Optical network architecture
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Optical networks use fiber optic technologies and components to transmit data at high speeds. They employ network architectures like synchronous optical networks (SONET) and passive optical networks (PONs) to route data through the core transport network and provide access to customers. SONET uses time-division multiplexing and self-healing ring topologies to interconnect equipment from different vendors. PONs have a star topology and use different wavelengths to transmit data downstream and upstream without electronic regeneration between transmitters and receivers.
Optical network architecture
- 1. Optical network architecture Presented by:- Siddharth Singh 1109131099
- 2. Optical Networks Optical networks are high-capacity telecommunications networks based on optical technologies and components that provide routing, grooming, and restoration at the wavelength level as well as wavelength-based services. Optical Fibre Transmission System Optical Fibre Transmission System electrical signal electrical signal optical signal
- 3. Optical Network Architecture • Network architecture: The general physical arrangement and operational characteristics of communicating equipment together with a common set of communication protocols • Optical Network enables carriers to deploy an optical service platform into regional and long haul core transport networks to maximize service flexibility simplify network operations.
- 4. Optical Network Architecture Metro Network Long Haul Network Metro Network Access Network Access Network Access Network Access Network transport network PON SONET DWDM Customer premise Customer premise Customer premise Customer premise
- 5. Synchronous Optical Networks • SONET is the TDM optical network standard for North America • SONET is called Synchronous Digital Hierarchy (SDH) in the rest of the world • SONET is the basic physical layer standard • Other data types such as ATM and IP can be transmitted over SONET. • Linear multiplexing and de-multiplexing is possible with Add-Drop-Multiplexers
- 6. SONET/SDH • The SONET/SDH standards enable the interconnection of fiber optic transmission equipment from various vendors through multiple-owner trunk networks. • The basic transmission bit rate of the basic SONET signal is Basic formats of (a) an STS-N SONET frame
- 7. • In SDH the basic transmission bit rate is 155.52 Mb/s. (b) an STM-N SDH frame
- 8. SONET/SDH Rings • SONET and SDH can be configured as either a ring or mesh architecture • SONET/SDH rings are self-healing rings because the traffic flowing along a certain path can be switched automatically to an alternate or standby path following failure or degradation of the link segment • Two popular SONET and SDH networks: – 2-fiber, unidirectional, path-switched ring (2-fiber UPSR) – 2-fiber or 4-fiber, bidirectional, line-switched ring (2-fiber or 4-fiber BLSR) Generic 2-fiber UPSR with a counter- rotating protection path
- 9. Generic SONET network Large National Backbone City-wide Local Area Versatile SONET equipment are available that support wide range of configurations, bit rates and protection schemes
- 10. Passive Optical Networks • In general, there is no O/E conversion between the transmitter and the receiver (one continuous light path) in PON networks • Only passive elements used to configure the network • Power budget and rise time calculations has to be done from end-to-end • There are star, bus, ring, mesh & tree topologies • Currently PON Access Networks are deployed widely and the word PON means mainly the access nw. The PON will still need higher layer protocols (Ethernet/IP etc.) to separate multiple users
- 12. Star, Tree & Bus Networks • Tree networks are widely deployed in the access front • Tree couplers are similar to star couplers (expansion in only one direction; no splitting in the uplink) • Bus networks are widely used in LANs • Ring networks (folded buses with protection) are widely used in MAN • Designing ring & bus networks is similar
- 13. Star Network Power Budget: Worst case power budget need to be satisfied Ps-Pr = 2lc + α(L1+L2) + Excess Loss + 10 Log N + System Margin
- 15. Passive Optical Networks (PONs) • A passive optical network (PON) uses CWDM over a single bidirectional optical fiber. • Only passive optical components guide traffic from the central office to the customer premises and back to the central office. – In the central office, combined data and digitized voice are sent downstream to customers by using a 1490-nm wavelength. – The upstream (customer to central office) uses a 1310-nm wavelength. – Video services are sent downstream using a 1550-nm wavelength.
- 16. Active PON Modules • The optical line termination (OLT) is located in a central office and controls the bidirectional flow of information across the network. • An optical network termination (ONT) is located directly at the customer premises. – The ONT provides an optical connection to the PON on the upstream side and to interface electrically to the local customer equipment. • An optical network unit (ONU) is similar to an ONT, but is located near the customer and is housed in an outdoor equipment shelter.
- 17. References IEEE Explore http://ieeexplore.ieee.org IEEE spectrum www.ieee-spectrum.org/ "SONET/SDH Technical Summary". TechFest. TechFest.com. 2002. Retrieved 2010-11-13 March 19, 2015 17