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T&M; TRENDS: The NextGen Challenge

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Voice&Data Bureau
New Update

Synchronous data transmission over fiber optic networks is achieved by
Synchronous Optical Network (SONET) and synchronous digital hierarchy (SDH).
SONET is the U.S. version of the standard published by American National
Standard Institute (ANSI). SDH is the international version of the standard
published by International Telecommunications union (ITU).

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The First-generation SONET/SDH equipment was add/ drop multiplexer (ADM),
which was based on the original set of standards. Next-generation test equipment
was SONET/SDH switch, with the mechanism of mapping Ethernet on SONET. The
third-generation test equipment uses tools like virtual concatenation (VCAT),
generic framing procedure (GFP), and Link capacity adjustment scheme (LCAS).
Next generation SONET/SDH devices are supporting Resilient Packet Ring (RPR) for
scalability, bandwidth efficiency, class of service support features.

SONET/SDH
is preferred more than plesiochronous digital hierarchy (PDH) because of its
compatibility with standard equipment from different vendors. When sophisticated
services with high bandwidth are required, SONET/SDH finds its importance. SONET/SDH
capitalizes the voice transport ability with high vendor interoperability.

Bench-top SONET/SDH test equipment are generally used in the research and
development and manufacturing applications, where as the portable/hand-held test
equipment are used for installation and maintenance applications. SONET/SDH
operates at different line rates including OC 3, OC 12, OC 48, and OC 768.

Technology

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  • GFP: GFP is a standard to tag traffic adaptation
    features. It provides convergence between packet switched network and the
    transmission network. It uses VCAT to provide right-sized pipes for data
    services. GFP has two modes namely

  1. Frame mode for packet based protocols (Ethernet, PPP, and
    RPR)

  2. Transparent mode for other protocols

  3. LCAS: LCAS is used for the survivability options
    of next-generation SONET services and to dynamically adopt bandwidth based
    on customer's request. LCAS can be used with both high-order and low-order
    VCAT. The blend of customer satisfaction and lower operating cost makes it
    attractive for carriers. Use of LCAS purges the need for manual provisioning
    and enables service upgrade.

  4. VCAT: VCAT enables SONET/SDH transport pipes to be
    right-sized for Ethernet transport. The technology allows SONET/SDH channels
    to be multiplexed in arbitrary arrangements. For SONET, virtual
    concatenation rates are designated by STS-m-nv for high order virtual
    concatenation and by VT-m-nv for low order virtual concatenation.

    For SDH, the rates are designated by VC-m-nv.

  5. RPR: RPR is used to integrate efficiently the
    bandwidth and the packet services support.

  6. A Comparison of Ethernet versus Ethernet-over-RPR
    includes

  7. Ethernet is designed for point-to-point and mesh topology
    networks, not ring topologies

  8. Ethernet has a comparatively less number of protection
    mechanisms

  9. Ethernet has comparatively low fairness policies for
    sharing ring bandwidth

Packet over SONET (POS): It is the traditional way of
transporting packet data directly without an ATM layer. POS encapsulates
frame/packet-based protocols like PPP (point-to-point protocol), Frame Relay,
and Ethernet over HDLC (high-layer data link control) within SONET; it cannot
differentiate the separate packet streams on the link to allow per-stream
traffic engineering, protection, and bandwidth management.

Key elements in Multi Service over SONET/SDH are:

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  • Data optimization of the SONET/SDH transport layer

  • Quality of service (QoS) to achieve service-level
    agreements

  • Opportunities in packet based services over SONET/SDH

Next-generation SONET/SDH Technologies

Agilent technologies Inc. leads in terms of Next generation SONET/SDH
products. Some of the key products of Agilent include OmniBER OTN, OmniBER XM
and N2X transport solution. Agilent's N2X tester combines the edge service
testing with carrier-grade infrastructure setting. OmniBER OTN is the only
instrument to offer GFP, VCAT, LCAS, Ethernet payload and measurement
capabilities.

EXFO has developed FTB 8100 Next generation SONET/SDH analyzer which gives an
integrated Ethernet support. Multiple testing is eliminated by the use of FTB
8100. The FTB-8100 product family supports test interfaces ranging from DS1/E1
to OC-48/STM-16 with field-expandability to OC-192/STM-64 rates.

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Net test pronounced the ease of use of Next-generation SONET/SDH analysis
option for its CMA 5000 Optical Transport Analysis (OTA) application. Parameters
including VCAT, Differential delay and LCAS can be easily tested by the NEM's
and operators.

For the constantly evolving standards, interoperability poses a serious
challenge as compatibility between the equipment and network is required. VCAT
in next-generation products improves the Ethernet transport efficiency and LCAS
can change the transport bandwidth required. Scalability and interoperability
are the two major challenges to the Next generation SONET/SDH equipments. SONET/SDH
is expected to be the premier transport protocol for the upcoming years as it
has the potential to add metro services through protocol transparency, granular
switching and efficient bandwidth management.

The emblematic usage of next- Generation SONET/SDH is

  • To split the band width between packet and Time division
    multiplexing (TDM) services dynamically

  • To endow with incremental packet bandwidth.

  • To label, multiplex and switch with a diminution in port
    counts over the Classical SONET /SDH architecture.

  • The chip vendors drive their SONET/SDH devices in two
    directions

  • Higher speeds, densities and power savings

  • Support next-generation capabilities and technologies

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SONET/SDH in ASIA

There are small numbers of operators in India, East Asia, and Europe who are
attempting to build networks without any SONET/SDH layer. The reason for small
number of operators is that the SONET'/SDH's installed base is too large for
carriers to simply walk away. The service providers are looking to buttress
private line profits by adding data private lines with enhanced management and
security. Major efforts for Ethernet over Optical networks have been done and
this restraints Ethernet over SONET.

Ethernet over SONET/SDH is limited point to point service today, It is
expected that for the carriers to takings they must shore up multiplexing and
multi point services. The data private line is part of incumbent carrier
strengths to support private line profits. The equipment vendors are expected to
develop systems that span from customers to core, leveraging advances in traffic
management, multiplexing services. It is expected that by replacing SONET/SDH
add/drop multiplexers (ADMs) with multi service platforms that support Ethernet
and other packet-based protocols, as well as TDM, carriers can achieve
significant returns on their scarce investment.

Key elements in Multi Service over SONET/SDH are:

  • Data optimization of the SONET/SDH transport layer

  • Quality of service (QoS) to achieve target service-level
    agreements

  • Opportunities in packet based services over SONET/SDH

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The major factors determining market growth of the world
SONET/SDH test equipment market include:

Drivers

  • User demand for Ethernet-based services is the major
    driver for this market.

  • High bandwidth requirement, along with the integrated
    product functionality (generic framing procedures and virtual concatenation)
    drive the world SONET/SDH test equipment market.

  • Movement towards optical and data convergence is also
    driving demand for SONET/SDH test equipment.

Restraints

  • End user spending condenses demand in the SONET/SDH test
    equipment market.

  • There is a slow adoption rate of next generation SONET/SDH
    test equipment as users are not willing to let go off their existing
    equipment and hence are not upgrading.

  • As there is not much technological development, sale in
    the new test equipment market is retarded.

Challenges

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  • The Slow capital expenditure (CAPEX) situation is
    dampening demand for SONET/SDH test equipment market.

  • The complexity of Next generation SONET/SDH test
    equipment poses a serious challenge to test vendors.

  • End user requirements challenging vendors of SONET/SDH
    test equipment in terms of product development. Quality of service is also
    representing a significant challenge for vendors.

Outlook

The SONET/SDH market experienced a downward spiral in the last few years.
However, the future looks positive. The price of this equipment is in parity
with asynchronous equipment and is expected to decline further. Next-generation
SONET/SDH technologies are main driver for the growth of SONET/SDH test
equipment market.

Key Market Participants

Key market participants include Agilent technologies Inc. (www.agilent.com)

Acterna (www.acterna.com)

Anritsu incorporation (www.anritsu.com)

EXFO (www.exfo.com)

Sunrise Telecom (www.sunrise.com)

Prathima Bommakanti
research analyst, Frost & Sullivan