SSB:WCG Believes Mesh Architectures Are Great
Equipment Perspectives From The WCG Analyst Day Part II
Excerpts from SSB 2/13/01:
Williams Communications Group provided a tutorial session on network
technology as well as an overview of their business lines during their annual
analysts meeting. We believe that the meetings provided interesting insights
about their view of the evolution of networking technologies while providing
some counterpoints to commentary made by their competitor Level 3
Communications during their analysts meeting presentation. In terms of mesh
architectures, for example, they affirmed that meshes were of great utility,
improving overall network cost economics. While on initial glance this seems
to conflict with commentary from Level 3's analysts meeting, actually it
really does not. In Level 3's case, they are referencing the implementation
of an electronic mesh network (O-E-O) with incremental equipment expenses
necessary to ramp capacity. The incremental costs of the electronic
equipment offsets the efficiency benefits of the mesh architecture. In
Williams case, they are deploying an all-optical mesh, where those
unfavorable cost dynamics are not present.
Williams Seems To Embrace An Optronics, Relative To A Fiber Based Focus,
Within Their Network. Williams argued that the innovation cycles within the
optronics were much more rapid and incremental than those in fiber. They
cited that the cost of providing OC-192 connectivity has fallen 90% over the
last couple of years due primarily to optronics, not fiber. Furthermore,
they believed that the next quantum shift in fiber technology is likely 2-3
years away with the introduction of soliton technology in fiber. In this
technology, offsetting dispersion and compression forces maintain the shape
of an optical signal as it propagates along the fiber, reducing the need for
frequent regeneration.
The carrier repeatedly referenced the 70 km (40 mile) spacing of amplifiers
within their network, relative to the 100 km (60 mile) spacing of competitors
such as Level 3. They argued that this made their networks more leveraged to
the improvements in optronics, particularly within the ultra-long haul area.
They explained that when deploying Corvis technology, for example, they can
garner a 50% improvement in network economics due to this closer amplifier
spacing relative to what other carriers employing Corvis can enjoy.
Furthermore, the believe that their need to light additional fiber is likely
to be less than comparable carriers, given the same amount of network
traffic. They believe that the closer amp spacing should allow them employ
denser DWDM systems, reducing the need to light additional fiber strands.
This orientation contrasts with Level 3 which designed its network to be more
skewed toward fiber innovation cycles, by its decision to employ numerous
empty conduits in order to run new generations of fiber.
Williams Believes Mesh Architectures Are Great In The Right Place. When asked
about mesh architectures, Williams management commented that these structures
were clearly superior within the network core but of more limited utility
within the metro segment. In their view, mesh architectures work best where
there are numerous network crosspoints, which tends to occur within the
core. Conversely, within the metro there are usually only one, or maybe two
rings.
Williams Believes Mesh Architectures Are Great In The Right Place. When asked
about mesh architectures, Williams management commented that these structures
were clearly superior within the network core but of more limited utility
within the metro segment. In their view, mesh architectures work best where
there are numerous network crosspoints, which tends to occur within the
core. Conversely, within the metro there are usually only one, or maybe two
rings.
Notwithstanding these limitations, Williams commented that meshes were quite
useful in the core of the network. SONET rings are only 50% efficient in
theory given there is 100% network redundancy in order to provide restoration
capabilities. Management believed, however, that the practical efficiency in
a real-time environment was only 38%. Conversely, Williams asserted that
the theoretical efficiency of mesh infrastructures are 75%, with the
pragmatic efficiencies in the 65% range. Management also commented that mesh
structures provide more flexibility in terms of QoS structures, allowing
carriers to provide differentiated services that can address different
customer sets. Within a mesh, a carrier can offer APS or Automatic
Protection Switching which is SONET ring-like protection. In addition, other
restoration options such as preemptive mesh and unprotected transport.
Another point that we gained in our commentary with management was the degree
of difficulty in building an effective mesh networks. In order to garner the
promised efficiency benefits from mesh, its critical to make a number of key
network design decisions. In addition, limited interoperability issues are
impacting the attractiveness of some vendors equipment, inhibiting their mesh
capabilities.
It should be noted that recently Level 3 made comments regarding the lack of
attractiveness of mesh architectures, asserting that the technology was
immature and of limited economic benefit today. It should be noted that
comparing the statements of the two carriers is analogous to comparing apples
to oranges. Level 3 was refering to implementing an electronic mesh
architecture, where the carrier must bear incremental electronic costs to
ramp the capacity of the network, such as inputing line cards within O-E-O
switches throughout the network. Conversely, Williams is implementing an
all-optical mesh (O-O-O), where those incremental electronic costs are
avoided, enhancing the network economics of the architecture. |
