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By B.A. Khivsara Asst. Prof In Computer Dept SNJB’s KBJ COE ,Chandwad
Computer Networks
Unit -6
Advance Network Technologies
Chapter Outline
Virtualization
Software defined network
ATM(Overview, Protocol Architecture, AAL)
GMPLS
Introduction of optical networks,
Propagation of Signals in Optical Fiber
Client Layers of the Optical Layer
What is meant by virtualization
In computing, virtualization means to create a virtual version of a device or resource, such as a server, storage device, network or even an operating system where the framework divides the resource into one or more execution environments.
Even something as simple as partitioning a hard drive is considered virtualization because you take one drive and partition it to create two separate hard drives.
Virtualization in networking
When applied to a network, virtualization creates a logical software-based view of the hardware and software networking resources (switches, routers)
The physical networking devices are simply responsible for the forwarding of packets.
While the virtual network (software) provides an intelligent abstraction that makes it easy to deploy and manage network services and underlying network resources.
Virtualization in networking
Network Virtualization allows for abstracting the Networking resources into a logical/software model so that the same set of physical resources can be shared by multiple occupants in a protected and isolated manner.
There are 2 kinds of Networking resources, one is the physical resources like Router, Switch and
another is appliances like Firewall, Load balancer etc. The appliance can be either physical or virtual.
Elements of network virtualization?
Network virtualization can be implemented at the server or cluster level using hypervisor software
You can create a virtual network on a single system.
The hypervisor provides the abstraction layer that allows different types of internal networks to mimic the physical world.
Advantages of Virtualization in Networking
1. Easy and cheaper to manage networks: With network virtualization you can manage your network devices through a single management console. You don’t need physical access to switches, varied skills sets to manage multiple switches and routers,.
2. Reduce time to provision: It helps you to deploy your applications in a much quicker time.
3. Avoids limitations in current network topologies
4. Ease of building a fully automated cloud environment
5. Allows for policy based access
6. Analytics and easier troubleshooting
7. Cut down the cost to purchase core switches and routers.
Chapter Outline
Virtualization
Software defined network (SDN)
ATM(Overview, Protocol Architecture, AAL)
GMPLS
Introduction of optical networks,
Propagation of Signals in Optical Fiber
Client Layers of the Optical Layer
SDN Architecture
SDN Concept
Software-defined networking (SDN) is an approach to computer networking that allows network administrators to manage network services through abstraction of higher-level functionality.
This is done by decoupling the system that makes decisions about where traffic is sent (the control plane) from the underlying systems that forward traffic to the selected destination (the data plane).
SDN requires some method for the control plane to communicate with the data plane. One such mechanism is OpenFlow.
SDN Concept
Separate Control plane and Data plane entities
• Network intelligence and state are logically centralized
• The underlying network infrastructure is abstracted from the applications
Execute or run Control plane software on general purpose hardware
• Decouple from specific networking hardware
• Use commodity servers
Have programmable data planes
• Maintain, control and program data plane state from a central entity
An architecture to control not just a networking device but an entire network
SDN Benefits
Dynamic , Manageable ,cost-effective, adaptable
Directly programmable
Agile: administrators dynamically adjust network-wide traffic flow to meet changing needs.
Centrally managed
Programmatically configured: SDN lets network managers configure, manage, secure, and optimize network resources very quickly via dynamic, automated SDN programs
Open standards-based and vendor-neutral
Chapter Outline
Virtualization
Software defined network
ATM(Overview, Protocol Architecture, AAL)
GMPLS
Introduction of optical networks,
Propagation of Signals in Optical Fiber
Client Layers of the Optical Layer
ATM: Asynchronous Transfer Mode
Overview
Protocol Architecture
AAL
ATM-Asynchronous Transfer Mode
ATM is the cell relay protocol designed by ATM forum and adopted by ITU-T
ATM uses asynchronous TDM
Cells are transmitted along virtual circuits
Design Goals
• Large bandwidth and less susceptible to noise degradation
• Interface with existing systems without lowering their effectiveness
• Inexpensive implementation
• Support the existing telecommunications hierarchies
• Connection-oriented to ensure accurate and predictable delivery
• Many functions are hardware implementable
Multiplexing using Cells
• A cell network uses the cell as the basic unit of data exchange
– A cell is defined as a small, fixed sized block of information
– Cells are interleaved so that non suffers a long delay
– A cell network can handle real-time transmissions
– Network operation is more efficient and cheaper
Computer Networks 18-17
ATM Conceptual Model
ATM network will be organized as a hierarchy.
• User’s equipment connects to networks via a UNI (User-Network Interface).
• Connections between provided networks are made through NNI (Network-Network Interface).
ATM will be connection-oriented.
• A connection (an ATM channel) must be established before any cells are sent.
Networks: ATM 18
ATM Connections
• virtual path connections
• virtual channel connections
Two levels of ATM
connections:
• virtual path identifier VPI
• virtual channel identifier VCI
Indicated by two fields in
the cell header:
Networks: ATM 19
ATM Architecture
• UNI: user-to-network interface
• NNI: network-to-network interface
Computer Networks 18-20
Virtual Connection • Connection between two endpoints is accomplished through
– Transmission path (TP)
– Virtual path (VP)
– Virtual circuit (VC)
• A virtual connection is defined by a pair of numbers: VPI and VCI
Computer Networks 18-21
VPI and VCI: Hierarchical Switching
Computer Networks 18-22
Identifiers and Cells
Computer Networks 18-23
ATM Layer and Headers
Computer Networks 18-24
ATM: Asynchronous Transfer Mode Overview
Protocol Architecture
AAL
Networks: ATM 26
Plan
e man
agemen
t
Management plane
Control plane User plane
Physical layer
ATM layer
ATM adaptation layer
Higher layers Higher layers
Layer man
ageme
nt
Figure 9.2 Leon-Garcia & Widjaja: Communication Networks Copyright ©2000 The McGraw Hill Companies
ATM Layers
Computer Networks 18-27
ATM PHYSICAL LAYER The functions of this layer are split into two sublayers
• HEC generation and verification
• Cell scrambling and descrambling
• Cell delineation
• Path signal indication
• Time phasing-pointer processing
• Multiplexing
• Scrambling/descrambling
• Transmission frame generation/recovery
Transmission Convergence
TC
• Bit timing, line coding
• Physical medium
Physical Media Dependent
(PMD)
ATM LAYER
The ATM layer provides the following services:
Cell transmission : generation, reception, validation
Cell multiplexing/demultiplexing, cell relaying, cell copying
Cell payload discrimination Support of multiple QOS classes
Traffic management: usage control, traffic shaping, congestion notification
Connection assignment and removal
Switching
ATM Adaptation Layer (AAL)
The protocol for packaging data into cells is collectively referred to as AAL.
The ATM Adaptation Layer (AAL) is responsible for the conversion between user's data and ATM cells
Must efficiently package higher level data such as voice samples, video frames and datagram packets into a series of cells.
Networks: ATM 30
ATM: Asynchronous Transfer Mode Overview
Protocol Architecture
AAL
ATM Adaptation Layer (AAL) An AAL is further divided into:
Networks: ATM 32
The Convergence Sublayer (CS)
manages the flow of data to and from SAR sublayer.
(Responsible for Data integration)
The Segmentation and Reassembly Sublayer
(SAR)
breaks data into cells at the sender and reassembles
cells into larger data units at the receiver.
Application Adaptation Layer (AAL)
Convert data from upper-layer into 48-byte data units for the ATM cells
AAL1 – constant bit rate (CBR) video and voice
AAL2 – variable bit rate (VBR) stream low-bit-rate traffic an short-frame traffic such as audio
(ex: mobile phone)
AAL3/4 – connection-oriented/connectionless data
AAL5 – SEAL (Simple and Efficient Adaptation Layer)- No sequencing and error control mechanisms
Computer Networks 18-33
AAL1
Computer Networks 18-34
AAL2
Computer Networks 18-35
AAL3/4
Computer Networks 18-36
AAL5
Computer Networks 18-37
Chapter Outline
Virtualization
Software defined network
ATM(Overview, Protocol Architecture, AAL)
GMPLS
Introduction of optical networks,
Propagation of Signals in Optical Fiber
Client Layers of the Optical Layer
GMPLS Outline
Part I: MPLS
Part II: GMPLS
MPLS
MPLS stands for: “Multi-Protocol Label Switching”
Packets are switched, not routed, based on labels
Labels are filled in the packet header
Basic operation:
• Ingress LER (Label Edge Router) pushes a label in front of the IP header
• LSR (Label Switch Router) does label swapping
• Egress LER removes the label
MPLS Basic Idea
MPLS allows most packets to be forwarded at Layer 2 rather than having to be passed up to Layer
Each packet gets labeled on entry network by the ingress router.
All the subsequent routing switches perform packet forwarding based only on those.
Finally, the egress router removes the label(s) and forwards the original IP packet toward its final destination.
MPLS Basic Idea(Cont.)
The label determines which pre-determined path the packet will follow.
Service providers can use MPLS to improve quality of service (QoS) by defining latency, jitter, packet loss and downtime.
it works with the Internet Protocol (IP), Asynchronous Transport Mode (ATM), and frame relay network protocols
• MPLS involves setting up a specific path for a given sequence of packets by labeling every packet so that a routing table does not have to be referred in order to figure out which outward path a packet should be switched toward its destination. MPLS is called multiprotocol because it works with the Internet Protocol (IP), Asynchronous Transport Mode (ATM), and frame relay network protocols. In addition to moving traffic faster, MPLS makes it easier to manage a network for quality of service (QoS). The use of MPLS has become widespread as networks carry increasing volumes and varieties of traffic such as Voice over IP (VoIP).
MPLS Operation
Part II: GMPLS
GMPLS and MPLS
GMPLS is deployed from MPLS
• Apply MPLS control plane techniques to optical switches and IP routing algorithms to manage light paths in an optical network
GMPLS made some modifications on MPLS
• Separation of signaling and data channel
• Support more types of control interface
• Other enhancement
GMPLS Basics
GMPLS (Generalized Multiprotocol Label Switching), also known as Multiprotocol Lambda Switching,
is a technology that provides enhancements to Multiprotocol Label Switching (MPLS)
support network switching for time, wavelength, and space switching as well as for packet switching.
GMPLS Basics
Generalized Multiprotocol Label Switching (GMPLS) enhances MPLS architecture by the complete separation of the control and data planes.
GMPLS enables a seamless interconnection and convergence of new and legacy networks.
GMPLS is based on the IP routing and addressing models.
Why GMPLS?
While the technology used by the GMPLS control plane remains IP-based, the data plane (traffic plane) can now diversify to include more varieties of traffic like:
• Support multiple types of traffic (ATM, IP, SONET and etc.)
• Support both peer and overlay models
• Support multi-vendors
• Perform fast provisioning
Why GMPLS?
GMPLS is conceptually similar to MPLS, but instead of using an explicit label to distinguish an LSP at each LSR, some physical property of the received data stream is used
The most commonly used schemes are:
• using the timeslot to identify the LSP, on a Time Division Multiplexed (TDM) link
• using the wavelength to identify the LSP, on a Wavelength Division Multiplexed (WDM) link
• using the fiber or port on which a packet is received.
GMPLS Labels
GMPLS Control interfaces
Packet Switch Capable (PSC)
• Router/ATM Switch/Frame Reply Switch
Time Division Multiplexing Capable (TDMC)
• SONET/SDH ADM/Digital Crossconnects
Lambda Switch Capable (LSC)
• All Optical ADM or Optical Crossconnects (OXC)
Fiber-Switch Capable (FSC)
FSC
LSC
LSC
TDMC
TDMC
PSC
GMPLS Control Plane Functions and Services
Routing control—Provides the routing capability, traffic engineering, and topology discovery
Resource discovery—A mechanism to keep track of the system resource availability such as bandwidth, multiplexing capability, and ports
Connection management— connection creation, modification and deletion
Connection restoration—Implements an additional level of protection by establishing backup paths and enabling very fast switching in case of failure.
Chapter Outline
Virtualization
Software defined network
ATM(Overview, Protocol Architecture, AAL)
GMPLS
Introduction of optical networks,
Propagation of Signals in Optical Fiber
Client Layers of the Optical Layer
Optical Communication Systems
Communication systems with light as the carrier and optical fiber as communication medium
Optical fiber is used to contain and guide light waves
• Typically made of glass or plastic
Optical Fiber: Advantages
Capacity: much wider bandwidth (10 GHz)
Crosstalk immunity
Immunity to static interference
Higher environment immunity
Weather, temperature, etc.
Safety: Fiber is non-metalic:No explosion
Longer lasting
Security: tapping is difficult
Economics: Fewer repeaters
Disadvantages
Higher initial cost in installation
Interfacing cost
More expensive to repair/maintain
• Tools: Specialized and sophisticated
Optical Fiber Architecture
Transmitter
Input
Signal Converter Light
Source
Source-to-Fiber
Interface
Fiber-to-light
Interface
Light
Detector Decoder Output
Fiber-optic Cable
Receiver
Optical Fiber Architecture Components
• LED (Light Emitting Diode)
• ILD (Injection Laser Diode)
Light source:
• PIN (p-type-intrinsic-n-type)
• Photo Detector
• Both convert light energy into current
Light detector:
Optical Fiber Construction
Core – thin glass center of the fiber where light travels.
Cladding – outer optical material surrounding the core
Buffer Coating – plastic coating that protects the fiber.
61
About Light Rays (Angle of Reflection)
n2
aout
Glass material
with slightly
lower density
ain Glass material
with slightly
higher density
n1
a2 a2
a1 90
refraction Total
refraction reflection
Plane of Interface
Types Of Optical Fiber
62
Optical fiber
Step Index (SI) Graded Index (GI)
Single mode (SM) Multi mode (MM) Multi mode (MM)
Types Of Optical Fiber
Single-mode step-index Fiber
Multimode step-index Fiber
Multimode grade-index Fiber
Light
ray
Optical Fiber network uses Wavelength-Division Multiplexing
WDM sends information through a single optical Fiber using lights of different wavelengths simultaneously.
Laser
Optical sources
l1
l2
ln
ln-1
l3
l1
l2
ln
ln-1
l3
Laser
Optical detectors
Optical
amplifier
Multiplexer Demultiplexer
Application
Telecommunications
Local Area Networks
Cable TV
CCTV
Optical Fiber Sensors
Chapter Outline
Virtualization
Software defined network
ATM(Overview, Protocol Architecture, AAL)
GMPLS
Introduction of optical networks,
Propagation of Signals in Optical Fiber
Client Layers of the Optical Layer
Client Layers of the Optical Layer Outline
SONET/SDH
Optical Transport Network(OTN)
Ethernet (Gigabit)
Generic Framing Procedure(GFC)
IP
Multi Protocol Label Switching(MPLS)
Resilience packet ring (RPR)
Storage Area Network(SAN)
Client Layers of the Optical Layer
The network that use optical fiber as their underlying transmission mechanism.
These network are called as Client Layers of the Optical Layer.
All client layer that we discussed here perform time division multiplexing.
Client N/w are divided into two types
• Backbone N/W
• Metro N/W
Client Layers of the Optical Layer
• a. Synchronous Optical Network (SONET)/
• Synchronous Digital Hierarchy (SDH)
• b. Optical Transport Network(OTN)
• c. Generic Framing Procedure(GFP)
• d. Internet Protocol (IP)
• e. Asynchronous Transfer Mode (ATM)
• f. Multiprotocol Label Switching (MPLS)
In the backbone networks
• a. Gigabit Ethernet
• b. 10-Gigabit Ethernet
• c. Fiber channel
• d. Resilient Packet Ring (RPR)
In the metro
networks 69
SONET/SDH Outline
Basic Intro
Architecture
SONET Layers
SONET Frames
STS Multiplexing
SONET Networks
70
SONET/SDH
Digital transmission standards for fiber-optic cable
Independently developed in USA & Europe
• SONET(Synchronous Optical Network) by ANSI
• SDH(Synchronous Digital Hierarchy) by ITU-T
Synchronous network using synchronous TDM multiplexing
All clocks in the system are locked to a master clock
It contains the standards for fiber-optic equipments
Very flexible to carry other transmission systems (DS-0, DS-1, etc)
17-71
SONET/SDH Architecture
Architecture of a SONET system: signals, devices, and connections
Signals: SONET(SDH) defines a hierarchy of electrical signaling levels called STSs(Synchronous Transport Signals, (STMs)). Corresponding optical signals are called OCs(Optical Carriers)
17-72
SONET/SDH Architecture
SONET devices: STS multiplexer/demultiplexer, regenerator, add/drop multiplexer, terminals
17-73
SONET/SDH Architecture
Connections: SONET devices are connected using sections, lines, and paths
Section: optical link connecting two neighbor devices: mux to mux, mux to regenerator, or regenerator to regenerator
Lines: portion of network between two multiplexers
Paths: end-to-end portion of the network between two STS multiplexers
17-74
SONET Layers SONET defines four layers: path, line, section, and photonic(Physical)
Path layer is responsible for the movement of a signal from its optical source to its optical destination
Line layers is for the movement of a signal across a physical line
Section layer is for the movement of a signal across a physical section, handling framing, scrambling, and error control
Photonic layer corresponds to the physical layer of OSI model
17-75
SONET Frames Each synchronous transfer signal STS-n is composed of 8000 frames. Each frame is a two-dimensional matrix of bytes with
9 rows by 90 × n columns.
Each byte in a SONET frame can carry a digitized voice channel
17-76
SONET Frames In SONET, the data rate of an STS-n signal is n times the data rate of an STS-1 signal
In SONET, the duration of any frame is 125 μs
17-77
Client Layers of the Optical Layer Outline
SONET/SDH
Optical Transport Network(OTN)
Ethernet (Gigabit)
Generic Framing Procedure(GFC)
IP
Multi Protocol Label Switching(MPLS)
Resilience packet ring (RPR)
Storage Area Network(SAN)
Optical Transport Network (OTN) Outline
Basic Intro
Key Functions
OTN line rates
OTN Hierarchy
Frame Structure
OTN Features
Simpler than SONET/SDH
Scalable for higher rates
Cost effective
Optimized for carrier WDM networks
Transparent delivery of client signals.
Optical Transport Network (OTN)
OTN was designed to provide support for optical networking using wavelength-division multiplexing (WDM) unlike its predecessor SONET/SDH.
ITU-T Recommendation G.709 is commonly called Optical Transport Network
Optical Transport Network (OTN)
• OTN
• SONET/SDH
• Ethernet/FibreChannel
• Packets
Signals that OTN equipment processes are:
• Forward error correction (FEC) on OTN signals
• Management
• Protocol transparency
• Asynchronous timing
• Multiplexing and de-multiplexing of OTN signals
• Mapping and de-mapping of non-OTN signals into and out of OTN signals
key functions performed are:
OTN line rates compared to SONET/SDH line rates
OTN Line rates SONET/SDH Line rates
OTU 1: 2.666 Gb/s STS-48 2.488 Gb/s
OTU 2:
10.709 Gb/s STS-192 9.953 Gb/s
OUT 3:
43.018 Gb/s STS-786 39.813 Gb/s
Converged transport over OTN
OTN Hierarchy
OTN Frame structure
Frame consist of 4080 columns and 4 rows of bytes
Frame starts from left top corner to bottom right corner
Each row has 16 no of FEC block with size 255 bytes.
Overhead is in 15 & 16 column in frame
Client Layers of the Optical Layer Outline
SONET/SDH
Optical Transport Network(OTN)
Ethernet (Gigabit)
Generic Framing Procedure(GFC)
IP
Multi Protocol Label Switching(MPLS)
Resilience packet ring (RPR)
Storage Area Network(SAN)
Ethernet
MAC layer- CSMA/CD
Point-to-Point link
LAN- topology , repeater ,VLAN , VPN
Switches –Spanning Tree & Link Aggregation Protocol
Ethernet Physical Layer
Gigabit Ethernet 802.3z
(a) A two-station Ethernet. (b) A multi-station Ethernet.
Gigabit Ethernet(2)
Supports two different modes of operations
1> full duplex 2> half duplex
In full duplex mode switch is used. In this contention is not possible so CSMA/CD protocol is not used.
In half duplex mode hub is used. In this collision is possible so CSMA/CD protocol is used.
Two features
• 1. carrier extension
• 2. frame bursting
Gigabit Ethernet (3)
Gigabit Ethernet cabling.
Gigabit Ethernet (4) Gigabit support both copper and fiber cabling
Signaling at 1Gbps over fiber means that light source has to be turned on and off in under 1nsec
LED’s can not operate at this speed so lasers are used
Three fiber diameters are permitted : 10,50 and 62.5 microns
Two wavelengths are permitted : 0.85 and 1.3 microns
On fiber new encoding scheme 8B/10B is used ie each 8bits is encoded as 10 bits on fiber
1024 possible code words for each input is possible so two rules are available to make the decision
1> No codeword have more than 4 identical bits in a row
2> No codeword may have more than six 0s or six 1s
Ethernet Frame Format
PRE SOF DA SA Length/Type Payload FCS
PRE SOF DA SA VLAN Header Length/Type Payload FCS
a. Basic Ethernet Frame
b. VLAN Ethernet Frame
Ethernet Frame Format
Preamble (PRE)-Used to indicate start of frame for synchronization
Start of delimiter (SOF)- indicates start of rest of the frame
Destination Address (DA)
Source Address (SA)
Frame Check Sequence (FCS) – For error detection
Client Layers of the Optical Layer Outline
SONET/SDH
Optical Transport Network(OTN)
Ethernet (Gigabit)
Generic Framing Procedure(GFC)
IP
Multi Protocol Label Switching(MPLS)
Resilience packet ring (RPR)
Storage Area Network(SAN)
Resilience packet ring (RPR)
It is a packet switched ring N/W that transport IP data packet.
Its applications are MAN & WAN
It provide services like:
• Guaranteed bandwidth
• constant bit rate
• low delay service and
• best-effort service.
This topology is resilient(flexible) to failure.
Resilience packet ring- Ring N/W
Ring N/W is bidirectional formed by two counter rotating ring called ringlet 0 and 1
There are 2 types of frames: transit frame & ingress frame
Transit frame which have accessed a ringlet
Ingress frame are new frames waiting for adding into ringlet.
Ringlet 0
Ringlet 1
Resilience packet ring- QoS
RPR supports 3 classes of traffics
•Class A: low latency and jitter
•Class B: Predictable latency & jitter
•Class C: Best effort transport
Client Layers of the Optical Layer Outline
SONET/SDH
Optical Transport Network(OTN)
Ethernet (Gigabit)
Generic Framing Procedure(GFC)
IP
Multi Protocol Label Switching(MPLS)
Resilience packet ring (RPR)
Storage Area Network(SAN)
Storage-Area Networks (SANS)
SANs are networks used to interconnect computer systems with other computer systems and peripheral equipments such as disk drives, printers and tape drives.
A key part of SANs is Switch which provides reconfigurable connectivity between the various attached devices.
SANs are typically operate at bit ranges ranging from 200 Mb/s to 10 Gb/s.
Operate over fiber optic links.
Fiber channel protocol become the leading SAN.
Storage Area Network (SAN)
A Storage Area Network (SAN) is a specialized, dedicated high speed network joining servers and storage, including disks, disk arrays, tapes, etc.
Storage (data store) is separated from the processors (and separated processing).
High capacity, high availability, high scalability, ease of configuration, ease of reconfiguration.
Fiber Channel is the de facto SAN networking architecture, although other network standards could be used.
101
SAN Benefits
Storage consolidation Data sharing Non-disruptive
scalability for growth Improved backup and
recovery
Tape pooling LAN-free and server-free data movement
High performance High availability server clustering
Data integrity Disaster tolerance Ease of data
migration Cost-effectives (total cost of ownership)
102
SAN Architecture
Switch
Tape drive
Disk drive
Printer CPUs
SAN Topologies
Fibre Channel based networks support three types of topologies:
Point-to-point
Loop (arbitrated) – shared media
Switched
104
References
• https://en.wikipedia.org/wiki/Virtualization
• https://en.wikipedia.org/wiki/Network_virtualization
• http://bradhedlund.com/2011/10/12/network-virtualization-is-like-a-big-virtual-chassis/
• https://sreeninet.wordpress.com/2014/03/29/network-virtualization-overview-and-commercial-solutions/
• https://www.opennetworking.org/sdn-resources/sdn-definition
• www.mhhe.com/engcs/compsci/forouzan/powerpoint/Chapter18.ppt
• groups.geni.net/geni/raw-attachment/wiki/clusterdvlan/MPLS.ppt
• www.slideshare.net/Convergent_Technology/gmpls-8193634
• facweb.cs.depaul.edu/cwhite/TDC%20460/SAN.ppt
• https://www.cpe.ku.ac.th/~plw/dccn/presentation/ch17.pdf
• https://www.cs.berkeley.edu/~tlavian/slides/Grid/294%20presentation.ppt
Thank You !