lan (local area network) to wan (wide area network) access

1Dr. Martin LandAccess NetworkingProtocols and Networks — Hadassah College — Fall 2021

AccessNetworking

Connecting the Userto the World


Small Office / Home Office (SOHO)LAN (Local Area Network) to WAN (Wide Area Network)

Ethernet

WiFi

ADSL

WiFi Access PointEthernet Switch

IP RouterADSL Modem

Cable‐based transmission protocol defined at PHY layerG.992.5ADSL

802.11

802.3

Wireless LAN protocol defined at DATA LINK and PHY layersWiFi

Cable‐based LAN protocol defined at DATA LINK and PHY layersEthernet

Internet


Laptop Browser to Web Server — Simplified View

Access

IP

ADSL

WiFi Router

WiFi

IP

ADSL

Access

IP

ServerInternetLaptop

PHYPHY

Data LinkData LinkWiFi

IPIPIP

TCPTCP

HTTPHTTP


ADSL — Asymmetric Digital Subscriber LineHigh speed transmission on standard voice line

POTS — plain old telephone service24 Mbps downstream3.3 Mbps upstream

Ref: JDSU, ADSL Technology, JDS Uniphase Corporation, 2005


ADSL Access Network

Ref: Vodaphone, Wholesale Layer2 DSL (W‐DSL‐L2I), VTCW011 ‐ I 03/13


Typical Bezeq ATU‐R

ADSL33 Mbps

IP Routing

802.3Ethernet

802.11WiFi


Bezeq Fast Internet Access

usermanagement

and IP datagramforwarding

IP datagramforwarding

Bezeq ISP

Internet routing

ADSL modem onpoint-to-point

channel

Server

IPnetwork

telephonenetwork

Client

switchedATM

network


Fast Internet Protocols — Envisioned Campus CasePPP

Point to Point ProtocolLogon + connection management

PPPoEPPP over EthernetVirtual point‐to‐point connection over shared LANClient opens private session with ISP

Client

Ethernet802.3

PPPoEPPPIPTCPApp

Router

802.3

PPPoEPPP


Fast Internet Protocols — Envisioned Campus CaseATM

Asynchronous Transfer ModeData Link protocol for broadband

telephone servicesPermits real time QoS

MPOA + AAL5Adaptation protocols for ATM

ADSLPhysical bit transmission

Client

Ethernet802.3

PPPoEPPPIPTCPApp

802.3

ADSLATMAAL5MPOA

PPPoE

Router

802.3

PPPoEPPP

802.3

ADSLATMAAL5MPOA

PPPoE

Bezeq


Fast Internet Protocols — Envisioned Campus Case

Connection to ISPClient runs Network Control Protocol (NCP) over PPPCHAP (challenge handshake authentication protocol) —User Name + PasswordISP authorizes user and engages IP forwarding

Client

Ethernet802.3

PPPoEPPPIPTCPApp

802.3

ADSLATMAAL5MPOA

PPPoE

Router

802.3

PPPoEPPP

802.3802.3

PHY

PPPoE

ADSLATMAAL5MPOA

PPPoE

Bezeq

802.3

PHY

PPPoEPPP

ISP

Connection to ISP


Fast Internet Protocols — Envisioned Campus Case

IP forwardingISP forwards IP datagrams to server via Internet backbone

Client

Ethernet802.3

PPPoEPPPIPTCPApp

802.3

ADSLATMAAL5MPOA

PPPoE

Router

802.3

PPPoEPPP

802.3802.3

PHY

PPPoE

ADSLATMAAL5MPOA

PPPoE

Bezeq

802.3

PHY

PPPIP

PHY

PPPoEPPP

ISPPHYServer

PPPIPTCPApp

Connection to ISPIP Routing


Fast Internet Protocols — Typical SOHO Case

Router/modem initiates connection to ISPRuns NCP over PPP over PPPoE over EthernetRouter provides always‐on Internet access over WiFi + Ethernet

Client

WiFi802.11

IPTCPApp

802.3

ADSLATMAAL5MPOA

PPPoEPPP

Router

WiFi

802.3802.3

PHY

PPPoE

ADSLATMAAL5MPOA

PPPoE

Bezeq

802.3

PHY

PPPIP

PHY

PPPoEPPP

ISPPHYServer

PPPIPTCPApp

Connection to ISPIP Routing


Telephone Network Local loop (last mile)

Analog voice + dataVoice 64 kbps (DS0)

PDH / SDH digital hierarchyDS0 streams combined to hierarchy of data rates1.544 Mbps (T1) to 40 Gbps (STM-256)

ESS7Hierarchical tree of central office switches for DS0 streams

ATMGeneral packet switch mesh Switches 2.5 Gbps streams

(STM-16)

local loop

ESS ATM

Central Office

Router

local loop

ESS ATM

Central Office

Router

local loop

ESS ATM

Central Office

Router


Digital Voice on Telco Telephone Sample analog voice signal every 0.125 ms

0.125 ms per voice sample 8000 voice samples / second

Round-off sample to 8-bit dataData {0, 1, 2, ... , 255}Sample = {158.276, 158.879, 159.724, 159.821, 159.312, 158.791}Data = {158, 159, 160, 160, 159, 159}

DS-0 stream(8000 samples / second) (8 bits / sample) = 64 kbps64 kbps digitized voice (no compression)

158 159160 160 159 159

157

158

159

160

161

t


Data Concentration Multiplexing

Combine multiple nodes onto one link

32 inputsat 64 kbps

1 output at2.048 Mbps

Multiplexor

32 outputsat 64 kbps

1 input at2.048 Mbps

Demultiplexor

39.81312 Gbps256 x E4STM‐2569.95328 Gbps64 x E4STM‐64

SDHPDH

2.48832 Gbps622.08 Mbps155.52 Mbps51.84 Mbps

16 x E44 x E4E4

21 x E1

STM‐16STM‐4STM‐1STM‐0

139.264 Mbps4 x E3E434.368 Mbps4 x E2E38.448 Mbps4 x E1E22.048 Mbps32 x DS0E1


Cellular NetworkWireless to base station — uses Telco network for WAN service

Base System (BS)

Telco VoiceNetwork

CellController

ClusterController

Mobile SwitchingCenter (MSC)

Public Land Mobile Network

Mobile Station(MS)

HLRVLR

CellCluster

GPRS

Internet

SGSN

GGSN

Voice

Data


3G Cellular Network


Enormous investment in existing equipmentGlobal network of hardware nodes + transmission lines

Developed to provide many servicesInternet (IP-based unreliable connectionless) just one service

Most developed before Internet Telegraph — 1794Telephone — 1876Teletype modem — 1943Digital telephone — 1962Internet opened to public — 1992

Hardware updates Replacement of manufactured hardwareSlower than software updatesMore expensive than software updates

Network InfrastructureEconomic perspective


Enterprise NetworksEnterprise

The word (ref: http://www.etymonline.com)Past participle of entreprendre — "undertake, take in hand" From Old French — entre "between" + prendre "to take"

The pose

Enterprise networkLarger + more complex + more expensive + more awesome than SOHOIntegrated LAN + WAN technologies

Traditionally implemented in specifically‐designed hardware systemsIncreasingly implemented as Software Defined Networks (SDN)

SecurityHigh overall traffic volume


Traditional Network InfrastructureCisco Smart Business Architecture (SBA) Ref: WAN Design Overview, Cisco 2013


Technologies in the Cisco SBA Conventional Layer 3 routing

Permits universal access to any host / nodeNext‐hop IP datagram forwarding

Conventional Layer 2 switching —N x N non‐blocking switchingPermits access to nodes on same physical networkEthernet MAC physical port‐to‐port switchingESS7 64 kbps voice telephone switchATM cell switching for switched and permanent virtual circuitsFrame Relay switching for permanent virtual circuits

PHY

Data Link

IP

PHY

Router

PHY

Data Link

IP

Next Hop by IP

PHY

Data Link

Next Hop by MAC or VC

NodeSwitchNode

PHYPHY

Data LinkData LinkData Link

IPIP

TCPTCP

HTTPHTTP


Technologies in the Cisco SBAVirtual LAN (vLAN)

LAN switch configured to partition nodes into subnetsNo router needed for subnet partitions

Virtual Private Network (VPN)Private network implemented on public infrastructure

Router Network

Subnet Subnet

Internet

Private Network Private Network

Access Restricted by IP

Programmable Switch


Technologies in the Cisco SBAMultiprotocol Label Switching (MPLS)

Label header added to IP datagramLabel identifies end-to-end routeImplements end-to-end virtual circuit

MPLS enabled router Next hop by MPLS labelFaster than next hop IP routing

Saves time of layer 3 processingDatagram read / write, routing, TTL

Switch / Router InteractionPermits vLAN and VPN definitionOptimizes multimedia streaming

Application TCP IP DL PHY

DL PHY

Application TCP IP DL PHY

DL PHY

DL PHY

DL PHY


Technologies in the Cisco SBANexus 7000 Switch

100 Gbps Ethernet switchCopper or fiber access portsQoS control

Cut-through architecture (forward data without buffering)Low latency + jitter

Extensible through fabric extenders (FEX)Scalable to 15.76 Tbps (15,760 Gbps)

Supports virtual networking through MPLS

Nexus 2000Fabric extender (FEX)Add remote ports to Nexus 7000

Ref: http://www.cisco.com


Technologies in the Cisco SBACisco XR 12000 Router

For large enterprises and service providers1280 Gbps capacityInternet protocols

IPv4/v6, MPLSBGPv4/v6, IS-IS, OSPFv2.0, RIPv2, IGMP, DVMRP, PIM DX/SX

Infrastructure protocolsSONET/SDH, Ethernet, ATM, copper (DS-3/E3)

Cisco 7600 RouterWAN router240 Gbps capacityInfrastructure — Telco leased lines DS0 to OC-192

Cisco 3900 RouterFor branch office4 Gigabit Ethernet ports


Facts of Life for Telephone Business 2000 — 2008Enterprise

Business revolves around data center Access + storage + processing + service

Employees still talkMobility = standardVideo calls growing — voice calls still cost money

Network infrastructure providers (Telcos)Most installed infrastructure designed for voice callsProfit in leased lines not voice calls

Internet + private WAN + mobile backhaulStrategy

Scrap PSTNCash-in central office real estateBuild data-oriented mesh networkSupport voice as media streaming

local loop

ESS ATM

Central Office

Router

local loop

ESS ATM

Central Office

Router

Switching Hierarchy


Next Generation Networks (NGN)ITU initiative for long-term network planning

Standardizes current view of technology convergenceITU-T Recommendation Y.2001 (12/2004)

All-IP networkEvery service over IPIP over every infrastructure

Universal gateway pointDissolve traditional service

boundariesUniversal mobilityEvery service to every user

QoS controlIPv6MPLSSIP

Every Service

Every Infrastructure

IP

Transport

Network

Physical

Data Link

Session

Presentation

Application

OSI Layer


What is Cloud Computing?Outsourcing service model

Replace user hardware/software with "computing as service"Service Level Agreement (SLA)

Defines service provided to userGuarantees performance and quality of serviceProvider handles operations+administration+maintenance (OAM)

Business advantagesEconomies of scale to large provider lower cost to userUser cuts labor/capital costs from balance sheet happy investors

Customers Pizza Online

X86 Server

Delivery

Customers Pizza Online Cloud Inc.

Delivery

Virtual X86

Service


What is Cloud Computing?Cloud service organized from conventional resources

User chooses service level agreement (SLA) from menuProvider offers menu

Mix of hardware + software + network typesSLA implemented with dedicated or virtual system

Dedicated systemConstructed to perform only one specific taskExample — WiFi access point

Virtual systemImplemented in software on a generic systemExample — Java code running on Java VM over Linux

Unique technological issuesService reliability — provider financially committed to SLAProvider-side — seeks minimum configuration cost for SLAUser-side — seeks minimum contract cost for requirements


Service Hierarchy in Cloud ComputingInfrastructure as a service (IaaS)

User sees virtual hardware environment Real hardware or hypervisor / system virtual machine

User installs OS installs software runs jobs

Platform as a service (PaaS)User sees virtual OS environment

OS on single hardware platform or virtual OSUser installs software runs jobs

Software as a service (SaaS)User sees virtual application software environment

Applications running on private OS or "sandboxed" on shared OSSandbox — private execution environment per application instance

User runs jobsStorage as a service (STaaS)

User sees virtual mounted storage device


Considerations in Cloud ComputingCost

Provider issuesEconomies of scale lower cost per compute job

User issuesCapital + OAM costs operating costsLower start-up costs operating debt

Reliability Provider issues

Redundant infrastructure continuity + disaster recoveryCentralized management of OAM, security, performanceVirtualization serve multiple users on physical serverMultitenancy provide multiple sandboxed application instances on OS

User sees guaranteed serviceAgility

User / provider reconfigure service / infrastructure as needed Growth, load balancing, time-zone serving


Cloud OwnershipPublic cloud

Service provider as public utility — sells / rents computing serviceInitial providers leverage large existing infrastructureAmazon, Microsoft, Google, IBM

Menu of services at fixed prices

Private cloudCloud infrastructure for private organizationManaged internally or outsourcedIsolates service developers from implementation issues

Standard development platformRequirements for economic justification

Large organization Technology-based servicesFrequent new serviceExample — internet content provider


What's Different in Cloud NetworkingEnd user

Not muchAccesses service "somewhere" on network

Business service providerDefine business serviceOutsource implementationOAM limited to SLA-level virtual environment

Cloud service providerManage vast real environment mapped to virtual environmentsOAM requires effective picture of real system from SLA POV


Networking FunctionsForwarding function

Data transferImplement network protocolsHigh performance dedicated hardware

Control functionManagement of forwarding function

Configuration of network topology and policiesSupervision, measurement, maintenance

Traditional controlImplemented in dedicated hardware Switches, cable connections, programming at console interface

Software Defined Networking (SDN) control Implemented in system softwareGeneric control interface in hardwareSystem programmer configures modes, connections, policies


Software Defined Networking (SDN)SDN Application

Programs communicate network requirements to SDN Controller Receive abstracted view of network for planning

SDN ControllerTranslates requirements from SDN application to SDN Datapaths Provides SDN applications with view of network

SDN DatapathLogical network device controls data forwarding hardware

Single forwarding device Logical device defined from internal network of forwarding devices

FabricHardware associated into SDN


Cisco Software‐Defined Access DesignUnderlay network

Physical dedicated hardwareOverlay network

Virtual network implemented in SDNManagement

Identity Services Engine (ISE)Account database

DNA CenterHardware database

Border nodeConnects fabric to WAN

Edge nodeConnects fabric to user

References: https://www.cisco.com/c/dam/en/us/td/docs/solutions/CVD/Campus/CVD‐Software‐Defined‐Access‐Design‐Sol1dot2‐2018DEC.pdfhttps://www.cisco.com/c/dam/en/us/solutions/collateral/enterprise‐networks/enterprise‐network‐security/data‐center‐design‐playbook.pdf


Layer 2 OverlayLayer 2 (Data Link) Logical network

Edge switchesEthernet, etcConnect users

Intermediate switchBorder switches

Physical networkPhysical switchesCables


Layer 3 OverlayLogical IP + switched network

Edge and border switchesIntermediate IP router

Physical networkSame as Layer 2Physical switchesCablesIP routing implemented

in software


Centralize Decentralize Centralize ?1950s — 60s

Centralized mainframe computer + multiple OS instances over hypervisorTimesharing OS serves multiple usersUser sees OS environment via dumb terminal (thin client)

1970s User applications offloaded to minicomputers + timesharing servicesUser sees timeshared OS environment via dumb terminal

1980sUser applications offloaded to personal workstations (PC)User sees single-user OS environment running locally

1990sNetwork single user workstations User sees single-user OS environment running locally

2000sCentralized control of local OS environment by IT departments

2010sCloud + netbook / tablet / smart phone — dumb terminal with high-res GUI


What Network Access Providers Do

https://www.rad.com/system/files/Media/rad‐catalog‐2019.pdf


VirtualizationHighly configurable network hardwareSoftware defined network (SDN) functions

NID—Network Interface DeviceNTU—Network Termination Unit

for Carrier Ethernet

Distributed Network Functions Virtualization (D‐NFV)


Carrier EthernetEthernet

802.3 CSMA/CD shared medium local area (~ 100 m) networkData rates — 10 Mbps to 100 Gbps on copper or optical fiber

Carrier EthernetBridge Ethernet LAN segments over WANOperates as single Ethernet broadcast domain

E-Line — point-to-point connectionE-LAN — general meshE-Tree — hierarchical tree


Cyber Security

EthernetETHTerminal Protocol (?)TP

Remote Terminal UnitRTU

Intelligent Electronic DevicesIED

MAC layer security standard (802.1AE)MACsec

Supervisory Control and Data AcquisitionRemote Monitoring and Control

SCADA

Data Communications ChannelPort Based Network Access Control (802.1X)

DCC


vCPE (virtual customer premises equipment)

VNF — Virtualized Network FunctionGPON —Gigabit Passive Optical NetworkPDH — Plesiochronous Digital Hierarchy (standard telco multiplex hierarchy)GbE—Gigabit EthernetL2/L3 — layer 2 (data link) switching + layer 3 (IP) routing


Carrier Ethernet

ETXCarrier Ethernet demarcation and aggregation

MinID login system


TDM Over Packet Mode Networks

PSNPacket Switched Network

PBXPrivate Branch Exchange — telephone switchboard


Cellular Backhaul

Cell site2G BTS or 3G/4G Node B (NB/eNB) connects mobile device to cellular network

BackhaulCarry digital voice from mobile cell site to telephone central office

lan (local area network) to wan (wide area network) access

Documents