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dr Nenad Krajnović

Elektrotehnički fakultet u Beogradu

E-mail: krajko@etf.bg.ac.rs

The ARPANET – početak...

� Growth of the ARPANET (a) December 1969. (b) July 1970.

� (c) March 1971. (d) April 1972. (e) September 1972. 2

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Interconnection of Backbone

ISP Networks

POPPOP

POPPOP

POPPOP

POP

POPPOP

POPPOP

POPPOP

POPPOP

POPPOP

NAPIXP

Path Choice

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POPPOP

POPPOP

POPPOP

POP

POPPOP

POPPOP

POPPOP

POPPOP

POPPOP

NAPIXP

0.5$/MB

0.15 + 0 + 0.10 = 0.25 $/MB

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Commercial Impact on the Global

Network

� There is no such thing as global backbone any more!

� There is no such thing as Internet core any more!

� Backbone of the global network consists of backbone ISP networks, mutually interconnected at the Internet Exchanges (ex NAPs).

� The core of the networks consists of routers, switches and other devices, located in the ISP backbones, preventing the global network from splitting into parts.

� Routing policies between major backbone ISPs determine the ways of traffic flow on the Internet today.

� Routing policies don’t assure optimal routing - the main criterion for the routing policy design is - the cost of the links!

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Network Access Points and

Internet Exchanges (NAPs & IXs)

1. IXPs in the USA:• SIX – Seattle, Salt Lake City, Vancouver

• NYIIX – New York International Int. Exch.

• DET-IX – Detroit Internet Exchange

• DE-CIX, LINX, Equinix, W-IX,...

2. Major European NAPs:• DE-CIX - Frankfurt am Main

• AMS-IX – Amsterdam

• LINX – London

• Netnod – Stockholm, Malmo, Sundsvall...

• SOX – Serbian Open Exchange

https://www.eurohttps://www.euro--ix.net/ixps/listix.net/ixps/list--ixps/ixps/

Traffic on DE-CIX

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Arhitektura DE-CIX-a

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Traffic on LINX - 01.03.2016.

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Arhitektura LINX-a (2016.) – I deo

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Arhitektura LINX-a (2016.) – II deo

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Traffic on AMS-IX – 01.03.2016.

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Arhitektura AMS-IX-a (2016.)

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Traffic on Netnod – 01.03.2016.

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Traffic on Seattle IX – 29.02.2016.

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Architecture of Seattle IX

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Traffic on NYIIX – 29.02.2016.

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Traffic on SOX – 01.03.2016.

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Access Networks - Overview

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Backbone Technologies

LAN technologies (LAN technologies (PoPsPoPs, NAPs):, NAPs):�� Fast and Gigabit Ethernet (0.1Fast and Gigabit Ethernet (0.1--1Gbps)1Gbps) – almost ultimate PoP LAN

technologies today.�� 10Gbps Ethernet10Gbps Ethernet – developed, implemented on biggest sites.�� 100Gbps Ethernet100Gbps Ethernet– new standard for high demand sites.

WAN technologies (backbone lines):WAN technologies (backbone lines):�� LongLong--haul Gigabithaul Gigabit,, 10G Ethernet10G Ethernet and 100G Ethernetand 100G Ethernet

� Mostly metropolitain area.� On xWDM optical transport networks Gigabit and 10G Ethernet

can be offered in WAN networks.

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Backbone Interconnectivity

� In order to exchange traffic, ISP’s must be connected to each other.

� Every ISP should consider:� Buying transit connectivity from one or more larger-sized ISP’s (a must for

business!)

� Interconnecting (for free!) its network with other local ISP’s of the same size:� Not a must for business and not always achievable (politics ...).

� National ISP’s should be interconnected to other national ISP’s in the same country.

� Same goes for regional ISP’s – they should interconnect with other partners in the region.

� Exceptional case are International backbone ISP’s:� Example: UUnet, TeliaSonera, Level3, Combridge, Sprint ...

� They don’t buy transit service from anyone (they are transittransit--freefree).

� They interconnect their network (for free!) with other backbone ISP’s.

� Interconnection between backbones is usually called peeringpeering.

�� PeeringPeering can be:�� PublicPublic – implementing by bringing backbone routers to the public IX/NAP’s.

�� PrivatePrivate – usually a leased line or local cable between two backbones.

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Internet Routing

� Protocol responsible for routing is IP (IP (Internet ProtocolInternet Protocol)).� Connectionless!� Based on hophop--byby--hophop paradigm, each router being a “hop”.� Source and destination address – carried within the IP header.� The router looks the destination address and forwards the packet to the next

hop.� We distinguish between packet routingpacket routing and packet forwardingpacket forwarding:

�� ForwardingForwarding – sending the packet from one router to another, based on various params.

�� RoutingRouting – complex process, includes routing info exchange among routers.

� Always follows the same path, regardless of service used.� No guaranted QoS!� Within one backbone, QoS can be controlled using various mechanisms:

� On MPLS backbones – by defining various QoS classes and using DiffServ.� On pure IP backbones – queueing, traffic shaping, per-service rate limiting.

�� Between two different ISP backbones Between two different ISP backbones –– no guarantees for no guarantees for QoSQoS at all!at all!

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Need for QoS� Users experience packet loss, delays etc.

� Routers – need some time for processing IP packets (forwarding) ...

� Routing – always follows the same path, regardless of service used ...

� Some Internet services are delay or throughput sensitive:� File-transfer oriented services, like Web, Ftp, Usenet etc. – need throughput!

� VoIP, Real video/audio and other interactive services are delay-sensitive!

� For voice – delays over 100 ms cause a significant degradation!

� Customers need firm QoS agreement with their ISP’s.

�� Service level agreements (SLA)Service level agreements (SLA):� Defined between the customer and their ISP.

� May include strict boundaries on delay, throuput, (un)availability etc.

� Care must be taken to define realistic values, within the laws of physics:� RTT of 80-90 ms over transatlantic trunks is a realistic value.

� RTT of 40 ms over transtlantic trunks is not realistic (speed of light !!!).

What can an ISP do about it?What can an ISP do about it?

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New York London

ParisWash DC

Source

Destin

New York London

ParisWash DC

Source

Destin

Routing Between Backbones

Hot potato routing:Hot potato routing:� Popular in early days of Internet (NSFNET).

� Principle – get rid of the packet ASAP.

� Give the packet away at the first possible hop to the peering partner

� Advantage if backbone capacities are a problem.

� Disadvantage, if strict QoS control is needed.

Cold potato routing:Cold potato routing:• Preferred strategy nowadays

• Principle – keep the packet within your own backbone as long as possible.

• Advantage, better QoS control!

• Disadvantage, if backbone capacities are a problem.

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Internet Services� Services are:

� The main raison d’etreraison d’etre of any telecommunications networkof any telecommunications network.� Traffic generators and bandwidth consumers !!!� Drivers of network development and growth ...� Revenue generators for service providers.

� From the technical point of view:� All services use TCP/IP protocol suite as the underlying communications engine.� All services follow the same client-server communication principle.

� Services are a matter of the contract between the ISP and user.� The ISP reserves the right to restrict some services by AUP, additional fees etc.

� So far, we used to talk about classical Internet services:� Email, Web, Telnet – derived from simple applications

� Today, we must talk about valuevalue--addedadded services:� Services for residential customers (home business and fun).� Services for business customers (corporate solutions).� All value-added services based on classical Internet services.

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Basic Services

�� Term Term services services here is equal to specific Internet appliances and applications.here is equal to specific Internet appliances and applications.�� Basic services Basic services –– accessible almost everywhere in the accessible almost everywhere in the Net.worldNet.world::

Electronic mail (Electronic mail (email, email, gmailgmail, yahoo mail, yahoo mail))Information store and retrieval (Information store and retrieval (Web, ftp, cloudWeb, ftp, cloud))Chat and interactive games (Chat and interactive games (ViberViber, Twitter, Twitter))OnOn--line discussion (line discussion (UsenetUsenet, , mailing lists, blogsmailing lists, blogs))Unified communications (Unified communications (Skype, Skype, GTalkGTalk, , WebexWebex,…,…))Net.broadcastingNet.broadcasting ((YouTube, Netflix, YouTube, Netflix, webTVwebTV))Interactive access to remote hosts (Interactive access to remote hosts (telnettelnet, , sshssh))

�� ValueValue--added services:added services:Telecommuting (access to corporate servers and services from home)Telecommuting (access to corporate servers and services from home)Distance learning (broadcasts of academic lectures, vendor courses etc.)Distance learning (broadcasts of academic lectures, vendor courses etc.)Online shoppingOnline shoppingSmall LAN (SOHO) interconnectionSmall LAN (SOHO) interconnectionComputerComputer--telephony and computertelephony and computer--TV integration (Internet access from TV TV integration (Internet access from TV etcetc.).)

ValueValue--added services are based on one or more basic servicesadded services are based on one or more basic services(e.g. E(e.g. E--commerce is mostly based on commerce is mostly based on WebWeb))

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C&W global cable systems

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C&W USA cable systems

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C&W – Europe cable systems

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C&W – UK cable systems

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C&W – Asian network

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SPRINT – Europe network

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SPRINT SPRINT –– USA networkUSA network

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SPRINT – Asia network

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Cogent USA – world network

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Global Internet Map

october 2009.

dr Nenad Krajnović

Elektrotehnički fakultet u Beogradu

E-mail: krajko@etf.bg.ac.rs