Chapter 3 of 6 · Cisco CCNP 350-401 ENCOR

Infrastructure

Layer 2 trunks, EtherChannel and Spanning Tree, Layer 3 routing with OSPF, EIGRP and BGP, and IP services.

  • 13topics
  • 1 h 11 minfast track
  • 7diagrams and exhibits
  • 30%of the exam
Start with 802.1Q Trunking and DTP Troubleshooting

Topics in this chapter

Take them in order, or jump to the one you need.

  1. 1802.1Q Trunking and DTP TroubleshootingTroubleshoot static and dynamic 802.1Q trunks: DTP modes, switchport commands, native VLAN and allowed VLAN problems, and the…5 min
  2. 2Static and Dynamic EtherChannel TroubleshootingTroubleshoot static and dynamic EtherChannels: LACP, PAgP and on modes, member consistency, show etherchannel flags, load…5 min
  3. 3Rapid PVST+ and MST Spanning TreeConfigure and verify Rapid PVST+ and MST on Catalyst switches: port roles and states, root bridge setup, MST regions and…Diagram6 min
  4. 4Spanning Tree Enhancements and GuardsConfigure and verify PortFast, BPDU guard, BPDU filter, root guard, loop guard and UDLD, and learn which spanning tree failure…Diagram6 min
  5. 5Comparing EIGRP and OSPF ConceptsCompare EIGRP and OSPF: advanced distance vector versus link state, metrics, load balancing, path selection, operation and the…Diagram6 min
  6. 6Configuring OSPFv2 and OSPFv3Configure OSPFv2 and OSPFv3 with multiple areas, network types, DR election, passive interfaces, ABR summaries and filters, and…6 min
  7. 7eBGP Neighbours and Best Path SelectionConfigure and verify eBGP between directly connected neighbours, read the neighbour states, advertise networks and apply the best…Diagram6 min
  8. 8Policy Based RoutingDescribe and configure policy based routing on IOS XE: route maps with match and set clauses, ip policy on an interface, next…5 min
  9. 9Interpreting NTP and PTP ConfigurationsRead and verify NTP configurations on Cisco IOS XE, covering stratum, servers, authentication and show commands, and see how PTP…5 min
  10. 10Configuring NAT and PATConfigure and verify static NAT, dynamic NAT and PAT on Cisco IOS XE, understand inside and outside address terms, and read the…5 min
  11. 11Configuring HSRP and VRRPConfigure and verify the first hop redundancy protocols HSRP and VRRP on IOS XE: virtual IP, priority, preempt, timers, tracking…Diagram5 min
  12. 12Multicast Basics, the RPF Check and PIM Sparse ModeUnderstand multicast addressing, the RPF check and PIM sparse mode with rendezvous points, shared and source trees, and verify it…Diagram6 min
  13. 13IGMP, SSM, Bidirectional PIM and MSDPLearn IGMP versions 2 and 3, source specific multicast, bidirectional PIM and MSDP between rendezvous points, with commands to…5 min

About this chapter

What this chapter covers

Infrastructure is the working core of an enterprise network: the switching, routing and services that move packets.

It has three parts that follow the outline.

The first is Layer 2, with trunks, EtherChannel and Spanning Tree. The second is Layer 3, with the OSPF, EIGRP and BGP routing protocols and policy based routing. The third is IP services, such as time, address translation, gateway redundancy and multicast.

The chapter follows the Infrastructure domain of the CCNP 350-401 ENCOR outline. It has four outline topics, and they are spread across thirteen pages because the subject is large.

How the topics fit together

The pages build from the lowest layer upward.

Trunks and EtherChannellinks between switchesloop free bySpanning Treeone active pathcarriesRoutingOSPF, EIGRP, BGPsupported byIP servicesNTP, NAT, FHRP, multicast
  • Trunks and EtherChannel carry many VLANs over bundled links.
  • Spanning Tree keeps the redundant Layer 2 links free of loops, and the guard features protect it.
  • OSPF, EIGRP and BGP exchange routes at Layer 3, and policy based routing overrides the result for chosen traffic.
  • NTP, NAT and gateway redundancy support the network that the earlier pages build.
  • Multicast delivers one stream to many receivers.
Note

Several pages end with troubleshooting steps, because this domain asks you to find faults as well as configure features.

How to use these pages

Each topic page has the same shape, so you can skim for what you need.

  • What it is: the idea in plain words.
  • How it works: the mechanism, with diagrams and example commands.
  • What to remember for the exam: the facts to memorise.
  • Common mistakes: the classic traps.
  • Check yourself: three questions to test your understanding.

This is a configuration heavy chapter, so use a lab or simulator. Type each example, then run the show commands and compare the output with the page. Pay attention to defaults, such as which side of a link must ask in a negotiation, because many questions test them.

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