SNCP vs MSP

MSP(Multiplex Section Protection) is a per span protection.

A service line is protected using another line, called a protection line. If an error occurs, the protection mechanism should switch over to the protection line. There are two main protection schemes for the multiplex section:
• 1+1 : Traffic is simultaneously transmitted over working and protecting lines (or cards if it is for hiT i.e. MSP bridge). The incoming traffic is select from the line that delivers signal in best condition (specifically switch fabric selector is responsible for making the selection in a HiT).
o Switching type: unidirectional or bi-directional
o Operation type: revertive or non-revertive


• 1:N : A 1:N multiplex section protection system consists of N traffic-carrying multiplex sections that are to be protected by an additional multiplex section. In this scheme only one of the working sections can be protect at a time. The additional multiplex section can be used to carry low-priority traffic (unprotected) when it is not used as a protection section for the rest N working sections.
o 1:N with N<=14 for STM-1/4/16 and N<=7 for STM-16/64
o Switching type: bi-directional
o Operation type: revertive


• 1:1 : This is a special case of 1:N protection scheme. In case of a failure on the working path, traffic is switched to protecting path.
o Switching type: bi-directional
o Operation type: revertive

SubNetwork Connection Protection. is a per path protection.

SNCP is a network protection mechanism for SDH networks providing path protection (end-to-end protection). The data signal is transmitted in a ring structure via two different paths and can be implemented in line or ring structures. The changeover criteria are specified individually when configuring a network element. A protection protocol is not required. The switchover to protection path occurs in the non-revertive mode, i.e. if traffic was switched to the protection path due to a transmission fault, there is no automatic switch-back to the original path once the fault is rectified, but only if there is a fault on the new path (the one labeled as “protecting” and currently services traffic).

SNCP is a 1+1 protection scheme (one working and one protection transport entity). Input traffic is broadcasted in two routes (one being the normal working route and the second one being the protection route).

Assume a failure free state for a path from a node B to a node A. Node B bridges the signal destined to A from other nodes on the ring, both on working and protecting routes. At node A, signals from these two routes are continuously monitored for path layer defects and the better quality signal is selected.
Now consider a failure state where fiber between node A and node B is cut. The selector switches traffic on the standby route when the active route between node A and node B is failed.

In order to prevent any unnecessary or spurious protection switching in the presence of bit errors on both paths, a switch will typically occur when the quality of the alternate path exceeds that of the current working path by some threshold (e.g., an order of magnitude better BER). Consecutively, any case of failure drops in SNCP’s decision mechanism.

Synchronous optical networking

Synchronous Optical Networking (SONET) and Synchronous Digital Hierarchy (SDH) are standardized multiplexing protocols that transfer multiple digital bit streams over optical fiber using lasers or light-emitting diodes (LEDs). Lower data rates can also be transferred via an electrical interface. The method was developed to replace the Plesiochronous Digital Hierarchy (PDH) system for transporting larger amounts of telephone calls and data traffic over the same fiber without synchronization problems. SONET generic criteria are detailed in Telcordia Technologies Generic Requirements document GR-253-CORE.
Generic criteria applicable to SONET and other transmission systems (e.g., asynchronous fiber optic systems or digital radio systems) are found in Telcordia GR-499-CORE.
SONET and SDH, which are essentially the same, were originally designed to transport circuit mode communications (e.g., DS1, DS3) from a variety of different sources, but they were primarily designed to support real-time, uncompressed, circuit-switched voice encoded in PCM format.
The primary difficulty in doing this prior to SONET/SDH was that the synchronization sources of these various circuits were different. This meant that each circuit was actually operating at a slightly different rate and with different phase. SONET/SDH allowed for the simultaneous transport of many different circuits of differing origin within a single framing protocol. SONET/SDH is not itself a communications protocol per se, but a transport protocol.
Due to SONET/SDH's essential protocol neutrality and transport-oriented features, SONET/SDH was the obvious choice for transporting Asynchronous Transfer Mode (ATM) frames. It quickly evolved mapping structures and concatenated payload containers to transport ATM connections. In other words, for ATM (and eventually other protocols such as Ethernet), the internal complex structure previously used to transport circuit-oriented connections was removed and replaced with a large and concatenated frame (such as OC-3c) into which ATM cells, IP packets, or Ethernet frames are placed.


Racks of Alcatel STM-16 SDH add-drop multiplexers
Both SDH and SONET are widely used today: SONET in the United States and Canada, and SDH in the rest of the world. Although the SONET standards were developed before SDH, it is considered a variation of SDH because of SDH's greater worldwide market penetration.
The SDH standard was originally defined by the European Telecommunications Standards Institute (ETSI), and is formalized as International Telecommunications Union (ITU) standards G.707,[4] G.783,[5] G.784,[6] and G.803.[7][8] The SONET standard was defined by Telcordia[1] and American National Standards Institute (ANSI) standard T1.105.

Synchronous networking differs from Plesiochronous Digital Hierarchy (PDH) in that the exact rates that are used to transport the data on SONET/SDH are tightly synchronized across the entire network, using atomic clocks. This synchronization system allows entire inter-country networks to operate synchronously, greatly reducing the amount of buffering required between elements in the network.
Both SONET and SDH can be used to encapsulate earlier digital transmission standards, such as the PDH standard, or they can be used to directly support either Asynchronous Transfer Mode (ATM) or so-called packet over SONET/SDH (POS) networking. As such, it is inaccurate to think of SDH or SONET as communications protocols in and of themselves; they are generic, all-purpose transport containers for moving both voice and data. The basic format of a SONET/SDH signal allows it to carry many different services in its virtual container (VC), because it is bandwidth-flexible.

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BIOMETRIC RECOGNISATION

Iris Recognition System Matlab Source Code. The iris of each eye is unique. No two irises are alike in their mathematical detail--even between identical twins and triplets or between one's own left and right eyes. Unlike the retina, however, it is clearly visible from a distance, allowing easy image acquisition without intrusion. The iris remains stable throughout one's lifetime, barring rare disease or trauma. The random patterns of the iris are the equivalent of a complex human barcode, created by a tangled meshwork of connective tissue and other visible features. The iris recognition process begins with video-based image acquisition that locates the eye and iris. Matlab Image Processing Toolbox is required.

MICROPHOTONICS

Microphotonics is a branch of technology that deals with directing light on a microscopic scale. It is used in optical networking.

Microphotonics employs at least two different materials with a large differential index of refraction to squeeze the light down to a small size. Generally speaking virtually all of microphotonics relies on Fresnel reflection to guide the light. If the photons reside mainly in the higher index material, the confinement is due to total internal reflection. If the confinement is due many distributed Fresnel reflections, the device is termed a photonic crystal. There are many different types of geometries used in microphotonics including optical waveguides, optical microcavities, and Arrayed Waveguide Gratings.