTN interface IrDI stands for
OTN inter-domain interface
OTN interface IaDI stands for
OTN intra-domain interface
____ interface is defined with 3R
1) IrDI
2) IaDI
IrDI
____ can potentially have proprietary
features added such as a more powerful FEC
1) IrDI
2) IaDI
IaDI
(IaDI is typically between equipment of the same vendor)
This interface connects the networks
of two operators, or the subnetworks of one or multiple vendors in the
same operator domain
1) IrDI
2) IaDI
IrDI
This interface connects networks
within one operator and vendor domain
1) IrDI
2) IaDI
IaDI
FCAPS management functions stands for
fault, configuration, accounting, performance, and security management
For MPLS-TP The operator has the choice to
1) enable the control plane
2) to operate the network in a traditional way without control plane by means of an NMS
3) any of the above
any of the above.
control plane does not make the NMS obsolete – the NMS needs to configure the control plane and also needs to interact with the control plane for connection management purposes.
The features from MPLS that are not supported by MPLS-TP are:
1) MPLS Control Plane
2) Penultimate Hop Popping (PHP)
3) LSP Merge
4) Equal Cost Multi Path
all of them
MPLS-TP _______ (requires/does not require) LDP or any other control plane protocol to set up the circuits.
does not require
PHP was disabled in MPLS-TP because
1) cause problem with QoS
2) cause problem with path
cause problem with QoS
MPLS-TP mandates the support of
1) bidirectional LSPs
2) point-to-multipoint paths
both
MPLS-TP nodes should be able to work with no control plane
T
MPLS nodes usually use in-band management or
at least in-band exchange of control-plane messages. MPLS-TP network elements have to support _______
1) in-band management
2) out-of-band management
out-of-band management over a dedicated management network
Data forwarding within an MPLS-TP network element _______ even if its management or
control plane fails
1) may fail
2) must continue
must continue
MPLS-TP network elements must be able to run without IP in the forwarding plane
T
MPLS-TP thus includes mandatory support
for numerous ring-specific mechanisms
T
As compared to MPLS/GMPLS ___ are not required for MPLS-TP
1) LDP
2) BGP
3) PHP
4) LSP
1,2,3
How many columns in OTN frame structure
1) 4080
2) 270
3) 1040
4) 3080
4080
What is the Payload Capacity of OUT-4
1) 2.5 Gbps
2) 10 Gbps
3) 40Gbps
4) 100Gbps
100Gbps
OTU-0: 1.25Gbps
OTU-1: 2.5Gbps
OTU-2: 4Gbps
OTU-3: 10Gbps
Solomon code refers to
1) generating path overhead]
2) implementation of FEC code
implementation of FEC code
OTN ODU similar to SDH
1) RSOH
2) POH
3) MSOH
MSOH
OPU similar Ho POH
OPU Payload similar to C-4 Payload
Overheads in the optical domain is transported via
1) in band channel
2) out-of-band channel
out-of-band channel OSC
optical supervisory channel
