computer networks unit -6 advance network technologiescomputer networks unit -6 advance network...

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)

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)

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

ATM: Asynchronous Transfer Mode

Overview

Protocol Architecture

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

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

VPI and VCI: Hierarchical Switching

Identifiers and Cells

ATM Layer and Headers

ATM: Asynchronous Transfer Mode Overview

Networks: ATM 26

agemen

Management plane

Control plane User plane

Physical layer

ATM layer

ATM adaptation layer

Higher layers Higher layers

Layer man

ATM Layers

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

• Bit timing, line coding

• Physical medium

Physical Media Dependent

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

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

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

AAL3/4

Chapter Outline

Virtualization

GMPLS Outline

Part I: MPLS

Part II: GMPLS

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)

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

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

Signal Converter Light

Source

Source-to-Fiber

Interface

Fiber-to-light

Interface

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.

About Light Rays (Angle of Reflection)

Glass material

with slightly

lower density

ain Glass material

with slightly

higher density

refraction Total

refraction reflection

Plane of Interface

Types Of Optical Fiber

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

Optical Fiber network uses Wavelength-Division Multiplexing

WDM sends information through a single optical Fiber using lights of different wavelengths simultaneously.

Optical sources

Optical detectors

Optical

amplifier

Multiplexer Demultiplexer

Application

Telecommunications

Local Area Networks

Cable TV

Optical Fiber Sensors

Chapter Outline

Virtualization

Client Layers of the Optical Layer Outline

SONET/SDH

Optical Transport Network(OTN)

Ethernet (Gigabit)

Generic Framing Procedure(GFC)

Multi Protocol Label Switching(MPLS)

Resilience packet ring (RPR)

Storage Area Network(SAN)

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

• 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

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)

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)

SONET devices: STS multiplexer/demultiplexer, regenerator, add/drop multiplexer, terminals

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

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

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

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

SONET/SDH

Ethernet (Gigabit)

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

SONET/SDH

Ethernet (Gigabit)

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

SONET/SDH

Ethernet (Gigabit)

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

SONET/SDH

Ethernet (Gigabit)

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.

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)

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

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 !

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