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Hálózati és Szolgáltatási Architektúrákhttps://www.vik.bme.hu/kepzes/targyak/VITMM130/
Architectures of Networks and Services
Mérnök informatikus szak, MSc képzésHálózatok és szolgáltatások szakirány
Dr. Cinkler Tibor
cinkler()tmit.bme.hu
Egyetemi Docens
BME TMIT
Dr. Vidács Attila
Egyetemi Docens
BME TMIT
2. alkalom
2011. február 16., Szerda, IB.140, 8:15-10:00
http://opti.tmit.bme.hu/~cinkler/HSzA/
http://hsnlab.tmit.bme.hu/~vidacs/education/vitmm131/2009/vitmm131-2009.htm
TMIT: Távközlési és Médiainformatikai Tanszék
42
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 thatpresents 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 (http://en.wikipedia.org/wiki/Point_of_presence)
� Internet exchange points (IX, IXP, régen NAP: Network Access Point)� colocation centres (http://en.wikipedia.org/wiki/Colocation_centre)
� Single-Homing, Dual-Homing, Multi-Homing� A multihomed Autonomous System is an AS that maintains connections
to more than one other AS.
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Colocation center� http://en.wikipedia.org/wiki/Colocation_centre� 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
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Kiknek kell kolokációs központ?Major types of colocation customers are:� Web commerce companies, who use the
facilities for a safe environment and cost-effective, 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.
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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.
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Edge Router
� From SOHO (Small Office Home Office) to Enterprise Routers
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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
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Core RoutersSource: http://upload.wikimedia.org/wikipedia/commons/3/36/Cisco-rs1.jpgCisco 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-per-
slot line-card shelf for a total switching
capacity of 1.2 Tbps
Features a midplane design based on a line-
card 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
http://www.cisco.com/en/US/products/ps5862/index.html
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Core RoutersSource: http://upload.wikimedia.org/wikipedia/en/b/b0/ERS-8600.JPG
1.440 Terabit Switch cluster http://en.wikipedia.org/wiki/Nortel_ERS_8600
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.
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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
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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).
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Transit vs Peering (http://upload.wikimedia.org/wikipedia/commons/thumb/2/2e/AS-interconnection.png/800px-AS-interconnection.png)
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Tier 1, 2, 3 ISPsSource: api.ning.com
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Tier 1, 2, 3 http://en.wikipedia.org/wiki/Tier_1_carrier
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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).
(http://arstechnica.com/old/content/2008/09/peering-and-transit.ars/4)
� 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. (de-peering)
� Nice maps at: http://www.nthelp.com/maps.htm
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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 end-user 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.(http://en.wikipedia.org/wiki/Tier_1_carrier)
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Tier 1 Networks� The 9 Tier 1 Networks (http://en.wikipedia.org/wiki/Tier_1_carrier)
� The 10th Tier 1 Network?
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Tier 1 Networks 1 évvel késıbben...
The 12th Tier 1 Network?
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http://www.usenix.org/events/cset08/tech/full_papers/hazeyama/hazeyama_html/Fig/as-viewer-ipv4-top200-20080107.jpg
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ISP osztályozás
� a szolgáltatók Tier 1-2-3 besorolása nem triviális� Tier1 besorolás egyszerő megközelítése:
o nagy forgalomo nagy kapacitáso széles vásárlóköro 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
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Kovács Tamás – [email protected]án András – [email protected]
2009. 03. 13.
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ISP osztályozás – caida.org„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
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Kovács Tamás – [email protected]án András – [email protected]
2009. 03. 13.
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ISP osztályozás – caida.org
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Kovács Tamás – [email protected]án András – [email protected]
2009. 03. 13.
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ISP osztályozás – caida.org
Egy szkript segítségével kétféle módon végzik:
� degree based
� AS based
Metric Description
Ases 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)
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Kovács Tamás – [email protected]án András – [email protected]
2009. 03. 13.
65
Level3� 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 közésorolta
� CAIDA az elsı számú ISPnek rangsorolta
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Kovács Tamás – [email protected]án András – [email protected]
2009. 03. 13.
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Verizon� 2000-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 közétartozik.
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Kovács Tamás – [email protected]án András – [email protected]
2009. 03. 13.
6868
Forrás: isp-planet.com
Kovács Tamás – [email protected]án András – [email protected]
2009. 03. 13.
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Sprint� 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 4.
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Kovács Tamás – [email protected]án András – [email protected]
2009. 03. 13.
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Sőrőbb virtuális vagy logikai topológiaA probléma szemléltetése
1. fizikai hálózat
2. virtuális utak rendszere
3. virtuális topológia
1. 2. 3.
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Pl. hullámhossz-rendszer segítségével
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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
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Függıleges Tagoltság:Többrétegő hálózatokEgy rétegő hálózat:� Gyenge granularitás:
� 1 fényszál: 1-10 Tbit/s (DWDM: 100-200 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
Hálózati és Szolgáltatási Architektúrákhttps://www.vik.bme.hu/kepzes/targyak/VITMM130/
Architectures of Networks and Services
Mérnök informatikus szak, MSc képzésHálózatok és szolgáltatások szakirány
Dr. Cinkler Tibor
cinkler()tmit.bme.hu
Egyetemi Docens
BME TMIT
4. alkalom
2010. március 2., kedd, IB.138, 10:15-12:00
http://opti.tmit.bme.hu/~cinkler/HSzA/
TMIT: Távközlési és Médiainformatikai Tanszék
75
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
76
Többrétegő adatátviteli architektúra
Forrás: M. Scholten, Z. Zhu, E.H. Valencia, J. Hawkins: GFP, IEEE Communications Magazine May 2002
77
Mi a forgalom-kötegelés (Traffic Grooming)?
A B
C
D
A B D
CA B D
C
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GMPLS/ASTN
Dinamikus (Kapcsolt) és TöbbrétegőDynamic (switched) & Multilayer
IETF GMPLS: Generalised Multiprotocol Label SwitchingITU-T ASTN: Automatic Switched Transport Network
PSC (Packet Switching Capable, e.g., IP)L2 (Layer 2 SC, e.g., GbEth)TSC (TDM SC, e.g., SDH VC-4-4c)λλλλSC (Wavelength SC)WBSC (WaveBand SC)FSC (Fiber SC)
Számítógép hálózatok 25. alkalom vége.
79
Általánosított „felülcimkézés”Generalised Label Stacking
Többrétegő architektúra → Általánosított LSP-k
Multilayer Architecture → Generalised LSPs
fénykábelfényszálλλλλLSP
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Label “Stacking” or “Swapping”?
� Cimkecsere, vagy felülcímkézés?
LSP1LSP2LSP3LSP4
LSP1
LSP2
LSP3
LSP4
dataStacked Headers
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Routing, TE & Resilience →→→→manapság:
DP n+2
DP n+1
DP n
DP n-1
CP n+1
CP n
CP n-1
client
server
client
serverclient
server
CP n+2MP n+2
MP n+1
MP n
MP n-1
Kliens-szerver megoldásRészben kézzel
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Routing, TE & Resilience→→→→ vágy:
DP n+2
DP n+1
DP n
DP n-1
CP
MP
Integrált, automatikus, elosztott!Függıleges együttmőködtetés vagy integrálás?
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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
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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)
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MLN/MRN� www.ietf.org/rfc/rfc5212.txt
� 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 2008. � „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)
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MLN/MRN� www.ietf.org/rfc/rfc5339.txt
� 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 2008.
� 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 2008.
