Optical Transport Network (OTN) Testing
OTN as per ITU-T G.709 has recently introduced two new concepts: ODU0 and ODUflex. ODU0 is a new virtual container of 1.25 Gbit/s bandwidth specifically defined for efficiently mapping Gigabit Ethernet services over OTN. As for ODUflex, it is the most efficient sub-wavelength bandwidth management capability for transport line rates of 10 Gbit/s, 40 Gbit/s and upcoming 100 Gbit/s. ODUflex allows providers to interconnect routers in ways that enable efficient bandwidth growth in steps of 1.25 Gbit/s, eliminating the need to allocate a full fixed-rate ODU container to each connection and allowing service providers to transport efficiently and seamlessly across lower-cost optical infrastructures.
In addition to testing traditional SONET/SDH and Ethernet interfaces and services, the IQS-8120NGE/8130NGE Power Blazer modules offer OTN test capabilities for verifying compliancy with ITU-T G.709 standards. The tests include:
- OTU1 (2.7 Gbit/s) and OTU2 (10.7 Gbit/s) bit rates
- ODU0 (1.25 Gbit/s) container with Gigabit Ethernet and SONET/SDH client signals mapping
- ODUflex with Ethernet client signal mapping
- Over-clocked OTU2 rates: OTU1e (11.0491 Gbit/s), OTU2e (11.0957 Gbit/s), OTU1f (11.2701 Gbit/s) and OTU2f (11.3176 Gbit/s)
- Unframed optical signal testing at 10.7 Gbit/s, 11.0491 Gbit/s, 11.0957 Gbit/s, 11.2701 Gbit/s and 11.3176 Gbit/s rates
- Synchronous mapping of SONET/SDH signals within OTN as well as synchronous and asynchronous demapping
- Forward error correction (FEC) testing
- Service disruption time (SDT) measurements
- Multichannel SDT measurements and real-time error/alarm monitoring for all ODU0 channels
- Round-trip delay (RTD) measurements
- OTU, ODU, OPU overhead manipulation and monitoring
- OTU, ODU (including ODU TCM), OPU layer alarms/errors generation and analysis
- OTU, ODU (including ODU TCM) trace messages
- Mux/demux of ODU1/ODU2 testing; generation of four ODU1 into a single ODU2 structure and transporting it over a single wavelength
- ODU multiplexing alarm-generation and analysis
- Through mode analysis
- Intrusive Through mode
- EoOTN testing using internally generated 10 GigE LAN and mapping onto OTU1e and OTU2e rate
- 10 GigE LAN mapping into OTU2 using GFP-F
Next-Generation SONET/SDH Testing
Available next-generation SONET/SDH test functionalities include generic framing procedure (GFP), virtual concatenation (VCAT) and link capacity adjustment scheme (LCAS).
- Generation and analysis of frame types (client management/client data)
- Alarm/error generation and monitoring
- Overhead manipulation and monitoring
- Transmission and reception statistics monitoring
- Supported over contiguous or VCAT containers
- High-order and low-order VCAT support
- Simultaneous manipulation and monitoring of each member
- Alarm/error generation and monitoring
- Sequence-indicator manipulation and processing
- Group-summary monitoring
- Differential delay analysis and insertion
- Emulation and analysis of LCAS protocol (Automatic and Manual modes)
- Source and sink state machines control and monitoring
- Real-time generation and monitoring of LCAS control fields
- Real-time insertion and monitoring of LCAS alarms/errors
SmartMode: Real-Time Signal Structure Discovery and Monitoring
EXFO’s IQS-8120NGE/8130NGE Power Blazer modules support a unique feature called SmartMode. This provides users with full visibility of all high-order (STS/AU) and low-order (VT/TU) mixed mappings within the incoming SONET/SDH test signal.
SmartMode automatically discovers the signal structure of the OC-n/STM-n line including mixed mappings and virtual concatenation (VCAT) members. In addition to this in-depth multichannel visibility, SmartMode performs real-time monitoring of all discovered high-order paths and user-selected low-order paths simultaneously, providing users with the industry’s most powerful SONET/SDH multichannel monitoring and troubleshooting solution. Real-time monitoring allows users to rapidly troubleshoot software problems, saving valuable time and minimizing debugging time. SmartMode also provides one-touch test case start, allowing users to quickly configure a desired test path and SmartMode specific reporting.
Ethernet Performance Validation and Reliability
EXFO’s IQS-8120NGE/8130NGE Power Blazers offer a wide range of Ethernet test functions aimed at performance validation and reliability testing.
These modules support multiple Ethernet interfaces, both electrical and optical.
|1000 Mbit/s (GigE)
||10 Gbit/s (10 GigE)—IQS-8130NGE only
The IQS-8120NGE/8130NGE Power Blazer modules deliver the features required to perform Ethernet service acceptance testing, namely RFC 2544 and BER testing.
EtherSAM: The New Standard in Ethernet Testing
ITU-T Y.1564 is the new standard for turning up and troubleshooting Carrier Ethernet services. This methodology is completely adapted to today’s Ethernet services especially mobile backhaul and commercial services. Up to now, RFC 2544 has been the most widely used methodology. However, it was designed for network device testing in the lab, not for services testing in the field. ITU-T Y.1564 is the first testing standard developed for the field. It has a number of advantages over the RFC 2544 including validation of critical SLA criteria such as packet jitter and QoS measurements. This methodology is also significantly faster, therefore saving time and resources while optimizing QoS.
Contrary to other methodologies, EtherSAM supports new multiservice offerings. It can simulate all types of services that will run on the network and simultaneously qualify all key SLA parameters for each of these services. Moreover, it validates the QoS mechanisms provisioned in the network to prioritize the different service types, resulting in more accurate validation and much faster deployment and troubleshooting. EtherSAM is comprised of two phases, the service configuration test and the service performance test.
Service Configuration Test
The service configuration test consists in sequentially testing each service. It validates that the service is properly provisioned and that all specific KPIs or SLA parameters are met. A ramp test and a burst test are performed to verify the committed information rate (CIR), excess information rate (EIR), committed burst size (CBS) and excess burst size (EBS).
Service Performance Test
Once the configuration of each individual service is validated, the service performance test simultaneously validates the quality of all the services over time.
EtherSAM Bidirectional Results
EXFO’s EtherSAM approach proves even more powerful as it executes the complete ITU-T Y.1564 test with bidirectional measurements. Key SLA parameters are measured independently in each test direction, thus providing 100 % first-time-right service activation—that is the highest level of confidence in service testing.
RFC 2544 Testing
In cases where the Ethernet service is delivered via switched transport, the RFC 2544 measurements provide a baseline for service providers to define SLAs with their customers. They enable service providers to validate the quality of service (QoS) delivered and can provide them with a tool to create value-added services that can be measured and demonstrated to customers. For example, these tests provide performance statistics and commissioning verification for virtual LANs (VLANs), virtual private networks (VPNs) and transparent LAN services (TLS), all of which use Ethernet as an access technology.
The IQS-8120NGE/8130NGE Power Blazer modules come with a complete set of RFC 2544 test capabilities, including:
- Throughput testing
- Burst (back-to-back) testing
- Frame loss analysis
- Latency measurement
Because the transparent transport of Ethernet services over physical media is becoming common, Ethernet is increasingly carried across a variety of layer 1 media over longer distances. This creates a growing need for the certification of Ethernet transport on a bit-per-bit basis, which can be done using bit-error-rate testing (BERT).
BERT uses a pseudo-random binary sequence (PRBS) encapsulated into an Ethernet frame, making it possible to go from a frame-based error measurement to a bit-error-rate measurement. This provides the bit-per-bit error count accuracy required for the acceptance testing of physical-medium transport systems.
In addition to BER testing, the IQS-8120NGE/8130NGE Power Blazer modules also provide service disruption time (SDT) measurements.
Ethernet Quality of Service Measurements
Data services are making a significant shift toward supporting a variety of applications on the same network. Multiservice offerings such as triple-play services have fuelled the need for QoS testing to ensure the condition and reliability of each service and fully qualify SLA parameters. The IQS-8120NGE/8130NGE allow service providers to simultaneously simulate and qualify different applications through its multiple stream application. The user has the capability to configure up to 10 streams with different Ethernet and IP QoS parameters such as VLAN ID (802.1Q), VLAN Priority (802.1p), VLAN stacking (802.1ad Q-in-Q), ToS and DSCP. Specific stream profiles to transmit voice-over-IP (VoIP), video and data can be selected for each stream. For each stream, measurements for throughput, latency, frame loss and packet jitter (RFC 3393) are available simultaneously, allowing fast and in-depth qualification of all SLA criteria.
PBB-TE and MPLS: Carrier Ethernet Transport Solution Testing
As technologically-sophisticated business and residential consumers continue to drive demand for premium, high-bandwidth data services such as voice and video, service providers worldwide are evolving their transport infrastructures to support these bandwidth and quality intensive services. No longer is an all-IP core sufficient; providers must now expand their IP convergence to the edge/metro network, in a cost-effective, quality-assured manner. Ethernet has long been accepted as an inexpensive, scalable data networking solution in LAN environments. The stringent quality of service expectations require solutions that tap into the cost-effectiveness of Ethernet without sacrificing the benefits of connection-oriented (albeit it costly) time-division multiplexing (TDM) solutions such as SONET/SDH.
Two Ethernet tunneling technologies address these requirements: Provider Backbone Bridge-Traffic Engineering or PBB-TE (also referred to as PBT) and transport MPLS. These two technologies enable connection-oriented Ethernet, providing carriers with a means of offering scalable, reliable and resilient Ethernet services. The PBB-TE and MPLS options on the IQS-8120NGE/8130NGE offer service providers a comprehensive field tool to efficiently qualify Ethernet services from end-to-end, validating metro and core tunneling technologies.
The Internet protocol (IP) and transmission control protocol (TCP) together form the essence of TCP/IP networking. While IP deals with the delivery of packets, TCP provides the integrity and assurance that the data packets transmitted by one host are reliably received at the destination. Applications such as hypertext transfer protocol (HTTP), e-mail or file transfer protocol (FTP) depend on TCP as their delivery assurance mechanism within networks. Customers deploying such applications expect not only physical and link level SLAs from their service providers, but assurance that their TCP traffic requirements will be supported across the network. The TCP throughout feature offers Ethernet service providers the capability of measuring and validating that the services offered to their customers support the TCP traffic performance they expect.
Ethernet Advanced Troubleshooting
The IQS-8120NGE/8130NGE provides a number of advanced features essential for in-depth troubleshooting in the event of network failures or impairments. The advanced filtering option allows the user to configure up to ten filters each with up to four operands, which will be applied to the received Ethernet traffic. Detailed statistics are available for each configured filter providing the user with critical information required to pinpoint specific problems. Other advanced troubleshooting tools include advanced auto-negation and flow-control capabilities.
Fibre Channel Network Integrity Testing
EXFO’s IQS-8120NGE/8130NGE Power Blazer modules also allow comprehensive testing capabilities for Fibre Channel network deployment.
These modules support multiple Fibre Channel interfaces:
Since most SANs cover large distances and Fibre Channel has stringent performance attributes that must be respected, it is imperative to test at each phase of network deployment to ensure appropriate service levels. EXFO’s IQS-8120NGE/8130NGE Fibre Channel option provides full wire-speed traffic generation at FC-0, FC-1 and FC-2 logical layers, allowing BER testing for link integrity measurements. Latency, buffer-to-buffer credit measurements for optimization, and login capabilities that enable end-to-end Fibre Channel network testing features are also supported.
Transmission of frames in a network is not instantaneous and is subject to multiple delays caused by the propagation delay in the fiber and by processing time inside each piece of network equipment. Latency is the total accumulation of delays between two end points. Some applications such as VoIP, video and storage area networks are very sensitive to excess latency.
It is therefore critical for service providers to properly characterize network latency when offering Fibre Channel services. From the latency measurement that they perform, the IQS-8120NGE/8130NGE modules estimate buffer-to-buffer credit value requirements.
Buffer-to-Buffer Credit Estimation
The buffer credit mechanism is the flow engine for Fibre Channel. This is a crucial configuration parameter for optimal network performance. Usually, network administrators calculate the value by taking the traveled distance and the data rate into consideration; however, since latency issues are not considered, poor accuracy is to be expected. The IQS-8120NGE/8130NGE modules are capable of estimating buffer-credit values with respect to latency by calculating the distance according to the round-trip latency time.
Most new-generation transport devices (xWDM or SONET/SDH MUX) supporting Fibre Channel are no longer fully transparent; they also have increased built-in intelligence, acting more as Fibre-Channel switches. With switch fabric login ability, the IQS-8120NGE/8130NGE modules support connections to a remote location through a fabric or semi-transparent networks.
The login process not only permits the unit to connect through a fabric, but it also exchanges some of the basic port characteristics (such as buffer-to-buffer credit and class of service) in order to efficiently transport the traffic through the network.
The login feature allows automatic detection of port/fabric login, login status (successful login, in progress, failure and logout) and response to remote buffer-to-buffer advertised credit.
Powerful Automated Test Scripting
Automation and scripting, traditionally found in manufacturing applications, is gaining momentum in system verification testing environments to facilitate repeatability and improve quality and efficiency. EXFO’s automation functionality addresses specific requirements of both environments. The IQS-8120NGE/8130NGE Power Blazers include a wide range of SCPI commands (standard commands for programmable instrumentation), which are powerful enough to provide repeatable testing of complex configurations, yet simple enough to create a 10 gigabit SONET/SDH BERT in as little as six commands. As with all IQS-81xx modules, the IQS-8120NGE/8130NGE modules include an intuitive macro recorder enabling users to easily record test actions and automatically create test scripts in VB.Net.
Part of EXFO’s Layer 0/1/2/3/4 Unified Testing Solution
EXFO’s IQS-600 platform supports a mix of physical interfaces and protocol modules (SONET/SDH, Ethernet and Fibre Channel), making it the industry’s first truly integrated and unified testing platform. This multilayer, multitechnology modular test platform simplifies upgrades and is the ideal solution for SVT, manufacturing and R&D testing environments.
Combined with EXFO’s PMD, wavelength and optical spectrum analyzers, the IQS-8120NGE/8130NGE modules are a unique integrated solution addressing all testing requirements from the physical to the transmission layer.
Flexible Remote Access Solution
Through their optional Visual Guardian Lite™management software, the IQS-8120NGE/8130NGE Power Blazers support remote testing, monitoring and data analysis via standard Ethernet with the same familiar user interface. In addition, users can remotely access the IQS-600 platform with a simple Web browser, a VNC client or a Remote Desktop to control any module housed in the platform.
Product Option Flexibility
With the IQS-8120NGE and IQS-8130NGE Power Blazer modules, users can purchase one or more next-generation options (e.g., GFP, VCAT, LCAS) and/or OTN options (OTU1, OTU2) via field upgrades to customize their configuration as new needs arise. This avoids having to perform complete hardware and/or platform retrofits, therefore significantly decreasing capital and training expenses.