Internet The value of Internet is in global reachability - PowerPoint PPT Presentation

Lic.(Tech.) Marko Luoma (1/28) Lic.(Tech.) Marko Luoma (2/28) Internet The value of Internet is in global reachability � � Reachability comes from co-operative peering efforts � Customer peering (Customer-Provider-Customer relationship) S-38.192 Verkkopalvelujen tuotanto � Shared cost peering (Provider-Provider relationship) S-38.192 Network Service Provisioning There are roughly 18000 players � � 13000 of them are Stub ASs Lecture 7: Peering � 78 are pure transit providers � 5000 do both Part of the material presented in these slides is based on BGP lectures of Olivier Bonaventure www.info.ucl.ac.be/people/OBO/BGP/ Lic.(Tech.) Marko Luoma (3/28) Lic.(Tech.) Marko Luoma (4/28) Internet Internet The structure of Internet is chaos How packet finds its route Why accepting packets from � � � through the black box fellow ISP � Thousands of service providers with highly varying principles in their operation � BGP forms a structured layout � Economic impact of the whole Internet for � Transit traffic packet level transport � Reciprocity ISP � Reflects the semi-optimal ISP � Cost reduction contractual agreements ISP ISP between operators along ISP ISP the route of the packet ISP ISP ISP ISP ISP ISP ISP ISP ISP ISP

Lic.(Tech.) Marko Luoma (5/28) Lic.(Tech.) Marko Luoma (6/28) Agreements Strict hierarchy Form the basis between inter-provider communications � � Small ISPs are customers of larger ones ISP � Larger ISPs deliver their customer traffic as their own traffic � Larger ISPs deliver their customer traffic as transit traffic � Equal size providers exchange their traffic pro bonus ISP ISP � Both save money by interconnecting directly rather than through 3 rd party � Mutual agreement for exchanging only their customer traffic ISP ISP ISP ISP ISP ISP ISP Lic.(Tech.) Marko Luoma (7/28) Lic.(Tech.) Marko Luoma (8/28) Strict hierarchy Loose hierarchy Based on structural and regulated manner of forming customer/provider � relationships � Valid in telco operations ISP � Operators for a chain of customer/provider relationships � Based on regulation of operational arena ISP ISP � Local operators � Long distance operators � International operators ISP ISP ISP � Cash flows to the top of the hierarchy � Local operators collect the money from end users � Middle layers take their premiums ISP ISP ISP ISP

Lic.(Tech.) Marko Luoma (9/28) Lic.(Tech.) Marko Luoma (10/28) Loose hierarchy Internet Local providers compete the local market but share common need to Naturally loose in hierarchy � � exchange their customer traffic on a local level Local ISPs maximize their revenue by minimazing their transit traffic � � It is profitable for all to have direct exchange of traffic without 3 rd Same structure on all levels of hierarchy � parties Any connection through the Internet is formed with chain of � � Better marginal revenue customer/provider relationships with a single zero payment border � Requires � Cost of connection is therefore divided into two � Interconnection points � From source to top of the chain � Bilateral agreement to establish equality � From destination to top of the chain � Zero payment principle � Peering does not cover transit traffic � Both parties benefit from peering � Only one zero payment border � No mutual transfer of money Lic.(Tech.) Marko Luoma (11/28) Lic.(Tech.) Marko Luoma (12/28) Internet Transit domain A transit domain allows external domains to use its own infrastructure to � send packets to other domains Cost Area A Zero payment ISP T2 T1 S4 S1 ISP ISP ISP T3 S2 S3 ISP Examples � Cost Area B � FuNET, NorduNET, GEANT, Internet2, BT, Telia, Level3,...

Lic.(Tech.) Marko Luoma (13/28) Lic.(Tech.) Marko Luoma (14/28) Stub domain Stub domain A stub domain does not allow external domains to Examples: � � use its infrastructure to send packets to other domains � Content-rich stub domain � A stub is connected to at least one transit domain � Large web servers : Yahoo, Google, MSN, TF1, BBC,... � Single-homed stub : connected to one transit domain (S1) � Access-rich stub domain � Dual-homed stub : connected to two transit domains (S2-S4) � ISPs providing Internet access via CATV, ADSL, ... � Saunalahti, Kolumbus, Welho etc T2 T1 S4 S1 T3 S2 S3 Lic.(Tech.) Marko Luoma (15/28) Lic.(Tech.) Marko Luoma (16/28) Internet Tier-1 service providers Tier-1 ISPs AOL Transit Data Network Optus � � � � Dozen of large ISPs AT&T Primus Telecom � � interconnected by shared-cost BBN Qwest � � peering arrangements British Telecom Sprint � � � Form the core of the Internet Cable and Wireless Telstra � � � Provide transit service for Connect Internet Solutions UUNET T2/T3 service providers � � Deutsche Telekom WilTel (Williams � � Communications) Global Crossing � Level 3 � NTT/Verio �

Lic.(Tech.) Marko Luoma (17/28) Lic.(Tech.) Marko Luoma (18/28) Internet Internet Tier-2 ISPs Tier-3 ISPs � � � Regional or National ISPs � Smaller ISPs, Corporate Networks, Content providers � Customer of T1 ISP(s) � Customers of T2 or T1 ISPs � Provider of T3 ISP(s) � shared-cost with other T3 � shared-cost with other T2 ISPs ISPs Lic.(Tech.) Marko Luoma (19/28) Lic.(Tech.) Marko Luoma (20/28) Customer-provider peering Shared-cost peering � Principle � Principle � Customer sends to its provider its internal routes and the routes � PeerX sends to PeerY its internal routes and the routes learned learned from its own customers from its own customers � Provider will advertise those routes to the entire Internet to � PeerY will use shared link to reach PeerX and PeerX's allow anyone to reach the Customer customers � Provider sends to its customers all known routes � PeerX's providers are not reachable via the shared link � Customer will be able to reach anyone on the Internet � PeerY sends to PeerX its internal routes and the routes learned from its own customers AS1 AS2 � PeerX will use shared link to reach PeerY and PeerY's $ $ $ customers Customer Provider $ � PeerY's providers are not reachable via the shared link AS3 AS4 $ AS7

Lic.(Tech.) Marko Luoma (21/28) Lic.(Tech.) Marko Luoma (22/28) Shared-cost peering Internet AS1 send routes of AS{1,3,4,7} to AS2 Local providers aim to minimize their expenses by interconnecting � � at local level AS2 sends routes of AS{2,4,7} to AS1 � � Local exchange points � Not AS3 while those routes come from shared-cost peering � ..CIX (Commercial Internet eXchange) � Routes from shared-cost peering are not advertised to providers � MAE.. (Metropolitan Area eXchange) � NAP (Network Access Point) AS1 AS2 � IXP (Internet eXchange Point) � EP (Exchange Point) $ $ $ Shared-cost � Bilateral interconnections Customer provider AS3 AS4 $ $ AS7 Lic.(Tech.) Marko Luoma (23/28) Lic.(Tech.) Marko Luoma (24/28) Internet exhange Internet exhange Commercial starting point Build over L2 technology � � � A company builds an interconnection point to � Ethernet, ATM, FrameRelay switch � Gain revenue from peering traffic Each provider connects into shared media with transmission link � � Gain revenue from transmission links coming to exchange terminated to border router of provider � Gain revenue from transit traffic � Everybody is able to see everybody Co-operative starting point � � Neutral partner runs the exchange ISP ISP � None of the partners owns the premises � None of the partners owns the transmission links into exchange � None of the partners owns the equipment in exchange ISP ISP

Lic.(Tech.) Marko Luoma (25/28) Lic.(Tech.) Marko Luoma (26/28) Internet exhange Internet exhange � Bilateral agreements Peering agreements can be based on � � Multilateral agreements � Partners peer only based on bilateral agreements � Requires L2 technology that is able to create virtual � Every partner is peering with every other partner connections between peering partners � All border routers share a common subnet which is not � ATM PVC filtered � FR DLCI � Ideal situation for Ethernet type of IXP solution � Ethernet VLAN ISP ISP ISP ISP ISP ISP ISP ISP Lic.(Tech.) Marko Luoma (27/28) Lic.(Tech.) Marko Luoma (28/28) Internet exhange Internet exhange Multilateral peering reguires either Depending on operational philosphy of IXP � � � Separate BGP session between each border router � Partners can make bilateral transit agreements in IXP � N(N-1) sessions � Partners are already in same premises � IXP offers route server capabilities � Required separate virtual connections between transit provider and customer � Only N sessions � Partners can make QoS peering � BGP-route reflector � Several virtual connections between peers � One per VPN per QoS class � One per MPLS LSP � etc