Introduction to OSS - BGUteln121/wiki.files/Intro to Networks.pdf · Presentation Presentation Physical Physical ... Plesiochronous Digital Hierarchy ... Synchronous Digital Hierarchy

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Introduction to Networks

Yossi Nygate, PhD

VP Strategy and Architecture

November, 2011



What is a Network?

Network

Network Types

Telephone/Voice Networks

Data Communications

Networks

Video Networks

Mobile Networks

Networks are made up of

Infrastructure

Communications protocols

User applications

Network Terminology

Network Carrier

Public Network Service Provider

MSO – Multi Service Operator

(Cable)

Virtual Network Provider

ISP - Internet Service Provider



Network Types

Network Size Technology Licensing Notes

WAN Cover a large

area

E1/T1,

SDH/SONET,

Frame Relay,

ATM,……

Needs a service

license

Many diverse

technologies

LAN Within a campus Ethernet No license within

campus

One technology. Many

options

MAN Covers a city Metro Ethernet Needs a regional

service license

Newer players

Access Last “mile” Copper twisted

pair

Cable

Wireless

Usually

infrastructure

license

Access to Networking

Services - Voice,

Data, Video

Fibre Optics emerging



Network Terminology

> Connection Oriented (Circuit Switching)

> Dedicated path used for duration of service

> Connectionless (Packet/Cell switching)

> Data is divided into packets – route each packet

takes can vary

> Packet sizes can change, cell sizes are constant

> Quality of Service (QoS)

> Throughput, delay, jitter

> Rings and Rerouting

> Technologies to support high reliability

> Rings – additional hardware

> Rerouting – additional intelligence

> Network Element (switch/router)

> (Semi)Intelligent device that selects a path for

sending a unit of data to its next destination



Network Transmission Media

Twisted pair wires

Telephone Twisted Pair (TTP)

Unshielded Twisted Pair (UTP)

Shielded Twisted Pair (STP)

Coaxial cable

Thin/Thick/TV

Broadband

Fiber-optic cable

Multi Mode

Single Mode

Radio/wireless



Modern Data Communications Concepts are based

on the OSI (Open Systems Interconnection) Model

The Model terminology is used by Telecoms Service

Providers and Professionals

Provide Data Communications Structure

Concepts:

Networking Layers defined

Within each Layer define

What needs to be done

How it is done

The OSI Seven-Layer Model



Transport

Application

Session

Network

Data Link

Physical

Data Link Data Link

Protocol

Interface

Transport

Application

Session

Network

Data Link

Physical 1

2

3

4

5

6

7

End System End System

Relay System Relay System

Presentation Presentation

Physical Physical

Network Network

The OSI Model



Function of Layered Architecture

Web surfing, email, file transfer, etc...

Data formatting and encryption

Setup & maintain application sessions

End-to-end reliable data delivery

Route packets through an internetwork

Framing, Error Checking, Flow Control

Cables, Connectors, Voltages, Coding

Transport

Application

Session

Network

Data Link

Physical

Presentation

1

2

3

4

5

6

7



64 Kbps

1,544 Kbps 6,312 Kbps 44,736 Kbps 274,176 Kbps

2,048 Kbps 8,448 Kbps 34,368 Kbps 139,264 Kbps 564,992 Kbps

DS0

T1/DS1 T2/DS2 T3/DS3

E1 E2 E3 E4

x 24

x 30

x 4 x 7 x 6

x 4 x 4 x 4 x 4

FIRST

ORDER

SECOND

ORDER

THIRD

ORDER

FOURTH

ORDER

T4/DS4

PDH Transmission Hierarchy

PDH – Plesiochronous Digital Hierarchy

Almost synchronous

Each 1.5/2Mbps pipe (primary system) has own timing system



TDM – Time Division Multiplexing

> Allocation of fixed length time slots to each channel

> Time slots are assigned and built into fixed length frames

> Each frame begins with a synchronization marking point

> Carrier Implementation

> ANSI - T1 System – 24 time slots + Synch – 1.544Mbps

> ITU - E1 System – 30/31 time slots + synchronization – 2.048Mpbs

SYN CH1 CH2 CH3 CH4 SYN CH1

SYN CH1 CH2 CH3 CH4 SYN CH1

One Frame

TDM

Multiplexer

TDM

Multiplexer

CH1

CH2

CH3

CH4

CH1

CH2

CH3

CH4





SONET/SDH Objectives

Design a new transmission system

All digital transmission designed to utilize optical fiber networks

Completely synchronous network at different rates

Use Hierarchical/Recursive modeling scheme

Simplified Multiplexing/Demultiplexing technique

Consolidates and segregates traffic from different facilities

Automatic Network Protection Mechanisms

Integrated OAM & P (Operation, Administration, Maintenance and

Provisioning)

Co-ordination between US and European Transmission facilities

US –ANSI - SONET – Synchronous Optical Network

Europe – ITU-T– SDH – Synchronous Digital Hierarchy



The Carrier Backbone

The older first generation network

remains as an access option at the

lower speeds. A strucured

hierarchy of point to point PDH

transmission circuits (E1/T1

circuits)

The newer core network hierarchy

termed SDH or SONET at the

higher speeds.

The two technologies formed the

basis of the carrier circuits that

carry the voice and data traffic

To simplify the carrier backbone

management and raise speed a newer

fibre based ring technology was

introduced – termed SONET (US) or

SDH (Europe)

SDH Hierarchy

PDH Hierarchy



SDH Add Drop Multiplexers

E/T1

SW

1

SW

2

E/T1

SW 3

FIBER OPTIC

SDH/SoNET

RING

E/T1

ADM – Add/Drop Multiplexor -the

network can pick up and drop

channels at intermediate points

Fully synchronized network that

can carry the point to point data

channels

Alternate Channels can be

provisioned to enable fast

recovery using ring based

protection mechanisms (50 msec

recovery)



SDH Bit Rates

RATE INFORMATION STRUCTURE

bps SDH SONET

51.84M – STS-1 (OC-1)

155.52M STM-1 STS-3 (OC-3)

622.08M STM-4 STS-12 (OC-12)

2.48G STM-16 STS-48 (OC-48)

9.6G STM-64 STS-192 (OC-192)





DWDM - Increasing Capacity of Fiber Networks

Single Fiber (One

Wavelength)

Channel 1

Channel n

Single Fiber (Multiple

Wavelengths)

l1

l2

ln

• More Fiber

• TDM - Time Division Multiplexing

• Single wavelength per fiber

• Multiple channels per fiber

• 4 OC-3 channels in OC-12



• WDM - Wave Division Multiplexing

• Multiple wavelengths per fiber

• 4, 16, 32, .. channels per system

• Multiple channels per fiber

• Multiple Protocol types



WDM – Wave Division Multiplexing

To increase the capacity of optical fibers, WDM allows the simultaneous

transmission of several signals at different wavelengths

Usually divides into 2,4,8,16… by powers of 2

The most effective wavelengths are around 1500 nanometers

The amplifiers, can amplify the optical signals in the optical domain

Wave Division Multiplexing has developed into several complementary

technologies

DWDM – Dense Wave Division Multiplexing

CDWM – Coarse Wave Division Multiplexing



Frame Relay

Router

Router Router

Router

Customer Network Customer Network

Customer Network

Frame Relay offers high speed

packet data communications.

The connection

Access Line (64Kb – 45Mb)

PVCs - Permanent Virtual Circuits

that replace a point to point line

CIR - Committed Information Rate

Each PVC is tariff rated on

throughput guarantees

Error Handling

End-to-End - User responsibility

Customer Connection

Customer Router – routes the

packets over the appropriate PVC

CIR 64K

CIR 19.2K

CIR 0

CIR 0

Customer Network



ATM – Asynchronous Transfer Mode

ATM Network Objective

Streamlined Network Technology for

carrying all types of data

Voice

Data

Video

Usage

Carrier Backbones

National ISPs

Backbone ISPs

High Capacity Enterprise Customers

Technology

High Speed fixed Length Cell Switching

Site B

Site A

Site C

Site D

Site E Site F

Site G

Site H



ATM - Traffic Profiles

> CBR – Constant Bit Rate

> Users get a fixed bandwidth connection.

> VBR – Variable Bit Rate

> Users get a minimum bandwidth guarantee

known as the Sustainable Cell Rate (SCR) and

are can burst above that level within limits

> ABR – Available Bit Rate

> Users equipment has to adjust transmission

rates between maximum and minimum levels in

response to feedback from the ATM network.

> UBR – Unspecified Bit Rate

> Offers a “best effort” service intended for non-

critical applications. Cells are tagged for possible

discard if there’s congestion in the network.

There are no guarantees of minimum or

maximum delays.

Variable Bit Rate

Available Bit Rate

Constant Bit Rate





Routing Technology

In the real world an internet

connects different networks,

particularly LANs and WANs.

Routers understand the specific

protocols of the networks they

connect

The term Gateway is also used

Routing Technology

Defines a common addressing

scheme

Find the best path to deliver packets

between workstations

Shortest

Fastest

Least congested

Most secure

Router

Ne

t 41

Router

RouterRouter

Net 61

Net 21Net33

Mainframe

Terminal

Terminal

Net 42

Net31

(Host 42,1)

(Host 21,1)

WAN Carrier

Networks



Routing Protocol Terminology

> Statically set up by Network Administration

> Dynamic - Learned and constructed by routing protocols

> Half Dynamic - Flow based routing for carriers

> Routing Protocol (Algorithm) - used to send topology information and

updates across the network

WAN



Dynamic Routing Protocols

BGP (Border Gateway Protocol) : Inter-domain protocol

Exchanges routing information between the routers in a

network of AS

Autonomous System

(AS) AAutonomous System

(AS) B

IGP (Interior Gateway Protocol) : Exchanges routing information between routers within an AS

Commonly used IGPs: • RIP - Routing Information Protocol (legacy)

• OSPF - Open Shortest Path First Protocol

An Autonomous system (AS) is a

collection of IP networks and routers

under the control of one entity that

presents a common routing policy.



The World of Routers

Routers

Core (P - router)

Campus/Carrier Class

Provider Edge (PE-Router)

Customer Edge (CE-Router)

Main & Branch Office

Home Router

Broadband Access

Routed Protocols

IP Others - IPX, DECnet

Interfaces LAN – Ethernet

WAN – LL, FR, ATM, Ethernet..

Vendor Specific

Hardware/Software

Operating System, User Interface

Routing Algorithms

Standard, Proprietary

Filtering and Security

Access Lists

Firewall

Quality of Service Features

Edge

Router

Customer

Router

Core

Router



What is Internetworking?

> Users are connected to specific network technologies (LAN, WAN)

> An internetwork (or internet) is a network that connects and provides connectivity between different network technologies

> Routers are the boxes which connect the networks

MAN

Frame

Relay

L

AN

Host Sites

Mobile

Leased Line

Access Router

Router

Router

Router

Router

Router Router

ATM

Broadband





IP Architecture

> Transmitting Station

> Takes data from transport layer, and inserts IP

datagrams into the network

> Routers

> Calculate Output Route

> Fragment, if necessary

> Forward packet on to the next node

> Receiving Station

> Reassembles the fragments

> Passes the packet to Transport layer

> IP Provides

> A packet delivery mechanism

> An Internet addressing scheme

> IP is unreliable - datagrams can be:

> Lost

> Duplicated

> Delivered in the wrong order

> Scrambled upon arrival

Source Destination

Routers



The TCP/IP Protocol Stack

FTP

TCP

IP - CONNECTIONLESS

DATAGRAM DELIVERY

Networks lll

WAN

LAN

WAN

Internet Layer

Transport Layer

Applications

UDP

HTTP

SNMP

Telnet



Transport Architecture

TCP – Transmission Control Protocol

An End-to-end, connection-oriented,

transport protocol

A Reliable (byte) stream transfer

Full-duplex connections

Flow control

Delivery to the appropriate

application

UDP – User Datagram Protocol

Best attempt delivery to the

appropriate application

Typical TCP applications

File Transfer

Electronic Mail

Web Browsing

Typical UDP applications

Voice

Networking management

application

TCP

IP

Physical

TCP

IP

Physical

application application application





Fiber Access

FTTH - Fiber Optic path from the CO to the user premises (Home)

More expensive installation

30 – 100 Mbps

30% less expensive operating costs than FTTN

CO

CO

FTTN - Fibre Optic path to the Neighborhood

Within 3000 feet of home

Inexpensive/quicker installation

25 -50 Mbps



Emerging Access Technologies - FTTx

> FTTx Flavours

> Fiber To The Home (FTTH)

> Fiber To The Premise (FTTP)

> Fiber To The Curb (FTTC)

> FTTx Network Technologies

> B-PON (ATM based)

> G-PON (GE based)

> Converged Copper/Fiber Access

> Support Triple Play Services in the Access to the Core

Network (e.g. Voice, Data, Video)

> “Last mile” either fiber or xDSL technology



FTTx Versus Other Technologies

Upload DVD in 10 mins

“Connected Home”

Next-gen TV Super Hi-Vision

Family: 2x HDTV + 2x HSI + up/download

2 channels HDTV + iPlayer

HD PC video conference

1 Channel 3D TV + 1xHD + 3x HSI

Family HD videocall

1GB backup in 10 mins

1 x HD YouTube

Internet

FTTH: FUTURE-PROOF INFRASTRUCTURE FOR CONNECTED HOME SERVICES

ACCESS NETWORK TECHNOLOGY

UPSTREAM CAPACITY (MBIT/S) DOWNSTREAM CAPACITY (MBIT/S)

ADSL/2+/M

CATV/HFC-DOCSIS

FTTH/1G

FTTH/100M

1000 100 50 20 10 10 20 50 100 1000

FTTH provides

the highest

bandwidth

VDSL2



Layer 2 - Ethernet versus ATM

ATM Ethernet

Networks WAN LAN

Designed for Voice, Data, Video Data

Packets Fixed Length

Short

Variable Length

Communications Connection Oriented Connectionless

QoS features Excellent Classes of Service

Infrastructure Fibre, Microwave Copper, Fibre, Wireless

Cost High Low



FTTx

High

Bandwidth

Services-

VOD, VoIP,

IPTV,

Data

Aggregation

Switches

Fiber on PON

Active Ethernet

Service Provider

Core Network

Application & Content

VOD Libraries

IPTV

MPLS Core Fulfillment

Device

Management

SPs Customer

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The X in FTTx

> Fibre To the (x)

> Node, street cabinet km’s away

> Cabinet, local street cabinet

> Building, use copper within building

> Home, fibre up to individual dwelling units

> Why

> Gradually improve bandwidth (backhaul and

access)

> Revenues help pay for more rollout

> Gradually test take up rates

> I.e. cost optimize rollout

> Dual copper/fiber how to

> Fibre to a mini DSLAM, Ethernet switch or CMTS

> Copper to customer, just like normal

DSL/cable/Ethernet service

> Powered, temperature controlled cabinets

(street/building)

Source:

http://en.wikipedia.org/wiki/Fiber_to_the_x

http://fibresystems.org/cws/article/tech/38232



Ethernet Evolution

1976 Metcalfe &

Boggs 1980 DEC,

Intel, Xerox "blue book"

1985 IEEE 802.3 Ethernet

10 Mbps

2.94Mbps 10Mbps

1981

1995 100Mbps IEEE Fast Ethernet

First Products

1997 1 Gigabit Ethernet over

Fiber

1999 1 Gigabit Ethernet over

Copper

1994 1997

100Mbps 10Gbps 1Gbps

2001

2001 10 Gigabit

Ethernet LAN

2001 10 Gigabit

Ethernet WAN

Management, Higher

bandwidth, wireless

Adoption of Ethernet datagram by other technologies

1970s 1980s 1990s 2000s

Expansion from LAN to MAN

Ethernet has evolved from a simple local shared data networking technology

to the dominant Layer 2 technology for transporting all types of information



> Speed

> 10Mbs, 100Mbps, 1Gbps or 10Gbps

> Reachability

> Switched Ethernet and fibre extend to 10s of km’s

> Cost

> 1 Gig Ethernet switch port costs about 1/100th of the equivalent

capacity of router port

> Service guarantees

> Capacity, QoS, Reliability

> Simplicity

> Plug and go

Rise of Carrier Ethernet in the Metro and WAN



Carrier Ethernet

The Concept

Ethernet was built for LAN and now

extended to offer transparent

Ethernet service across a MAN or

WAN cloud

Access Line

Standard - 10,100,1000Mb

Evolved to 10 and 100 GB

Use VLANs to separate and

prioritize traffic

Can stack VLANs (Q-in-Q)

Provisioning

All Ethernet Switches

Scalable Bandwidth

Ethernet Aggregation

Ethernet has also proved useful as

an technology to aggregate access

traffic

Switch



Ethernet

Metro

Cloud

Switch

Switch Switch



Wireless

Backhaul

Voice gateway

Voice/Video Telephony

HD TV TVoD, VoD

Gaming, Business Backup, ERP

E-Line and

E-LAN service

FTTx and DSLAM , Cable Modem

Broadband

mobile data/video

Video Source

Video Source

Carrier

Ethernet Access

Global/National

Carrier Ethernet

Metro Carrier

Ethernet

Business

Broadband

Small/Medium

Business

Carrier Ethernet Scope and Expansion

Residential

Triple-Play

Documents

Introduction to OSS - BGUteln121/wiki.files/Intro to Networks.pdf · Presentation Presentation Physical Physical ... Plesiochronous Digital Hierarchy ... Synchronous Digital Hierarchy