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Optical Transport
Network (OTN) Wrapper feature provides robust transport services that leverage
many of the benefits such as resiliency and performance monitoring, while
adding enhanced multi-rate capabilities in support of packet traffic, plus the
transparency required by Dense Wavelength Division Multiplexing (DWDM)
networks. OTN is the ideal technology to bridge the gap between next generation
IP and legacy Time Division Multiplexing (TDM) networks by acting as a
converged transport layer for newer packet-based and existing TDM services. OTN
is defined in ITU G.709 and allows network operators to converge networks
through seamless transport of the numerous types of legacy protocols, while
providing the flexibility required to support future client protocols.
OTN Wrapper feature is
supported on the following interface modules:
8-port 10 Gigabit Ethernet Interface Module (8x10GE) (A900-IMA8Z)(NCS4200-8T-PS) - The encapsulation type is OTU1e and OTU2e.
2-port 40 Gigabit Ethernet QSFP Interface Module (2x40GE) (A900-IMA2F)(NCS4200-2Q-P) - The encapsulation type is OTU3.
1-port 100 Gigabit Ethernet Interface Module (1X100GE) (NCS4200-1H-PK)(A900-IMA1C) - The encapsulation type is OTU4.
The chassis acts as an aggregator for ethernet, TDM, and SONET traffic to connect to an OTN network and vice versa. The ports
on the interface modules are capable of OTN functionality. The OTN controller mode enables the IPoDWDM technology in the interface
modules. The OTN Wrapper encapsulates 10G LAN, 40G LAN, into the corresponding OTU1e or OTU2e, OTU3 containers, respectively.
This enables the ports of the interface modules to work in layer 1 optical mode in conformance with standard G.709.
Figure 1. OTN Signal
Structure
OTN Frame
The key sections of
the OTN frame are the Optical Channel Transport Unit (OTU) overhead section,
Optical Channel Data Unit (ODU) overhead section, Optical Channel Payload Unit
(OPU) overhead section, OPU payload section, and Forward Error Correction (FEC)
overhead section . The network routes these OTN frames across the network in a
connection-oriented way. The Overhead carries the information required to
identify, control and manage the payload, which maintains the deterministic
quality. The Payload is simply the data transported across the network, while
the FEC corrects errors when they arrive at the receiver. The number of
correctable errors depends on the FEC type.
Advantages of
OTN
The following are the
advantages of OTN:
Provides multi-layer performance monitoring and enhanced maintenance
capability for signals traversing multi-operator networks.
Allows Forward Error Correction (FEC) to improve the system
performance.
Provides enhanced alarm handling capability.
Insulates the network against
uncertain service mix by providing transparent native transport of signals
encapsulating all client-management information.
Performs
multiplexing for optimum capacity utilization, thereby improving network
efficiency.
Enables network
scalability as well as support for dedicated Ethernet services with service
definitions.
ODU and OTU
Optical Channel
Transport Unit (OTU) and Optical Channel Data Unit (ODU) are the two digital
layer networks. All client signals are mapped into the optical channel via the
ODU and OTU layer networks.
OTU
The OTU section is composed of two main sections: the Frame Alignment section and the Section Monitoring (SM) section. The
OTU Overhead (OH) provides the error detection correction as well as section-layer connection and monitoring functions on
the section span. The OTU OH also includes framing bytes, enabling receivers to identify frame boundaries. For more information,
see G.709 document.
ODU
The ODU section is an internal element allowing mapping or switching between different rates, which is important in allowing
operators the ability to understand how the end user pipe is transferred through to the higher network rates. The ODU OH contains
path overhead bytes allowing the ability to monitor the performance, fault type and location, generic communication, and six
levels of channel protection based on Tandem Connection Monitoring (TCM). For more information, see G.709 document.
OTU1e and OTU 2e
Support on 8x10GE Interface Module
The OTU1e and OTU2e
are mapping mechanisms to map a client 10G Base-R signal to OTN frames
transparently as per ITU-T G series Supplement 43 specification. Both these
modes are over-clocked OTN modes. These mechanisms provide real bit
transparency of 10 GbE LAN signals and are useful for deployment of 10G
services.
The OTU1e and OTU2e
are inherently intra-domain interfaces (IaDI) and are generally applicable only
to a single vendor island within an operator's network to enable the use of
unique optical technology. The OTU1e and OTU2e are not standard G.709 bit-rate
signals and they do not interwork with the standard mappings of Ethernet using
GFP-F. These two over-clocked mechanisms do not interwork with each other. As a
result, such signals are only deployed in a point-to-point configuration
between equipment that implements the same mapping.
The standard 10 GbE
LAN has a data rate of 10.3125 Gbps. In the OTU1e and OTU2e mapping schemes,
the full 10.3125 Gbit/s is transported including the 64B/66B coded information,
IPG, MAC FCS, preamble, start-of-frame delimiter (SFD) and the ordered sets (to
convey fault information). So, the effective OTU2e and OTU1e rates are:
OTU1e: 11.0491
Gbits/s +/- 100ppm
OTU2e: 11.0957
Gbits/s +/- 100ppm
The 10GBase-R client
signal with fixed stuff bytes is accommodated into an OPU-like signal, then
into an ODU-like signal, and further into an OTU-like signal. These signals are
denoted as OPU2e, ODU2e and OTU2e, respectively . The OTU1e does not add 16
columns of fixed stuff bytes and hence overall data rate is relatively lesser
at 11.0491 Gbps as compared to OTU2e which is 11.0957 Gbps.
The following table
shows the standard OTU rates:
Table 1. Standard OTU
Rates
G.709
Interface
Line Rate
Corresponding
Ethernet Rate
Line Rate
OTU-1e
11.0491 Gbit/s
without stuffing bits
10 Gig E-LAN
10.3125 Gbit/s
OTU-2e
11.0957 Gbit/s
without stuffing bits
10 Gig E-LAN
10.3125 Gbit/s
OTU-3
43.018 Gbit/s
STM-256 or
OC-768
39.813 Gbit/s
Deriving OTU1e and
OTU2e Rates
A standard OTN frame
consists of 255 16-column blocks and the payload rate is 9953280 Kbit/s. This
is because the overhead and stuffing in the OTN frames happen at a granularity
of 16-column blocks. Thus, OPU payload occupies (3824-16)/16=238 blocks. The
ODU occupies 239 blocks and the OTU (including FEC) occupies 255 blocks. Hence,
the multiplication factor in the G.709 spec is specified using numbers like
237, 238, 255.
Since OPU2e uses 16
columns that are reserved for stuffing and also for payload, the effective
OPU2e frequency is:
OPU2e = 238/237 x
10312500 Kbit/s = 10.356012 Gbit/s
ODU2e = 239/237 x
10312500 Kbit/s = 10.399525 Gbit/s
OTU2e = 255/237 x
10312500 Kbit/s = 11.095727 Gbit/s
Since OPU1e uses 16 columns that are reserved for stuffing and also
for payload, the effective OPU1e frequency is:
OPU1e = 238/238 x
10312500 Kbit/s = 10.3125 Gbit/s
ODU1e = 239/238 x
10312500 Kbit/s = 10.355829 Gbit/s
OTU1e = 255/238 x
10312500 Kbit/s = 11.049107 Gbit/s
OTU3 Support in
2x40GE Interface Module
When 40GbE LAN is transported over
OTN, there is no drop in line rate when the LAN client is mapped into the OPU3
using the standard CBR40G mapping procedure as specified in G.709 clause
17.2.3. The 40G Ethernet signal (41.25 Gbit/s) uses 64B/66B coding making it
slightly larger than the OPU3 payload rate that is 40.15 Gbit/s. Hence, to
transport 40G Ethernet service over ODU3, the 64B/66B blocks are transcoded
into 1024B/1027B block code to reduce their size. The resulting 40.117 Gbit/s
transcoded stream is then mapped in standard OPU3.
Supported Transceivers
The OTN wrapper feature works with the standard transceiver types that are supported for the LAN mode of 10G, 40G and 100G
on the interface modules. The SFP-10G-LR-X, QSFP-40G-LR4, are used for 8x10GE, 2x40GE interface modules, respectively.
OTN Specific
Functions
The following figure
shows the OTN specific functions related to overhead processing, alarm
handling, FEC and TTI:
Figure 2. OTN Specific Functions
Standard
MIBS
The following are the standard MIBS:
RFC2665
RFC1213
RFC2907
RFC2233
RFC3591
Restrictions for
OTN
The following are the
restrictions for OTN:
OTL alarms are not
supported.
FECMISMATCH alarm
is not supported.
Enhanced FEC is
not supported.
Alarm and error
counters are visible when the controller is in shutdown state.
DWDM
Provisioning
All DWDM provisioning configurations
take place on the controller. To configure a DWDM controller, use the
controller dwdm command in global configuration mode.
Prerequisites for
DWDM Provisioning
The g709 configuration commands can
be used only when the controller is in the shutdown state. Use the
no shutdown command after configuring the
parameters, to remove the controller from shutdown state and to enable the
controller to move to up state.
Configuring DWDM
Provisioning
Use the following
commands to configure DWDM provisioning:
enableconfigure terminalcontroller dwdm0/1/0
Configuring
Transport Mode in 8x10GE and 2x40GE Interface Modules
Use the
transport-mode command in interface configuration
mode to configure LAN and OTN transport modes in 8x10GE and 2x40GE interface
modules. The
transport-mode command
otn option has the bit-transparent sub-option, using
which bit transparent mapping into OPU1e or OPU2e can be configured.
Use the following
commands to configure LAN and OTN transport modes:
To configure the
transport administration state on a DWDM port, use the
admin-state command in DWDM configuration mode. To
return the administration state from a DWDM port to the default, use the
no form of this command.
Verification of LAN
Transport Mode Configuration
Use the
show
interfaces command to verify the configuration of LAN transport
mode:
Router#sh int te0/1/0
TenGigabitEthernet0/1/0 is up, line protocol is up
MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 8/255, rxload 193/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full Duplex, 10000Mbps, link type is force-up, media type is SFP-SR
output flow-control is unsupported, input flow-control is on
Transport mode LAN
ARP type: ARPA, ARP Timeout 04:00:00
Last input 04:02:09, output 04:02:09, output hang never
Last clearing of "show interface" counters 00:29:47
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 7605807000 bits/sec, 14854906 packets/sec
5 minute output rate 335510000 bits/sec, 655427 packets/sec
26571883351 packets input, 1700600465344 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
10766634813 packets output, 689064271464 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
Router#
Verification of OTN
Transport Mode Configuration in 8x10GE Interface Modules
Use the
show
interfaces command to verify the configuration of OTN transport
mode in 8x10GE interface modules:
Router#sh int te0/1/1
TenGigabitEthernet0/1/1 is up, line protocol is up
MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 193/255, rxload 7/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full Duplex, 10000Mbps, link type is force-up, media type is SFP-SR
output flow-control is unsupported, input flow-control is on
Transport mode OTN (10GBASE-R over OPU1e w/o fixed stuffing, 11.0491Gb/s)
ARP type: ARPA, ARP Timeout 04:00:00
Last input 03:28:14, output 03:28:14, output hang never
Last clearing of "show interface" counters 00:30:47
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 281326000 bits/sec, 549608 packets/sec
5 minute output rate 7596663000 bits/sec, 14837094 packets/sec
10766669034 packets input, 689066159324 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
27457291925 packets output, 1757266795328 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
Router#
Verification of OTN
Transport Mode Configuration in 2x40GE Interface Modules
Use the
show
interfaces command to verify the configuration of OTN transport
mode in 2x40GE interface modules:
Router#show int fo0/4/0
FortyGigabitEthernet0/4/0 is up, line protocol is up
MTU 1500 bytes, BW 40000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full Duplex, 40000Mbps, link type is force-up, media type is QSFP_40GE_SR
output flow-control is unsupported, input flow-control is on
Transport mode OTN OTU3 (43.018Gb/s)
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
Changing from OTN to
LAN Mode
Use the following
methods to change from OTN mode to LAN mode:
Use the following
commands to make the transport mode as LAN mode:
OTN supports alarms in
each layer of encapsulation. All the alarms follow an alarm hierarchy and the
highest level of alarm is asserted and presented as a Syslog message or on the
CLI.
OTU Alarms
The types of alarms
enabled for reporting:
AIS - Alarm
indication signal (AIS) alarms
BDI - Backward
defect indication (BDI) alarms
IAE - Incoming
alignment error (IAE) alarms
LOF - Loss of
frame (LOF) alarms
LOM - Loss of
multiple frames (LOM) alarms
LOS - Loss of
signal (LOS) alarms
TIM - Type
identifier mismatch (TIM) alarms
SM - TCA - SM
threshold crossing alert
SD-BER - SM BER
is in excess of the SD BER threshold
SF-BER - SM BER
is in excess of the SF BER threshold
ODU Alarms
The types of alarms
enabled for reporting:
AIS - Alarm
indication signal (AIS) alarms
BDI - Backward
defect indication (BDI) alarms
LCK - Upstream
connection locked (LCK) error status
OCI - Open
connection indication (OCI) error status
Use
no g709
odu threshold command to disable configuration of ODU threshold.
Verification of OTU
and ODU Threshold Configuration
Use the
show
controllers command to verify OTU and ODU threshold configuration:
Router#show controllers dwdm 0/1/2
G709 Information:
Controller dwdm 0/1/2, is up (no shutdown)
Transport mode OTN (10GBASE-R over OPU1e w/o fixed stuffing, 11.0491Gb/s)
Loopback mode enabled : None
TAS state is : UNKNWN
G709 status : Enabled
OTU
LOS = 0 LOF = 0 LOM = 0
AIS = 0 BDI = 0 BIP = 0
TIM = 0 IAE = 0 BEI = 0
ODU
AIS = 0 BDI = 0 TIM = 0
OCI = 0 LCK = 0 PTIM = 0
BIP = 0 BEI = 0
FEC Mode: FEC
Remote FEC Mode: Unknown
FECM = 0
EC(current second) = 0
EC = 0
UC = 0
Detected Alarms: NONE
Asserted Alarms: NONE
Detected Alerts: NONE
Asserted Alerts: NONE
Alarm reporting enabled for: LOS LOF LOM OTU-AIS OTU-IAE OTU-BDI OTU-TIM ODU-AIS ODU-OCI ODU-LCK ODU-BDI ODU-PTIM ODU-TIM ODU-BIP
Alert reporting enabled for: OTU-SD-BER OTU-SF-BER OTU-SM-TCA ODU-SD-BER ODU-SF-BER ODU-PM-TCA
BER thresholds: ODU-SF = 10e-3 ODU-SD = 10e-6 OTU-SF = 10e-3 OTU-SD = 10e-6
TCA thresholds: SM = 10e-3 PM = 10e-3
OTU TTI Sent String SAPI ASCII : AABBCCDD
OTU TTI Sent String DAPI ASCII : AABBCCDD
OTU TTI Sent String OPERATOR ASCII : AABBCCDD
OTU TTI Expected String SAPI ASCII : AABBCCDD
OTU TTI Expected String DAPI ASCII : AABBCCDD
OTU TTI Expected String OPERATOR HEX : AABBCCDD
OTU TTI Received String HEX : 0052414D4553480000000000000000000052414D455348000
0000000000000004141424243434444000000000000000000
000000000000000000000000000000
ODU TTI Sent String SAPI ASCII : AABBCCDD
ODU TTI Sent String DAPI ASCII : AABBCCDD
ODU TTI Sent String OPERATOR HEX : 11223344
ODU TTI Expected String SAPI ASCII : AABBCCDD
ODU TTI Expected String DAPI ASCII : AABBCCDD
ODU TTI Expected String OPERATOR HEX : 11223344
ODU TTI Received String HEX : 0052414D4553480000000000000000000052414D455348000
0000000000000001122334400000000000000000000000000
000000000000000000000000000000
Router#
Configuring OTU
Alerts
To configure OTU
alerts:
enableconfigure terminalcontroller dwdm0/4/1shutdowng709otug709 otuthresholdg709 otu thresholdsd-berno shutdownend
Configuring ODU
Alerts
To configure ODU
alerts:
enableconfigure terminalcontroller dwdm0/4/1shutdowng709otug709 otuthresholdg709 otu thresholdpm-tcano shutdownend
Configuring ODU
Alerts
To configure ODU
alerts:
enableconfigure terminalcontroller dwdm0/4/1shutdowng709otug709 otuthresholdg709 otu thresholdpm-tcano shutdownend
Verifying Alerts
Configuration
Use the show controllers command to
verify the alerts configuration:
#show controllers dwdm 0/4/1
G709 Information:
Controller dwdm 0/4/1, is down (shutdown)
Transport mode OTN OTU3
Loopback mode enabled : Line
TAS state is : IS
G709 status : Enabled
OTU
LOS = 5 LOF = 1 LOM = 0
AIS = 0 BDI = 0 BIP = 149549
TIM = 0 IAE = 0 BEI = 74685
ODU
AIS = 0 BDI = 0 TIM = 0
OCI = 0 LCK = 0 PTIM = 0
BIP = 2 BEI = 0
FEC Mode: FEC
Remote FEC Mode: Unknown
FECM = 0
EC(current second) = 0
EC = 856
UC = 23165
Detected Alarms: NONE
Asserted Alarms: NONE
Detected Alerts: NONE
Asserted Alerts: NONE
Alarm reporting enabled for: LOS LOF LOM OTU-AIS OTU-IAE OTU-BDI ODU-AIS ODU-OCI ODU-LCK ODU-BDI ODU-PTIM ODU-BIP
Alert reporting enabled for: OTU-SD-BER OTU-SF-BER OTU-SM-TCA ODU-SD-BER ODU-SF-BER ODU-PM-TCA
BER thresholds: ODU-SF = 10e-3 ODU-SD = 10e-6 OTU-SF = 10e-3 OTU-SD = 10e-5
TCA thresholds: SM = 10e-3 PM = 10e-4
OTU TTI Sent String SAPI ASCII : Tx TTI Not Configured
OTU TTI Sent String DAPI ASCII : Tx TTI Not Configured
OTU TTI Sent String OPERATOR ASCII : Tx TTI Not Configured
OTU TTI Expected String SAPI ASCII : Exp TTI Not Configured
OTU TTI Expected String DAPI ASCII : Exp TTI Not Configured
OTU TTI Expected String OPERATOR ASCII : Exp TTI Not Configured
OTU TTI Received String HEX : 0000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000
000000000000000000000000000000
ODU TTI Sent String SAPI ASCII : Tx TTI Not Configured
ODU TTI Sent String DAPI ASCII : Tx TTI Not Configured
ODU TTI Sent String OPERATOR ASCII : Tx TTI Not Configured
ODU TTI Expected String SAPI ASCII : Exp TTI Not Configured
ODU TTI Expected String DAPI ASCII : Exp TTI Not Configured
ODU TTI Expected String OPERATOR ASCII : Exp TTI Not Configured
ODU TTI Received String HEX : 0000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000
000000000000000000000000000000
Loopback
Loopback provides a means for
remotely testing the throughput of an Ethernet port on the router. You can
verify the maximum rate of frame transmission with no frame loss. Two types of
loopback is supported:
Internal Loopback - All
packets are looped back internally within the router before reaching an
external cable. It tests the internal Rx to Tx path and stops the traffic to
egress out from the Physical port.
Line Loopback - Incoming network packets are looped back through the
external cable.
Forward error
correction (FEC) is a method of obtaining error control in data transmission in
which the source (transmitter) sends redundant data and the destination
(receiver) recognizes only the portion of the data that contains no apparent
errors. FEC groups source packets into blocks and applies protection to
generate a desired number of repair packets. These repair packets may be sent
on demand or independently of any receiver feedback.
Standard FEC is supported on 8x10GE and 2x40GE interface modules.
The packets that can
be corrected by FEC are known as Error Corrected Packets. The packets that
cannot be corrected by FEC due to enhanced bit errors are known as Uncorrected
Packets.
Benefits of
FEC
The following are the
benefits of FEC:
FEC reduces the number of
transmission errors, extends the operating range, and reduces the power
requirements for communications systems.
FEC increases the
effective systems throughput.
FEC supports correction of bit errors occurring due to impairments
in the transmission medium.
Use the
show controllers command to verify FEC
configuration:
G709 Information:
Controller dwdm 0/4/1, is up (no shutdown)
Transport mode OTN OTU3
Loopback mode enabled : Line
TAS state is : IS
G709 status : Enabled
OTU
LOS = 5 LOF = 1 LOM = 0
AIS = 0 BDI = 0 BIP = 149549
TIM = 0 IAE = 0 BEI = 74685
ODU
AIS = 0 BDI = 0 TIM = 0
OCI = 0 LCK = 0 PTIM = 0
BIP = 2 BEI = 0
FEC Mode: FEC
Remote FEC Mode: Unknown <— This is a limitation by which we do not show the remote FEC mode
FECM = 0
EC(current second) = 0
EC = 856 < — This is the counter for Error corrected bits .
UC = 23165 <- this is the counter for Uncorrected alarms .
Detected Alarms: NONE
Asserted Alarms: NONE
Detected Alerts: NONE
Asserted Alerts: NONE
Alarm reporting enabled for: LOS LOF LOM OTU-AIS OTU-IAE OTU-BDI ODU-AIS ODU-OCI ODU-LCK ODU-BDI ODU-PTIM ODU-BIP
Alert reporting enabled for: OTU-SD-BER OTU-SF-BER OTU-SM-TCA ODU-SD-BER ODU-SF-BER ODU-PM-TCA
BER thresholds: ODU-SF = 10e-3 ODU-SD = 10e-6 OTU-SF = 10e-3 OTU-SD = 10e-5
TCA thresholds: SM = 10e-3 PM = 10e-4
OTU TTI Sent String SAPI ASCII : Tx TTI Not Configured
OTU TTI Sent String DAPI ASCII : Tx TTI Not Configured
OTU TTI Sent String OPERATOR ASCII : Tx TTI Not Configured
OTU TTI Expected String SAPI ASCII : Exp TTI Not Configured
OTU TTI Expected String DAPI ASCII : Exp TTI Not Configured
OTU TTI Expected String OPERATOR ASCII : Exp TTI Not Configured
OTU TTI Received String HEX : 0000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000
000000000000000000000000000000
ODU TTI Sent String SAPI ASCII : Tx TTI Not Configured
ODU TTI Sent String DAPI ASCII : Tx TTI Not Configured
ODU TTI Sent String OPERATOR ASCII : Tx TTI Not Configured
ODU TTI Expected String SAPI ASCII : Exp TTI Not Configured
ODU TTI Expected String DAPI ASCII : Exp TTI Not Configured
ODU TTI Expected String OPERATOR ASCII : Exp TTI Not Configured
ODU TTI Received String HEX : 0000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000
Trail Trace
Identifier
The Trail Trace
Identifier (TTI) is a 64-Byte signal that occupies one byte of the frame and is
aligned with the OTUk multiframe. It is transmitted four times per multiframe.
TTI is defined as a 64-byte string with the following structure:
TTI [0] contains the Source
Access Point Identifier (SAPI) [0] character, which is fixed to all-0s.
TTI [1] to TTI
[15] contain the 15-character source access point identifier (SAPI[1] to
SAPI[15]).
TTI [16] contains
the Destination Access Point Identifier (DAPI) [0] character, which is fixed to
all-0s.
TTI [17] to TTI
[31] contain the 15-character destination access point identifier (DAPI [1] to
DAPI [15]).
TTI [32] to TTI
[63] are operator specific.
TTI Mismatch
TTI mismatch occurs
when you have enabled path trace and the "received string" is different from
the "expected string". This alarm condition stops traffic.
When TTI mismatch
occurs, the interface is brought to down state. This is only supported for SAPI
and DAPI and is not supported for
User Operator Data field.
Trace Identifier
Mismatch (TIM) is reported in the Detected Alarms where there is a mismatch in
the expected and received string. Action on detection of TIM can be configured
in ODU and OTU layers as follows:
Configuring TTI for
SAPI DAPI Operator Specific Fields
To configure TTI SAPI,
DAPI, and operator specific fields for OTU and ODU layers:
enableconfigure terminalcontroller dwdm0/1/1g709 fecstandardg709 otu overhead ttisentascii sapiAABBCCDD
end
Verification of TTI
SAPI DAPI Operator Specific Fields Configuration
Use the show
controller command to verify TTI SAPI, DAPI, Operator Specific fields
configuration:
Router#show controllers dwdm 0/1/1
G709 Information:
Controller dwdm 0/1/1, is up (no shutdown)
Transport mode OTN (10GBASE-R over OPU1e w/o fixed stuffing, 11.0491Gb/s)
<<truncated other output >>
OTU TTI Sent String SAPI ASCII : AABBCCDD
OTU TTI Sent String DAPI ASCII : AABBCCDD
OTU TTI Sent String OPERATOR ASCII : AABBCCDD
OTU TTI Expected String SAPI ASCII : AABBCCDD
OTU TTI Expected String DAPI ASCII : AABBCCDD
OTU TTI Expected String OPERATOR HEX : AABBCCDD
OTU TTI Received String HEX : 0052414D4553480000000000000000000052414D455348000
0000000000000004141424243434444000000000000000000
000000000000000000000000000000
ODU TTI Sent String SAPI ASCII : AABBCCDD
ODU TTI Sent String DAPI ASCII : AABBCCDD
ODU TTI Sent String OPERATOR HEX : 11223344
ODU TTI Expected String SAPI ASCII : AABBCCDD
Verifying Loopback
Configuration
Use the
show controllers command to verify the loopback
configuration:
#show controllers dwdm 0/4/1
G709 Information:
Controller dwdm 0/4/1, is up (no shutdown)
Transport mode OTN OTU3
Loopback mode enabled : Line
TAS state is : IS
G709 status : Enabled
OTU
LOS = 5 LOF = 1 LOM = 0
AIS = 0 BDI = 0 BIP = 149549
TIM = 0 IAE = 0 BEI = 74685
ODU
AIS = 0 BDI = 0 TIM = 0
OCI = 0 LCK = 0 PTIM = 0
BIP = 2 BEI = 0
FEC Mode: FEC
Remote FEC Mode: Unknown
FECM = 0
EC(current second) = 0
EC = 856
UC = 23165
Detected Alarms: NONE
Asserted Alarms: NONE
Detected Alerts: NONE
Asserted Alerts: NONE
Alarm reporting enabled for: LOS LOF LOM OTU-AIS OTU-IAE OTU-BDI ODU-AIS ODU-OCI ODU-LCK ODU-BDI ODU-PTIM ODU-BIP
Alert reporting enabled for: OTU-SD-BER OTU-SF-BER OTU-SM-TCA ODU-SD-BER ODU-SF-BER ODU-PM-TCA
BER thresholds: ODU-SF = 10e-3 ODU-SD = 10e-6 OTU-SF = 10e-3 OTU-SD = 10e-4
TCA thresholds: SM = 10e-3 PM = 10e-3
OTU TTI Sent String SAPI ASCII : Tx TTI Not Configured
OTU TTI Sent String DAPI ASCII : Tx TTI Not Configured
OTU TTI Sent String OPERATOR ASCII : Tx TTI Not Configured
OTU TTI Expected String SAPI ASCII : Exp TTI Not Configured
OTU TTI Expected String DAPI ASCII : Exp TTI Not Configured
OTU TTI Expected String OPERATOR ASCII : Exp TTI Not Configured
OTU TTI Received String HEX : 0000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000
000000000000000000000000000000
ODU TTI Sent String SAPI ASCII : Tx TTI Not Configured
ODU TTI Sent String DAPI ASCII : Tx TTI Not Configured
ODU TTI Sent String OPERATOR ASCII : Tx TTI Not Configured
ODU TTI Expected String SAPI ASCII : Exp TTI Not Configured
ODU TTI Expected String DAPI ASCII : Exp TTI Not Configured
ODU TTI Expected String OPERATOR ASCII : Exp TTI Not Configured
ODU TTI Received String HEX : 0000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000
000000000000000000000000000000
#
SNMP Support
Simple Network
Management Protocol (SNMP) is an application-layer protocol that provides a
message format for communication between SNMP managers and agents. SNMP
provides a standardized framework and a common language that is used for
monitoring and managing devices in a network.
SNMP sets are not
supported for the following tables:
coiIfControllerTable
coiOtnNearEndThresholdsTable
coiOtnFarEndThresholdsTable
coiFECThresholdsTable
Refer to
CISCO-OTN-IF-MIB and
SNMP Configuration
Guide for SNMP support.
Performance
Monitoring
Performance
monitoring (PM) parameters are used by service providers to gather, store, set
thresholds for, and report performance data for early detection of problems.
Thresholds are used to set error levels for each PM parameter. During the
accumulation cycle, if the current value of a performance monitoring parameter
reaches or exceeds its corresponding threshold value, a threshold crossing
alert (TCA) is generated. The TCAs provide early detection of performance
degradation. PM statistics are accumulated on a 15-minute basis, synchronized
to the start of each quarter-hour. Historical counts are maintained for 33
15-minutes intervals and 2 daily intervals. PM parameters are collected for OTN
and FEC.
Calculation and
accumulation of the performance-monitoring data is in 15-minute and 24-hour
intervals.
PM parameters require the errored ratio to be less than the standard
reference that is dependent on the encapsulation. If any loss or error event
does not happen within a second, it is called an error free second. If some
error in transmission or alarm happens in a second, the second is called
Errored Second. The error is termed as Errored Second or Severely Errored
Second or Unavailable Second depending upon the nature of error. The error
calculation depends on the Errored Blocks. Errored second is a second where one
BIP error or BEI error occurs. Severely Errored Second occurs when the errored
frames crosses a threshold or there is an alarm is generated. Unavaliable
Second occurs when there are 10 consecutive severely errored seconds.
Figure 3. Performance Monitoring
PM occurs in near end and far end for both encapsulations for ODUk and
OTUk. ODU is referred as Path Monitoring (PM) and OTU is referred to as Section
Monitoring (SM).
The following table
shows the details of each type of PM parameter for OTN:
Table 2. PM Parameters for
OTN
Parameter
Definition
BBE-PM
Path
Monitoring Background Block Errors (BBE-PM) indicates the number of background
block errors recorded in the optical transport network (OTN) path during the PM
time interval.
BBE-SM
Section
Monitoring Background Block Errors (BBE-SM) indicates the number of background
block errors recorded in the OTN section during the PM time interval.
BBER-PM
Path
Monitoring Background Block Errors Ratio (BBER-PM) indicates the background
block errors ratio recorded in the OTN path during the PM time interval.
BBER-SM
Section
Monitoring Background Block Errors Ratio (BBER-SM) indicates the background
block errors ratio recorded in the OTN section during the PM time interval.
ES-PM
Path
Monitoring Errored Seconds (ES-PM) indicates the errored seconds recorded in
the OTN path during the PM time interval.
ESR-PM
Path
Monitoring Errored Seconds Ratio (ESR-PM) indicates the errored seconds ratio
recorded in the OTN path during the PM time interval.
ESR-SM
Section
Monitoring Errored Seconds Ratio (ESR-SM) indicates the errored seconds ratio
recorded in the OTN section during the PM time interval.
ES-SM
Section
Monitoring Errored Seconds (ES-SM) indicates the errored seconds recorded in
the OTN section during the PM time interval.
FC-PM
Path
Monitoring Failure Counts (FC-PM) indicates the failure counts recorded in the
OTN path during the PM time interval.
FC-SM
Section
Monitoring Failure Counts (FC-SM) indicates the failure counts recorded in the
OTN section during the PM time interval.
SES-PM
Path
Monitoring Severely Errored Seconds (SES-PM) indicates the severely errored
seconds recorded in the OTN path during the PM time interval.
SES-SM
Section
Monitoring Severely Errored Seconds (SES-SM) indicates the severely errored
seconds recorded in the OTN section during the PM time interval.
SESR-PM
Path
Monitoring Severely Errored Seconds Ratio (SESR-PM) indicates the severely
errored seconds ratio recorded in the OTN path during the PM time interval.
SESR-SM
Section
Monitoring Severely Errored Seconds Ratio (SESR-SM) indicates the severely
errored seconds ratio recorded in the OTN section during the PM time interval.
UAS-PM
Path
Monitoring Unavailable Seconds (UAS-PM) indicates the unavailable seconds
recorded in the OTN path during the PM time interval.
UAS-SM
Section
Monitoring Unavailable Seconds (UAS-SM) indicates the unavailable seconds
recorded in the OTN section during the PM time interval.
The following table
shows the details of each type of PM parameter for FEC:
Table 3. PM Parameters
for FEC
Parameter
Definition
EC
Bit Errors
Corrected (BIEC) indicated the number of bit errors corrected in the DWDM trunk
line during the PM time interval.
UC-WORDS
Uncorrectable Words (UC-WORDS) is the number of uncorrectable words detected in
the DWDM trunk line during the PM time interval.
OTUk Section
Monitoring
Section Monitoring
(SM) overhead for OTUk is terminated as follows:
TTI
BIP
BEI
BDI
IAE
BIAE
BIP and BEI counters
are block error counters (block size equal to OTUk frame size). The counters
can be read periodically by a PM thread to derive one second performance
counts. They are sufficiently wide for software to identify a wrap-around with
up to 1.5 sec between successive readings.
The following OTUk
level defects are detected:
dAIS
dTIM
dBDI
dIAE
dBIAE
Status of the defects
is available through CPU readable registers, and a change of status of dLOF,
dLOM, and dAIS will generate an interruption.
ODUk Path
Monitoring
Path Monitoring (PM)
overhead for higher order ODUk and lower order ODUk is processed as follows:
TTI
BIP
BEI
BDI
STAT including ODU
LCK/OCI/AIS
The following ODUk
defects are detected:
dTIM
dLCK and dAIS
(from STAT field)
dBDI
LOS, OTU LOF, OOF and
ODU-AIS alarms bring down the interface in system.
Configuring PM
Parameters for FEC
To set TCA report
status on FEC layer in 15-minute interval:
Feedback