Special Report: Next Generation Internet Applications
Multiprotocol Lambda Switching (MP S) Multiprotocol Lambda Switching
(MP'S) is the optical equivalent of Multiprotocol Label Switching (MPLS).
MPLS was designed to provide high- speed packet switching in the electronic
domain. Implemented on the core routers within a network as shown in Figure
20, MPLS provides a mapping of Layer 3 traffic to Layer 2 transports, in
an effort to reduce the processing overhead of current packet-switched networks.[22]
MPLS achieves high-speed switching by adding a fixed-length 4-octet field
to the IP packet. High-speed hardware segments the label, reads the QoS
flags, and directs the data flow without the need for inspecting the remainder
of the packet header or calculating the data flow path. The MPLS label is
appended at the edge gateway of the network. Each MPLS router along the
path reads the encapsulation label and immediately forwards the packet towards
its destination without further inspection. If necessary, the label could
be modified by an inner MPLS router for optimized dataflow redirection.
This label is finally removed by the destination gateway to produce the
original packet. MPLS is highly scalable, since all of the necessary direction
information can be obtained from the label and no reference has to be made
to large tables located at each router. Label added by edge router and inspected
by core routers. MP'S extends the MPLS concept directly into the optical
domain as shown in Figure 21. Optical interconnects can be controlled to
route traffic on specific wavelengths, through the optical network core,
to the destination edge optical gateway. MP'S operates on specific wavelengths
in much the same manner that MPLS operated on packet switched data. Implementation
requires the use of a control plane to accomplish the traffic engineering
and subsequent traffic redirection. Implemented with either an overlay control
plane or peer control plane, MP'S provides control of the optical physical
layer providing DWDM-level network provisioning. Adding controllability
to the switching of wavelengths provides network engineers with the ability
to dynamically allocate the available core bandwidth. The bandwidth provisioning
speed is also increased because the QoS is implemented on a per-wavelength
basis as opposed to a per-packet basis. Through advanced traffic class segregation
and aggregation, core level QoS can be optimized.
MP'S is gaining standards support, but is still several years from widespread
implementation. The Internet Engineering Task Force (IETF), International
Telecommunication Union - Telecommunication Standardization Sector (ITU-T),
Optical Internetworking Forum (OIF), and American National Standards Institute
(ANSI) are all investigating dynamically reconfigurable optical networks
such as MP'S.[24] Optical networks are on the verge of revolutionizing the
way we communicate, and MP'S could be the control mechanism to make it a
reality. Photonic Network Architecture: Next Generation Internet Applications
3.0 NETWORK TECHNOLOGY IN TRANSITION For the past one hundred years, communications
technology has evolved along service cycles. A service cycle begins when
a new service is introduced. The service progresses through the cycle, gaining
popularity and becoming the dominant contributor to new network revenue
and capacity demand. At maturity, network operators satisfy demand for the
service, network growth subsides, and revenues level off. The next service
cycle begins when a new service upstages the mature service by creating
new network revenue and dominating network growth. The service cycles for
telegraph, telex, and telephone spanned decades. As time passed, the service
cycles became progressively shorter. Each cycle saw the market for interpersonal
communications move to a new network growth leader. Telex upstaged telegraph,
telephony superseded telex, and the Internet overshadowed telephony. Looking
ahead in time, multimedia messaging in the form of voice-over-IP, desktop
conferencing, and multimedia-on- demand may eventually surpass email and
html as the fastest growing method for interpersonal communications.
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