Hálózati és Szolgáltatási Architektúrák

Átírás

1 Hálózati és Szolgáltatási Architektúrák Architectures of Networks and Services Mérnök informatikus szak, MSc képzés Hálózatok és szolgáltatások szakirány 2. alkalom február 16., Hétfı, IB.138, 8:30-10:00 Dr. Cinkler Tibor cinkler()tmit.bme.hu Egyetemi Docens BME TMIT Dr. Vidács Attila Egyetemi Docens BME TMIT TMIT: Távközlési és Médiainformatikai Tanszék

2 Router (/'rautər/ in the USA and Canada, /'ru:tə/ in the UK and Ireland) Core and Edge Internet core link speeds are 10 Gbit/s (STM-64, OC-192, STS-192) 40 Gbit/s (STM-256, OC-768, STS-192) ISP: Internet Service Provider A company that offers its customers access to the Internet Interconnected physically, running BGP Autonomous System (AS) is a collection of connected IP routing prefixes under the control of one or more network operators that presents a common, clearly defined routing policy to the Internet, cf. RFC 1930, Section 3. PoP: an artificial demarcation point or interface point between communications entities Internet exchange points (IX, IXP, régen NAP: Network Access Point) colocation centres Single-Homing, Dual-Homing, Multi-Homing A multihomed Autonomous System is an AS that maintains connections to more than one other AS. 32

3 Routers Provider Edge Router: Placed at the edge of an ISP network, it speaks external BGP (ebgp) to a BGP speaker in another provider or large enterprise Autonomous System (AS). Subscriber Edge Router: Located at the edge of the subscriber's network, it speaks ebgp to its provider's AS(s). It belongs to an end user (enterprise) organization. Inter-provider Border Router: Interconnecting ISPs, this is a BGP speaking router that maintains BGP sessions with other BGP speaking routers in other providers' ASes. Core router: A router that resides within the middle or backbone of the LAN network rather than at its periphery. 33

4 Edge Router From SOHO (Small Office Home Office) to Enterprise Routers 34

5 Core Router A core router is a router designed to operate in the Internet backbone, or core. able to support multiple telecommunications interfaces of the highest speed in use in the core Internet and must be able to forward IP packets at full speed on all of them. It must also support the routing protocols being used in the core. Core router manufacturers Alcatel-Lucent Avici Systems Cisco Systems Huawei Technologies Ltd. Juniper Networks Nortel Networks 35

6 Core Routers Source: 36

7 Core Routers Source: Terabit Switch cluster 3 configurations: 8003, a 3-slot chassis most commonly used for access or distribution / aggregation of switches; 8006, a 6-slot chassis for backbones of low density or high space premium; 8010, a 10-slot chassis for high availability and high scalability. 37

8 Transit vs. Peering Peering is voluntary interconnection of administratively separate Internet networks for the purpose of exchanging traffic between the customers of each network. The pure definition of peering is settlement-free or "sender keeps all" meaning that neither party pays the other for the exchanged traffic, instead, each derives revenue from its own customers. Two networks exchange traffic between each other's customers freely, and for mutual benefit. Transit provider: pay money (or settlement) to another network for Internet access (or transit) Only ISPs as customer Charge transit fee 38

9 Transit vs Peering ( 39

10 Tier 1, 2, 3 ISPs Source: api.ning.com 40

11 ISP hierarchy: Tier 1, Tier 2, Tier 3 Tier 1 networks are those networks that don't pay any other network for transit yet still can reach all networks connected to the internet. A Tier 1 is constantly faced with customers trying to bypass it, and this is a threat to its business. (de-peering). ( A Tier 2 Network is an Internet service provider who engages in the practice of peering with other networks, but who still purchases IP transit to reach some portion of the Internet. Tier 3 is sometimes also used to describe networks who solely purchase IP transit from other networks (typically Tier 2 networks) to reach the Internet. Single or Dual Homing. (depeering) Nice maps at: 41

12 ISP hierarchy: Tier 1, Tier 2, Tier 3 Tier 1 networks usually have only a small number of peers (typically only other Tier 1s and very large Tier 2s), while Tier 2 networks are motivated to peer with many other Tier 2 and enduser networks. Thus a Tier 2 network with good peering is frequently much "closer" to most end users or content than a Tier 1. By definition, there are networks which Tier 1 networks have only one path to, and if they lose that path, they have no "backup transit" which would preserve their full connectivity. Some Tier 2 networks are significantly larger than some Tier 1 networks, and are often able to provide more or better connectivity. Only Tier 3 networks (who provide Internet access) are true "resellers", while many large Tier 2 networks peer with the majority or even vast majority of the Internet directly except for a small portion of the Internet which is reached via a transit provider. ( 42

13 Tier 1 Networks The 9 Tier 1 Networks ( The 10th Tier 1 Network? 43

14 -viewer-ipv4-top jpg 44

15 Sőrőbb virtuális vagy logikai topológia A probléma szemléltetése fizikai hálózat 2. virtuális utak rendszere 3. virtuális topológia 45

16 Pl. hullámhossz-rendszer segítségével 46

17 Horizontal and Vertical structure Horizontal: Transit: Acces/Aggregation Metro Core Tier3 Tier2 Tier1 Peering: Multi-Domain Peering Multi-Vendor Multi-Provider Multi-Service Multi-Region Vertical: Interconnection or Integration Multi-Provider Multi-Service Multi-Region 47

18 Függıleges Tagoltság: Többrétegő hálózatok Egy rétegő hálózat: Gyenge granularitás: 1 fényszál: 1-10 Tbit/s (DWDM: λ) 1 λ csatorna: 2.5 vagy 10 Gbit/s 1 STM-64: 64 x STM-1 További rétegek a finomabb granularitáshoz Több rétegő hálózat: Bonyolult vezérlés és Menedzsment (Control & Management) Útvonalválasztás (Routing) Forgalomterelés (TE: Traffic Engineering) Hibatőrıképesség (Resilience) Kétszerezett vagy többszörözött funkciók 48

19 Beszéd, adat, adattárolás és video a nyilvános szállítóhálózaton Forrás: E.H. Valencia, M. Scholten, Z. Zhu: GFP, IEEE Communications Magazine May 2002 * Fényszálon közvetlenül is 49

20 Többrétegő adatátviteli architektúra Forrás: M. Scholten, Z. Zhu, E.H. Valencia, J. Hawkins: GFP, IEEE Communications Magazine May

21 Mi a forgalom-kötegelés (Traffic Grooming)? C A B D C A B D C A B D 51

22 GMPLS/ASTN Dinamikus (Kapcsolt) és Többrétegő Dynamic (switched) & Multilayer IETF GMPLS: Generalised Multiprotocol Label Switching ITU-T ASTN: Automatic Switched Transport Network PSC L2 TSC λsc WBSC FSC (Packet Switching Capable, e.g., IP) (Layer 2 SC, e.g., GbEth) (TDM SC, e.g., SDH VC-4-4c) (Wavelength SC) (WaveBand SC) (Fiber SC) Számítógép hálózatok 25. alkalom vége. 52

23 Általánosított felülcimkézés Generalised Label Stacking Többrétegő architektúra Általánosított LSP-k Multilayer Architecture Generalised LSPs LSP λ fényszál fénykábel 53

24 Label Stacking or Swapping? Cimkecsere, vagy felülcímkézés? LSP4 LSP3 LSP2 LSP1 LSP4 LSP1 LSP2 data Stacked Headers LSP3 54