AT&T will buy lambda routing/switching equipment sometime this year from Lucent, Nortel or Ciena.
nwfusion.com
AT&T heads down optical net path
Company says new platform will enable bandwidth on demand.
By DENISE PAPPALARDO
Network World, 03/07/01
AT&T is aggressively moving toward an all-optical
network to create a faster IP backbone capable of
delivering bandwidth on demand.
AT&T is progressing toward its all-optical goal by
testing Lambda routers, building network management
software and looking to strike deals with metropolitan
Gigabit Ethernet service providers. While AT&T will
not say how much it is investing in this effort, it
indicates the transformation to an all-optical network
will take three or more years.
It could be 18 months before bandwidth-on-demand
services are widely available from AT&T, although it's
likely the carrier will strike deals with Gigabit Ethernet
metropolitan service providers to deliver local
wavelength services much sooner.
The carrier will start testing Lambda routers from two
vendors by year-end, letting the carrier switch
individual wavelengths of light onto separate routes,
says Hossein Eslambolchi, an AT&T senior vice
president. While the carrier will not say which
vendors' products it will test, analysts speculate they
will be from Lucent, Nortel Networks or Cienna.
AT&T will use Lambda routing in conjunction with
dense wave division multiplexing (DWDM)
technology, which lets carriers boost network
capacity by sending more wavelengths over each fiber
strand. AT&T has DWDM equipment in its network
that supports 80 channels per fiber strand, but
Eslambolchi says the carrier will upgrade to 160
channels per fiber strand later this year and will
eventually upgrade to 320 channels per strand.
The combination of Lambda routing and DWDM is
designed to provide users with two key service
features: bandwidth on demand and shorter waits for
service provisioning.
"OC-48 [2.4G bit/sec] connections take months to
provision," Eslambolchi says. A 2.4G bit/sec
wavelength will take minutes to turn on, he says.
AT&T isn't the only carrier testing Lambda or
wavelength routers, says Lisa Pierce, an analyst at
Giga Information Group.
"WorldCom has been playing with Lambda routing in
its lab for about a year now," she says (Switch
architecture changes on WorldCom agenda).
Broadwing Communications and Global Crossing are
also going in this direction, a strategy simplified
because neither has as big a U.S. customer base or
network to deal with as its larger rivals, says Maribel
Dolinov, a senior analyst at Forrester Research.
"Lambda routing has great potential in the backbone,"
Pierce says. But she says carriers have to guarantee
this new network architecture is going to be as reliable
as SONET, the predominant network technology in
legacy carrier networks.
Most carriers can restore a failed SONET ring within
60 milliseconds. AT&T's Eslambolchi says it has been
a challenge to develop management tools that will
make an all-optical network just as reliable. Part of
the challenge is that AT&T is moving away from a
ring architecture to a fully meshed system.
AT&T's SONET network primarily operates at
OC-48, although it features a coast-to-coast OC-192
(10G bit/sec) span. While a mesh architecture offers
more flexibility for routing traffic, it also complicates
network restoral.
"We have developed an algorithm to guarantee
restoration in a mesh environment," Eslambolchi says.
This type of software is not yet available from
vendors, he says. |
