Intro to BGP All-Day TutorialIndexSlide 3Slide 4Internet Connectivity OverviewHaving Internet ConnectivityMultihoming Without BGPMultihoming Without BGPBGP Route Advertisement (1)BGP Route Advertisement (2)BGP Route Advertisement (3)BGP Route Advertisement (4)Multihoming Without BGP - How it WorksCustomer Side - OutboundCisco Load BalancingCustomer Side - InboundProvider Side (1)Provider Side (2)Address Space ComplicationsDisadvantages of not using BGPWhy BGP?What is BGP?BGP is … (1)BGP is … (2)Purpose of BGPSlide 26Basic BGP ConceptsBasic BGP Concepts (1)BGP AND ASNsBasic BGP Concepts (2)Basic BGP Concepts (3)Basic BGP Concepts (4)CISCO DIAGRAM - RIB FIB ETCBasic BGP Concepts - The BGP Route and Route AttributesThe BGP RoutePowerPoint PresentationSlide 37Slide 38Slide 39Slide 40Slide 41Slide 42MED Attribute (2)Slide 44Origin AttributeSlide 46Weight Attribute (ctd)Slide 48Local-Pref Attribute (2)iBGP vs. eBGPSlide 51iBGPeBGP (1)eBGP (2)Slide 55eBGP RulesiBGP RulesSlide 58iBGP Restriction (1)iBGP Restriction (2)iBGP and next-hop (1)iBGP and next-hop (2)Basic BGP Concepts Inserting Routes into BGPInserting Routes into BGP (1)Inserting Routes into BGP (2)Inserting Routes into BGP (3)Inserting Routes into BGP (4)Basic BGP Advertising RoutesBGP Peering Sessions (1)BGP Peering Sessions (2)Peering - BGP State MachinePeering - Processing RoutesFiltering BGP Routes - BGP Policy ControlBGP Policy ControlSlide 75Slide 76Slide 77Slide 78Cisco Regular Expressions (1)Cisco Regular Expressions (2)Cisco Regular Expressions (3)Slide 82Slide 83Route Maps (1)Route Maps (2)Route Maps (3)Route Maps (4)Route Maps (5)Basic BGP Selecting RoutesSelecting BGP RoutesSelecting BGP Routes - BasicSlide 92Hardware for BGPRouter Vendors (1)Router Vendors (2)Router Vendors (3)Router Vendors (4)Cisco ProductsMultihoming with BGP An IntroductionStep 1 - Determine PolicyPolicy for Basic Multi-HomingWarning - I am Blackholio (1)Warning - I am Blackholio (2)Warning - I am Blackholio (3)Multihoming - Minimal BGP (for cheap routers)Insert Static Default RoutesGather NetworksSet up BGP Base ConfigConfiguring Neighbors - NoteNeighbor Configuration (1)Neighbor Configuration (2)Test itMultihoming with BGP - Taking Customer Routes (an intermediate solution)Taking Just Customer RoutesTaking Just Customer Routes (2)Taking Just Customer Routes (3)Taking Just Customer Routes (4)Multihoming with BGP - Taking Full RoutesPolicySo, what Policy?Configuring Full BGPLogistics of becoming MultihomedMultihoming LogisticsMultihoming to the same ProviderSlide 125The Network Grows - Supporting BGP CustomersSupporting BGP Customers (1)Supporting BGP Customers (2)Supporting BGP Customers (3)Hot Potato vs. Hop-by-Hop RoutingHot Potato RoutingQuickie on Route-MapsImplementing CommunitiesSlide 134TUNING INBOUND BGP ANNOUNCEMENTSInbound BGP RoutesTuning Inbound BGP RoutesSlide 138Slide 139Slide 140Slide 141Slide 142TUNING OUTBOUND BGP ANNOUNCEMENTSTuning Outbound BGPTuning Outbound - PaddingSlide 146Tuning Outbound - CommunitiesTuning Outbound - deagg.PEERING WITH OTHER ISPSPeeringPEERING AND next-hop-selfBGP: Next-hop-selfNext-Hop-Self Issues: BadNext-Hop-Self Issues: BetterBACKUP TRANSITSTABLE BGPStable BGPStable BGP - LoopbacksBGP Stability - soft-reconfigSlide 160eBGP MultihopSlide 162Blackhole w/ eBGP MultihopSUPPORTING MULTI-HOMED CUSTOMERSSupporting Multi-Homed CustsSlide 166IGP REDISTRIBUTIONSCALING WITH CONFEDERATIONSBGP ConfederationsLogical View of full 16-router MeshConfederationsAS-Path filters for confederationsSCALING WITH ROUTE REFLECTORSSlide 174Other IssuesAccess-List 112: smdCISCO CONFIGURATIONIntro to BGPIntro to BGPAll-DayAll-DayTutorialTutorialAvi FreedmanAvi [email protected]@netaxs.comIndex•Internet Connectivity Overview•Multihoming Concepts•Multihoming Without BGP•Multihoming - Address Space ComplicationsIndex•Basic BGP - The BGP Route•Basic BGP - Inserting Routes into BGP•Basic BGP - Advertising Routes•Basic BGP - Other BGP Route Attributes•Basic BGP - Selecting RoutesIndex•Multihoming with BGP - an Introduction•Interlude - Hardware for BGP•Multihoming with BGP with a Cheap Router•Multihoming with BGP - Taking Just Customer Routes•Multihoming with BGP - Taking Full Routes•Default Routing in BGPInternet Internet ConnectivityConnectivityOverviewOverviewHaving Internet ConnectivityHaving Internet Connectivity•To have complete Internet connectivity you must be able to reach all destinations on the net.•Your packets have to get delivered to every destination. This is easy (default routes).•Packets from everywhere else have to “find you”. This is done by having your ISP(s) advertise routes for you.Multihoming Multihoming WithoutWithoutBGPBGPMultihoming Without BGPMultihoming Without BGP•To get Internet connectivity, you can just default route your traffic to your upstream providers.•To get traffic back from the Internet, you need to have your providers tell all of the rest of the Internet “where you are”.BGP Route Advertisement (1)BGP Route Advertisement (1)•Think of a BGP route as a “promise”.•If I advertise 207.8.128.0/17, I promise that if you deliver traffic to me for anywhere in 207.8.128.0/17, I know how to deliver it at least as well as anyone else.•If my customer has 207.8.140.0/24, I generally will not announce that route separately since it is covered by my 207.8.128.0/17 aggregate route.BGP Route Advertisement (2)BGP Route Advertisement (2)•By making sure these routes, or “promises”, are heard by ALL providers on the ‘net, your provider ensures a return path for all of your packets.•Remember, sending packets OUT is easier than getting them back.•Also, remember - sending routes OUT causes IP traffic to come IN.BGP Route Advertisement (3)BGP Route Advertisement (3)•But the most specific route wins, so if one of my customers’ ISPs is advertising 207.8.240.0/24, all incoming traffic from other networks will start flowing in that pipe.•So I must “punch a hole” in my aggregate announcement and advertise 207.8.128.0/17 and 207.8.240.0/24.BGP Route Advertisement (4)BGP Route Advertisement (4)•The complete set of routes advertised by all BGP speakers on the net is about 55,000 routes as of 10/98. •If your route is missing in the “view” of any major provider, you will not have connectivity to them.Multihoming Multihoming Without BGP -Without BGP -How it WorksHow it WorksCustomer Side - OutboundCustomer Side -