The ARPANET početak...

Transcription

1 dr Nenad Krajnović Elektrotehnički fakultet u Beogradu krajko@etf.bg.ac.rs The ARPANET početak... Growth of the ARPANET (a) December (b) July (c)march (d) April (e) September

2 Interconnection of Backbone ISP Networks NAP IXP 4 Path Choice 0.5$/MB NAP IXP = 0.25 $/MB 5 Commercial Impact on the Global Network There is no such thing as global backboneany more! There is no such thing as Internet coreany more! Backboneof 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! 6 2

3 Network Access Pointsand 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, Major European NAPs: DE-CIX - Frankfurt am Main AMS-IX Amsterdam LINX London Netnod Stockholm, Malmo, Sundsvall... SOX Serbian Open Exchange ixps/ 7 Traffic on DE-CIX 8 Arhitektura DE-CIX-a 9 3

4 Traffic on LINX Arhitektura LINX-a (2016.) I deo 11 Arhitektura LINX-a (2016.) II deo 12 4

5 Traffic on AMS-IX Arhitektura AMS-IX-a (2016.) 14 Traffic on Netnod

6 Traffic on Seattle IX Architecture of Seattle IX 17 Traffic on NYIIX

7 Traffic on SOX Access Networks - Overview 20 Backbone Technologies LAN technologies (PoPs, NAPs): Fast and Gigabit Ethernet (0.1-1Gbps) 1Gbps) almost ultimate PoPLAN technologies today. 10Gbps Ethernet developed, implemented on biggest sites. 100Gbps Ethernet new standard for high demand sites. WAN technologies (backbone lines): Long-haul Gigabit, 10G Ethernet and 100G Ethernet Mostly metropolitain area. On xwdm optical transport networks Gigabit and 10G Ethernet can be offered in WAN networks. 21 7

8 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 transit-free). They interconnect their network (for free!) with other backbone ISP s. Interconnection between backbones is usually called peering. Peeringcan be: Public implementing by bringing backbone routers to the public IX/NAP s. Private usually a leased line or local cable between two backbones. 22 Internet Routing Protocol responsible for routing is IP (Internet Protocol). Connectionless! Based on hop-by-hop 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 routing and packet forwarding: Forwarding sending the packet from one router to another, based on various params. Routing 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 no guarantees for QoSat all! 23 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): 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 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? 24 8

9 Routing Between Backbones Source 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: 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. New York Wash DC Destin New York Wash DC London Paris London Paris Source Destin 25 Internet Services Services are: The main raison d etre of 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: , Web, Telnet derived from simple applications Today, we must talk about value-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. 26 Basic Services Term services here is equal to specific Internet appliances and applications. Basic services accessible almost everywhere in the Net.world: Electronic mail ( , gmail, yahoo mail) Information store and retrieval (Web, ftp, cloud) Chat and interactive games (Viber, Twitter) On-line discussion (Usenet, mailing lists, blogs) Unified communications (Skype, GTalk, Webex,, ) Net.broadcasting (YouTube, Netflix, webtv) Interactive access to remote hosts (telnet, ssh) Value-added added services: Telecommuting (access to corporate servers and services from home) Distance learning (broadcasts of academic lectures, vendor courses etc.) Online shopping Small LAN (SOHO) interconnection Computer-telephony telephony and computer-tv integration (Internet access from TV etc.) Value-added added services are based on one or more basic services (e.g. E-commerce is mostly based on Web) 27 9

10 C&W global cable systems 28 C&W USA cable systems 29 C&W Europe cable systems 30 10

11 C&W UK cable systems 31 C&W Asian network 32 SPRINT Europe network 33 11

12 SPRINT USA network 34 SPRINT Asia network 35 Cogent USA world network 36 12

13 Global Internet Map october dr Nenad Krajnović Elektrotehnički fakultet u Beogradu krajko@etf.bg.ac.rs 13