Network Analysts and Consultants
"We Have the Experience"
ViewsLetter on Provisioning
21 April 2003
TWO EXAMPLES SHOW INCREASING FLEXIBILITY
IN PROVISIONING AT THE PHYSICAL LAYER
--By William A. Flanagan, Editor and Publisher, ViewsLetter
Probably not by coincidence, both examples of provisioning flexibility
in optical nodes that rely on technology related to
Optical-Electrical-Optical (OEO) regeneration. Both allow software
configuration to set up the same physical port for a variety of bit rates,
formats, and services. Both target the "transmission" side of carriers
(and large enterprises) and do not position their products as data
ADVA Optical Networking ( www.advaoptical.com ) focuses on provisioning
point-to-point connections based on coarse and dense Wave Division
Multiplexing (WDM). ADVA's carrier customers generally offer a managed
network service for Fiber Channel, 10/100/1000 Ethernet (transparent LAN),
or dedicated wavelengths. There is a large node, the FSP2000, for
of presence serving multiple customers. A new, smaller model, "FSP3000
Slimline," serves one customer at 30% lower cost for the first wavelength.
The FSP platforms share several interesting features:
-- combining coarse and dense WDM, with cascaded optical multiplexers
(coarse to split out a band, then dense to divide the band).
-- passive pass-through of wavelengths not terminated at a node (adding
wavelengths requires additional muxes only at the end points of circuits,
not at intermediate nodes).
-- A choice of lasers, detectors, and full-band optical amplifiers to
reach 20 to 600 km between nodes.
A key ingredient to ADVA's flexibility is the transparency of the
electrical portion of each OEO regeneration. A same circuit can
at 10 Mbit/s or OC-12. By configuration, the manager can set a cap
speed, allowing a carrier to price circuits by value (speed) as well as
other factors. Being transparent, FSPs can be compatible with SONET
equipment (mid-span meet) and also carry Ethernet over Optical (EoO)
without SONET framing on the wavelength.
As Brian McCann, ADVA's Chief Marketing and Strategy Officer, put it,
"Carriers can sell a Storage Area Network or a SONET circuit the way they
Mahi Networks (www.mahinetworks.com ) gains flexibility from its unusual
core switching fabric based on a very fast, single-stage crossbar switch.
Similar (in concept only) to the old voice cross bar that set up a
metallic path when needed, Mahi's Xbar sets up a mulit-Gbit/s path between
input and output ports. The I/O cards buffer information, in whatever
format, for very short periods. A scheduler function controls the
when an input buffer is ready, it can send those bits in a burst over
very, very short period. Because the buffers and Xbar operate at
high speed, they introduce insignificant delay. As a result of the
latency, and regular attention from the scheduler, the mechanism works
well for TDM channels and any format as it does for packet traffic.
That compatibility with TDM lets Mahi nodes fit in with existing SONET
infrastructure. According to Christopher Rust, president and CEO,
have worked to fit into existing carrier networks, making our optical
devices look and act like a Digital Access and Crossconnect System to
current operations support systems--down to support for TL-1 configuration
language. However, by combining Add Drop Multiplexer and DACS functions,
we can support new optical interfaces defined by the OIF, including
signaling for Generalized Multiprotocol Label Switching. In fact,
could be the SS7 of packet networks, down to the optical level."
Both companies point to total cost savings or life time cost reductions.
There is some reduction in capital expense (30% to 60%), which is
important although hardware is only a fraction of the lifetime cost of
network. The big savings come from operating expense reductions--adding
new customers or changing a circuit requires far less involvement by craft
people. An estimate for one RBOC, showed savings of $9 million at
300 central offices (out of 1600 COs), or $2.7 billion, for deployment
an OC-48 network. Mahi says a new OC-3 in the metro takes only one day,
leading to OpEx savings calculated by one carrier at $24 million over
"Savings" to one party in a transaction often means "loss" to another.
network building a zero-sum game where somebody always loses? Or
a way to benefit everyone in the industry? Being optimists, some
expect benefits of automated provisioning to shower on everyone.
you think? Who else gains? Who might lose? Write to
your comments: mailto:firstname.lastname@example.org
"Flanagan Consulting" and "ViewsLetter" are
Service Marks of W. A. Flanagan, Inc.
Updated: 11 June 2003