|
Guest Column
GMPLS
– the New Big Deal in Intelligent
Metro Optical Networking
By
Sab Gosal
Director of Product Marketing
Polaris Networks Inc.
May
20, 2002
Introduction
Over
the last 18 months the telecom industry has witnessed
a dramatic
change. With service providers focused on increasing revenues
and services more than ever before, the metro network has
taken center stage. Functioning as the critical bridge between
the access and long-haul network segments, metro networks are
faced with the challenge of having to adapt to the new
requirements of service providers: "bandwidth on
demand, not to forecast." This paradigm shift has
created the need to migrate today’s complex overlay metro
network to a new, highly scalable architecture that is simple
yet enables rapid service provisioning, dynamic bandwidth
management and flexible service creation. One viable solution
for this challenge is to unify all the different services
under a common control plane and automate network resources
using Generalized Multi-protocol Label Switching (GMPLS).
Specified
by the International Engineering Task Force (IETF), GMPLS is a
new protocol suite that uses advanced network signaling and
routing mechanisms to automate set up for end-to-end
connections for all types of network traffic (TDM,
packet/cell, wavebands and wavelengths). The metro optical
network, given its need to support a diverse range of services
using a variety of transport technologies, is an ideal
candidate for GMPLS-based control and provisioning. A GMPLS
metro network can offer many capabilities that include:
- Network
resource discovery and routing control
- Dynamic
provisioning and traffic engineering for end-to-end
connections
- Bandwidth
on demand for just in time service creation
- New
quality of service (QoS)-defined value added services
- New
granularities in service restoration and protection
Evolution
of GMPLS
GMPLS has evolved from MPLS -
the original IETF standard intended to enhance the forwarding
performance and traffic engineering intelligence of
packet-based (ATM, IP) networks. GMPLS extends these switch
capabilities so that it is not only packet switch capable (PSC),
but also Time Division Multiplex capable (TDM), Fiber Switch
Capable (FSC) and Lambda Switch Capable (LSC). Therefore
unlike MPLS, which is supported mainly by routers and data
switches, GMPLS can be supported by a variety of optical
platforms including SONET ADMs, Optical Cross-connects (OXCs)
and DWDM systems. This will allow an entire infrastructure,
extending from the access network to the core network to
utilize a common control plan. Table 1 summarizes the
characteristics of GMPLS.
| Switching
Domain |
Traffic
type |
Forwarding
Scheme |
Example
of Device |
Nomen-
clature |
| Packet,
cell |
IP,
ATM |
Label
as Shim Header, VCC |
IP
router, ATM switch |
Packet
Switch Capable (PSC) |
| Time |
STS-/SONET |
Time
slot in repeating cycle |
Digital
Cross-connect System (DCS); Add/Drop Multiplexers (ADM) |
TDM
capable (TDM) |
| Wavelength |
Transparent |
Lambda |
Dense
Wave Division Multiplexer (DWDM) |
Lambda
Switch Capable (LSC) |
| Physical
space |
Transparent |
Fiber,
line |
Optical
Cross-connect (OXC) |
Fiber
Switch Capable (FSC) |
See a larger
version of this Table
Table
1. GMPLS Characteristics
Next
page >>
Page 1 of 5
|
