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Tb2380 retana transitioning from eigrp to ospf_final
 

Tb2380 retana transitioning from eigrp to ospf_final

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  • The original OSPF specification (rfc1131) was published in 1989.OSPFv2 was first published in 1991; it corrected several issues in the initial OSPF specification.rfc2328 is the Standard specification of OSPFv2; published in 1998.OSPF for IPv6 (aka OSPFv3) was first published (rfc2740) in 1999 and updated in 2008 (rfc5340). OSPFv3 was defined to only carry IPv6 addresses.Support of Address Families in OSPFv3 (rfc5838) uses the Instance ID to map address families. Added IPv4 support to OSPFv3.

Tb2380 retana transitioning from eigrp to ospf_final Tb2380 retana transitioning from eigrp to ospf_final Presentation Transcript

  • © Copyright 2012 Hewlett-Packard Development Company, L.P.The information contained herein is subject to change without notice.
  • Transitioning YourNetwork From EIGRP ToOSPFTB2380Alvaro RetanaJune 6, 2012© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • “When transitioning from one protocol to anotherthere are lot of things to consider. In this session,attendees will hear a technical review of what toconsider when transitioning from Enhanced InteriorGateway Routing Protocol (EIGRP) to OpenShortest Path First (OSPF). Attendees will gain ahigh-level overview of the protocols, network designconsiderations and more.”HP Discover 2012, Transitioning your network from EIGRP to OSPF© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • AgendaMotivationIntroductionEIGRP and OSPF overviewNetwork architecture considerationsTransition strategiesImplementation considerationsInformation hidingInter-area routing informationTraffic flowOSPF for IPv64 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Motivation: Why Migrate to a Standard ProtocolBy insisting on open standards in your network your business can realize multiplebenefitsLower capital expense• A vendor who knows you cannot easily incorporate a competitor’s products into your network is much less motivated at the bargaining tableBest-in-class solutions• Committing yourself to a single vendor using proprietary protocol sharply reduces your ability to seek out the best product on the market for each function of your networkLower risk• By diversifying your suppliers, you are less vulnerable to a single software malfunction affecting your entire network• Your network is also less at risk of product obsolescence, vendor buyouts, or business failuresInnovation• The most competitive enterprises see their network as a fundamental tool for business innovation• Agility, adaptation, and flexibility are the key qualities that keep your network ahead of your competitors5 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Debunking The Myth Of a Single VendorNetworkKey findings• No long term impact on OPEX• Lower TCO by at least 15-25% over five years• Multi vendor management tools ease the adoption of a second vendor• Lasting decrease in network complexity http://www.gartner.com/technology/media-products/reprints/hpprocurve/article7/article7.html6 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • IntroductionAll you need to know in 4 slides!© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • EIGRP and OSPF Overview Enhanced Interior Gateway Protocol Open Shortest Path First (OSPF) (EIGRP)Standardization • Never submitted to any standards body • Standardized by the IETF • OSPFv2 = rfc2328statusRouting • Diffusing Update Algorithm (DUAL) • Dijkstra Shortest Path First (SPF) • Developed at SRI International • Developed by Dr. Edsger Dijkstra in 1956algorithm • DUAL guarantees 100% loop free paths • SPF and strict inter-area propagation rules guarantee • Sub-second convergence can be achieved in the 100% loop free paths presence of feasible successors (no tuning • Sub-second convergence can be obtained through needed) tuning or the use of IP Fast RerouteSummarization • Auto-summarization at major network boundaries • Manual Route Summarization and Automatic Topology • Manual summarization at any point in the Aggregation at area bordersand hierarchy network • Supports two levels of hierarchy • Supports multiple levels of hierarchy • Carries intra-area topology information • No topology information carriedMetrics and load • Composite metric that can consider bandwidth, • Path cost is derived from the link bandwidth delay, load, reliability and MTU • Can load share over equal cost pathssharing • Can load share over both equal and unequal cost pathsIPv6 support • Supported in a separate instance • OSPFv3 (rfc5340) was developed for IPv6 support8 • Extensions exist to carry IPv4 in a separate instance © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Network Architecture Considerations Hierarchy structure & addressing scheme EIGRP allows for unlimited hierarchy levels, defined by the location of summarization points (manual or automatic) EIGRP − Route summarization is allowed at any router summarization points OSPF allows for two levels of strict hierarchy, defined by the placement of areas − Route summarization is allowed only at Area Border Routers (ABR) − The topology is automatically aggregated In general, the placement and type of an OSPF area should directly match the location and policies at the EIGRP summarization points9 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Transition StrategiesFlash transition / overlay1. Configure OSPF on the network with a high administrative distance2. Verify the OSPF routing information • The routes may not match if the EIGRP design used multiple summarization points3. Lower the OSPF administrative distance • The routing table should now contain only OSPF routes4. Remove EIGRP from the network EIGRP EIGRP EIGRP OSPF OSPF OSPF10 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Transition Strategies (2)Coexistence (redistribution)1. Configure mutual redistribution at the border between OSPF and EIGRP network regions • Coexistence may be temporary while different regions are transitioned EIGRP EIGRP EIGRP OSPF Redistribution OSPF Redistribution OSPF11 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • ImplementationConsiderationsThat was easy!!Are there other details to consider?© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Information HidingRoute summarization and topology aggregation are two commonmechanisms that result in the reduction of information propagatedthroughout the network• EIGRP doesn’t carry topology information• The topology knowledge at any router is limited to its directly connected neighbors• Route summarization can be configured at any point in the network• OSPF Area Border Routers (ABR) aggregate the topology and (can) summarize the routing information• Every router knows the full topology of the local area• Route summarization can only occur at an ABR or ASBR13 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPF as a Distance Vector ProtocolRouting information is propagated between areas only when it is beingusedOnly intra-area OSPF information in the routing table is converted to inter-area summaryLSAs and sent to the backbone (Area 0)Effect1. Before the transition, only Intra-area information will be present in the OSPF database2. During the transition, redistribution may be needed – especially when converting one area at a time14 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Intra-area Routing Considerations 100G EIGRP doesn’t have the concept of areas, 100G which result in no limitations on the traffic 100G flow patterns across the network OSPF always prefers intra-area routes, so 1G 100G the placement of area boundaries may affect the existing traffic flow15 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • EIGRP Traffic FlowMetric = BW + delay 100G 100G 100G 1G 100G16 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPF Traffic Flow100G Link in Area 1 Area 0 100G 100G 100G 1G 100G Area 117 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPF Traffic Flow (2)100G Link in Area 0 Area 0 100G 100G 100G 1G 100G Area 118 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPF Area PlacementPotential solutions1. Use a virtual link: place the 100G link in both areas2. Add more parallel 100G links, so that at least one is in each area3. Implement OSPF in a single-area configuration19 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPF for IPv6OSPFv2 = IPv4OSPFv3 = IPv6© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPF Evolution 1998 2008 2010 1989 1991 199921 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPFv3 and v2 Similarities • The same 5 packet types but some fields have been changed Packet type Description • Mechanisms for neighbor discovery and 1 Hello adjacency formation 2 Database description • Interface types 3 Link state request • P2P, P2MP, Broadcast, NBMA, Virtual 4 Link state update 5 Link state acknowledgment • LSA flooding and aging • DR, BDR election, area support, SPF • Nearly identical LSA types22 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPFv3 and OSPFv2 Differences• Changes made to OSPFv2 to accommodate increased address size of IPv6• OSPF now runs on per-link, not per-subnet• Removal of addressing semantics from OSPF packets and LSAs making it network protocol independent• New LSAs created to carry IPv6 addresses and prefixes• Addition of flooding scope (similar to RFC2370)• Explicit support for multiple instances per link• Use of IPv6 link-local addresses for protocol processing and providing next hop information during packet forwarding• Authentication method changes• Packet format & LSA’s header format changes• Handling of unknown LSA types 23 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPFv3 Flooding ScopeOSPFv2 had two flooding scopes• AS wide• Area wide LS age Options LS type LS age U S2 S1 LSA Function CodeOSPFv3 has three flooding scopes:• AS scope - LSA is flooded throughout the AS• Area scope - LSA is flooded only within an area• Link-local scope - LSA is flooded only on the local link24 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPFv3 Flooding ScopeU (unrecognized) bit is used to indicate to a router how to handle an LSA if itis unrecognized U-bit LSA handling 0 Treat this LSA as if it has link-local Scope 1 Store and flood this LSA as if type understoodS2 / S1 bit indicates the three flooding scopes S2 S1 Flooding scope 0 0 Link-local flooding scope 0 1 Area flooding scope 1 0 AS flooding scope 1 1 Reserved25 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • OSPFv3 LSA TypesList of LSAs in OSPFv3 LSA name LS type code Flooding scope LSA function code Router LSA 0x2001 Area scope 1 Network LSA 0x2002 Area scope 2 Inter-Area-Prefix-LSA 0x2003 Area scope 3 Inter-Area-Router-LSA 0x2004 Area scope 4 AS-External-LSA 0x4005 AS scope 5 Group-membership-LSA 0x2006 Area scope 6 Type-7-LSA 0x2007 Area scope 7 Link-LSA 0x0008 Link-local scope 8 Intra-Area-Prefix-LSA 0x2009 Area scope 926 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Dual-stack OSPF DeploymentMulti-instanceMultiple instances of OSPF on a given linkEnhances the ability to isolate the resources associated with both router and networkInstance specific prioritization for PDUs and routing calculationsConvergence considerationsIGPs will compete over processor cycles based on their relative tuning• If you configure the IPv4 and IPv6 IGPs the same way (aggressively tuned for fast convergence), naturally expect a doubling of their stand-alone operation convergence time• If the IPv6 IGP is operating under default settings, the convergence time for the optimally tuned IPv4 IGP is not significantly affected27 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Conclusions / SummaryBy insisting on open standards in your network your business can realize multiple benefitsIt is important to understand the differences in routing protocol operation and theimplications on the current network before starting a transition• Location of summarization points• Network hierarchy• Metrics, load sharing and traffic flow• Information propagation: topology and reachability information• Transition mechanisms (and which one is best for your network)• Protocol evolutionAlways the best protocol is the one which is right for your network28 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Tools to Help Our Clients• Read about the FlexNetwork Architecture• Learn about Virtual Application Networks• Discover Intelligent Management Center• View the HPN Portfolio Matrix Guide• Learn about networking services from HP Technical Services• Learn about networking career certifications from HP ExpertONE29 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Find out more Attend these sessions Visit these demos After the event • TB2375, Simplify large • HP Flex Network • Contact your sales rep scale secure WAN Architecture deployments, • Visit the HP Networking Wednesday @ 4pm • A holistic website at: approach to IPV6 http://www.hp.com/networking • TB3244, IPv6 Deployment: • Dynamic Virtual Understanding internal Private Network IPV6 protocols, (DVPN) Tuesday @ 4pm Your feedback is important to us. Please take a few minutes to complete the session survey.30 © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Q&A© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
  • Thank you© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.