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., Szerda, IB.140, 8:15-10: 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. 42

3 Colocation center a type of data centre where multiple customers locate network, server and storage gear and interconnect to a variety of telecommunications and other network service provider(s) with a minimum of cost and complexity. Most Internet exchange points provide colocation. Advanteges shared data centre infrastructure cheaper Lower latency faster access Greater bandwidth 43

4 Kiknek kell kolokációs központ? Major types of colocation customers are: Web commerce companies, who use the facilities for a safe environment and costeffective, redundant connections to the Internet Major enterprises, who use the facility for disaster avoidance, offsite data backup and business continuity Telecommunication companies, who use the facilities to interexchange traffic with other telecommunications companies and access to potential clients Követelmények: Hőtés, főtés, páratartalom, tőzvédelem, beléptetı rendszer, redundáns táp, statikus elektromosság védelem, stb. 44

5 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. 45

6 Edge Router From SOHO (Small Office Home Office) to Enterprise Routers 46

7 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 47

8 Core Routers Source: Cisco CRS-1 16-Slot Single-Shelf System is a massively scalable routing system that integrates multiple POP functions while providing the service flexibility, continuous system operation, and system longevity of the Cisco CRS-1 platform in a full-height configuration. The Cisco CRS-1 16-Slot Single-Shelf System: Consists of a single, 16-slot, 40-Gbps-perslot line-card shelf for a total switching capacity of 1.2 Tbps Features a midplane design based on a linecard shelf built from a line-card chassis Protects investments by using modular services cards (MSCs) and physical layer interface modules (PLIMs) that are fully interchangeable across the CRS-1 product family Contains slots for 16 MSCs and eight fabric cards in the rear of the chassis, and 16 PLIMs, two route processors or additional distributed route processors, and two fan controllers in the front of the chassis Accommodates eight fabric cards in the rear of the chassis, which perform Stage 1, Stage 2, and Stage 3 switching, supporting service-intelligent fabric-based queuing and multicast replication 48

9 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. 49

10 Transit vs. Peering Internet architektúra lényege 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 50

11 Depeering peering is the voluntary and free exchange of traffic between two networks, for mutual benefit. If one or both networks believes that there is no longer a mutual benefit, they may decide to cease peering: this is known as depeering. Some of the reasons why one network may wish to depeer another include: A desire that the other network pay settlement, either in exchange for continued peering or for transit services. A belief that the other network is "profiting unduly" from the settlement free interconnection. Concern over traffic ratios, which related to the fair sharing of cost for the interconnection. A desire to peer with the upstream transit provider of the peered network. Abuse of the interconnection by the other party, such as pointing default or utilizing the peer for transit. Instability of the peered network, repeated routing leaks, lack of response to network abuse issues, etc. The inability or unwillingness of the peered network to provision additional capacity for peering. The belief that the peered network is unduly peering with your customers. Various external political factors (including personal conflicts between individuals at each network). 51

12 Transit vs Peering ( 52

13 Tier 1, 2, 3 ISPs Source: api.ning.com 53

14 Tier 1, 2,

15 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: 55

16 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. ( 56

17 Tier 1 Networks The 9 Tier 1 Networks ( The 10th Tier 1 Network? 57

18 Tier 1 Networks 1 évvel késıbben... The 12th Tier 1 Network? 58

19 -viewer-ipv4-top jpg 59

20 ISP osztályozás Kovács Tamás Majdán András a szolgáltatók Tier besorolása nem triviális Tier1 besorolás egyszerő megközelítése: o nagy forgalom o nagy kapacitás o széles vásárlókör o nagy számú AS a hálózatban Nem a méret a lényeg: hozzáférnek a teljes routing táblához 1 vagy 2 AS kontinensenként, ideális esetben 1 világszerte nemzetközi üvegszálas hálózat adatcsere vásárlókkal és peer-ekkel az egész világon 60 60

21 ISP osztályozás caida.org Kovács Tamás Majdán András CAIDA, the Cooperative Association for Internet Data Analysis, provides tools and analyses promoting the engineering and maintenance of a robust, scalable global Internet infrastructure. Saját szempontrendszer szerint rangsorolt ISP-k 61 61

22 ISP osztályozás caida.org Kovács Tamás Majdán András

23 ISP osztályozás caida.org Egy szkript segítségével kétféle módon végzik: degree based AS based Kovács Tamás Majdán András Metric Ases Description number of ASes in the customer cone (ASes that can be reached from a given AS by following c2p links first through to its customers, then on to its customers' customers, and so on) Prefixes number of unique prefixes announced by all ASes in the customer cone /24 number of unique /24 prefixes in the IP address space covered by the customer cone Degree number of unique ASes connected to this AS via any kind of links (p2c, c2p, p2p, or s2s) 63 63

24 Kovács Tamás Majdán András

25 Level3 Kovács Tamás Majdán András Nemrégiben a Renesys Észak-Amerika és Európa elsıszámú szolgáltatójának minısítette A világ legnagyobb, legfejlettebb Tier1 Telco hálózatát üzemelteti A Renesys az elsı 10 ázsai szolgáltató közé sorolta CAIDA az elsı számú ISPnek rangsorolta 65 65

26 Kovács Tamás Majdán András

27 Verizon Kovács Tamás Majdán András ben jött létre a Bell Atlantic és a GTE egyesülésével Globális IP hálózata 446 ezer mérföld 2700 város, 150 ország 6 kontinensen A hálózat sebessége OC-192 kategóriájú Az elsı 10 legnagyobb ISP szolgáltató közé tartozik

28 Kovács Tamás Majdán András Forrás: isp-planet.com 68 68

29 Sprint Kovács Tamás Majdán András A világ egyik legnagyobb Tier1 hálózata A gerinchálózaton több AS hálózati kapcsolat, mint bármely másikon Nagysebességő összeköttetések (OC- 192/STM64) 1. számú ISP Ázsiában, 2. Európában, Észak- Amerikában

30 Sőrőbb virtuális vagy logikai topológia A probléma szemléltetése fizikai hálózat 2. virtuális utak rendszere 3. virtuális topológia 70

31 Pl. hullámhossz-rendszer segítségével 71

32 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 72

33 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 73

34 Hálózati és Szolgáltatási Architektúrák Architectures of Networks and Services Mérnök informatikus szak, MSc képzés Hálózatok és szolgáltatások szakirány 4. alkalom március 2., kedd, IB.138, 10:15-12:00 Dr. Cinkler Tibor cinkler()tmit.bme.hu Egyetemi Docens BME TMIT TMIT: Távközlési és Médiainformatikai Tanszék

35 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 75

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

37 Mi a forgalom-kötegelés (Traffic Grooming)? C A B D C A B D C A B D 77

38 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. 78

39 Általánosított felülcimkézés Generalised Label Stacking Többrétegő architektúra Általánosított LSP-k Multilayer Architecture Generalised LSPs LSP λ fényszál fénykábel 79

40 Label Stacking or Swapping? Cimkecsere, vagy felülcímkézés? LSP4 LSP3 LSP2 LSP1 LSP4 LSP1 LSP2 data Stacked Headers LSP3 80

41 Routing, TE & Resilience manapság: Kliens-szerver megoldás Részben kézzel DP n+2 DP n+1 DP n DP n-1 MP n+2 CP n+2 MP n+1 CP n+1 MP n CP n MP n-1 CP n-1 client server client server client server 81

42 Routing, TE & Resilience vágy: Integrált, automatikus, elosztott! Függıleges együttmőködtetés vagy integrálás? DP n+2 DP n+1 MP CP DP n DP n-1 82

43 Multi-Layer (Vertical) Interconnection Models (RFC 3717) Overlay Model The control of layers is independent Server-Client approach like classical IP over ATM or MPOA models optical layer can be statically configured Peer Model Interoperable control plane (e.g., Optical layer is also IP addressable) Augmented (Hybrid) Something between Hides confidential provider information Some information of one routing instance passed through the other E.g., IP addresses could be carried within the optical routing protocol 83

44 Vertical Integration: Multi-Layer Integrated Model The layers owned by the same operator Full interlayer information exchange possible (No interface needed in between) Can be operated by a single CP and a single MP Routing, TE, Resilience more complex MRN: Multi Region Network (Region: interconnected nodes of the same networking technology a bit missleading) 84

45 MLN/MRN Shiomoto, K., Papadimitriou, D., Le Roux, JL., Vigoureux, M., and D. Brungard, "Requirements for GMPLS-Based Multi-Region and Multi-Layer Networks (MRN/MLN)", RFC 5212, July In GMPLS, a switching technology domain defines a region, and a network of multiple switching types is referred to in this document as a multi-region network (MRN). Traffic Engineering Database (TED) Itt van minden infó, ami egy egységes GMPLS síkhoz kell Interface Switching Capability (ISC) - introduced in GMPLS to support various kinds of switching technology in a unified way [RFC4202] Virtual Network Topology (VNT) lower-layer FA-LSP létrehozása: static (pre-provisioned) vagy dynamic (triggered) (FA-LSP: Forwarding Adjacency Label Switched Path) 85

46 MLN/MRN Ed.: JL. Le Roux, D. Papadimitriou, "Evaluation of Existing GMPLS Protocols against Multi- Layer and Multi-Region Networks (MLN/MRN) ", RFC 5339, September 2008 MIB modules model and control of GMPLS switches [RFC4803] control and report on the operation of the signaling protocol [RFC4802] a MIB module for managing TE links [RFC4220] (interesting for MLN!) Oki, E., Le Roux, J-L., and A. Farrel, "Framework for PCE-Based Inter- Layer MPLS and GMPLS Traffic Engineering", Work in Progress, June Miyazawa, M., Otani, T., Nadeau, T., and K. Kunaki, "Traffic Engineering Database Management Information Base in support of MPLS-TE/GMPLS", Work in Progress, July