CCNP Routing

My notes from studying for the retired Cisco CCNP ROUTE exam, covering IP routing, OSPF, EIGRP, BGP, MPLS L3VPN, GRE, IPsec, and DMVPN.

I wrote these notes while studying for the Cisco CCNP ROUTE exam between December 2017 and January 2018, and I originally published them on my GitHub. They follow the exam blueprint of that era, working from IP routing fundamentals through OSPF, EIGRP, and BGP into MPLS L3VPN and VPN technologies such as GRE, IPsec, and DMVPN.

Archived Notes

Cisco retired the CCNP Routing and Switching track in February 2020 and replaced it with CCNP Enterprise. I have kept these pages close to how I first wrote them, with only light formatting cleanup. Each page carries the date I wrote it, and the command output comes from the IOS versions I was running at the time. The concepts (OSPF, EIGRP, BGP, MPLS) remain as relevant as ever.

Topics

IP Routing Overview

Overview of IP routing, the IPv4 and IPv6 packet headers, IPv6 address types and assignment methods, and IPv4 to IPv6 interoperability.

Transport Layer

Notes on transport layer services, the TCP and UDP headers, flow and congestion control, and real time media delivery with RTP and RTCP.

Cisco IOS IP Service-Level Agreement (IP SLA)

How Cisco IOS IP SLA measures network performance and pairs with tracked static routes to fail over based on end to end reachability.

Policy-Based Routing (PBR)

How policy based routing overrides destination based forwarding on Cisco routers, with a route map example that steers traffic by source IP address.

Configuring WAN Technologies

Notes on PPP over serial WAN links, PAP and CHAP authentication with a worked two router example, and the PPPoE discovery stages.

Open Shortest Path First (OSPF)

Covers OSPF LSA types, areas and area types, DR and BDR election, network and packet types, neighbor states, and authentication.

Virtual Link Configuration

Step by step OSPF virtual link configuration in a five router lab, verifying routing tables and DoNotAge LSAs, plus link authentication.

OSPF Route Summarization

Shows why OSPF allows summarization only between areas and how to configure area range on ABRs, with routing tables before and after.

Redistribution into OSPF

Redistribute connected and EIGRP routes into OSPF, compare E1 and E2 external routes, set default metrics, and verify with LSA and route table output.

IP Prefix List

Use IP prefix lists with ge and le matching and route maps to filter routes and change OSPF external route types in a worked redistribution example.

Injecting Default Routes

Inject a default route into OSPF with default-information originate, compare the always keyword, and inspect the resulting Type 5 external LSAs.

OSPF Area Types

Compare standard, stub, totally stubby, NSSA, and totally NSSA areas and observe how each area type changes the LSAs in the OSPF database.

Type 3 LSA Filtering

Filter OSPF Type 3 LSAs between areas with an area filter-list and remove routes from the routing table with an inbound distribute-list.

OSPFv3

Learn how OSPFv3 differs from OSPFv2, including the Type 8 and Type 9 LSAs, and configure the address family approach for IPv4 and IPv6 routing.

Enhanced Interior Gateway Routing Protocol (EIGRP)

Cover EIGRP fundamentals such as DUAL, feasible successors, packet types, stub routers, the metric formula, and named versus traditional configuration.

EIGRP Named Configuration Approach Example

Configure EIGRP for IPv4 and IPv6 with the named approach, compare it with a traditional configuration, and verify neighbors, topology, and authentication.

EIGRP Stub Configuration

Lab walkthrough of EIGRP stub routing showing how the stub connected summary and receive-only options change what routes a router advertises.

EIGRP Route Summarization

Notes on EIGRP auto and manual summarization, configuring a per-interface summary address, and verifying the summary route and its Null0 entry.

Redistribution into EIGRP

Lab on mutual redistribution between OSPF, EIGRP, and RIP, the suboptimal routing it can cause, and route tags that prevent routing domain loops.

Border Gateway Protocol (BGP)

Introduction to BGP covering path vector routing, eBGP and iBGP peering, route injection, next-hop self, and options such as route reflectors.

BGP Scenario

Full lab scenario building eBGP and iBGP peerings across three autonomous systems, injecting routes, and verifying neighbor and BGP table state.

BGP Route Filtering

Notes on filtering BGP updates per neighbor with prefix lists and route maps so that a customer AS does not become a transit AS.

BGP Cisco-proprietary Weight Settings

Lab on the Cisco BGP weight setting, applied per prefix with a route map and per neighbor, to influence one router’s choice of outbound path.

BGP Path Attributes

Overview of the BGP best path selection order and a lab that uses local preference to steer an autonomous system toward a preferred exit point.

BGP Path Attributes - AS Path

Influence which path BGP prefers by prepending entries to the AS path with a route map, shown with Cisco configuration and verification.

BGP Path Attributes - Multi-Exit Discriminator (MED)

How the Multi-Exit Discriminator attribute lets a dual-homed enterprise tell its ISP which inbound link to prefer, with route map configuration.

BGP Support for IPv6 (Multiprotocol BGP)

How multiprotocol extensions let BGP carry IPv6 and other address families over one TCP session, with IPv4 and IPv6 configuration examples.

Multiprotocol Label Switching (MPLS)

Introduces MPLS label switching, LSR roles, LDP label distribution, the FIB, LIB, and LFIB tables, and penultimate hop popping.

Configuring a Label Switched Network

Step by step MPLS core configuration with LDP on Cisco routers, then verification of LDP neighbors, label bindings, and the LFIB.

MPLS L3VPN

Why MPLS L3VPN uses VRFs, route distinguishers, and route targets to keep customer routes separate, plus how packets flow across the provider core.

Configuring MPLS L3VPN

Full MPLS L3VPN configuration on Cisco routers, covering VRFs, MP-iBGP for VPNv4, PE-CE routing with BGP and EIGRP, and label analysis.

Generic Routing Encapsulation (GRE)

Notes on GRE tunneling covering the header overhead, common use cases such as GRE over IPsec and IPv6 transport, and a working two router lab.

Site-to-site IPsec VPN

Covers IPsec building blocks, IKE phase 1 and phase 2 negotiation, and site-to-site VPN configuration on Cisco IOS with crypto maps and VTI.

Dynamic Multipoint VPN (DMVPN)

Introduces DMVPN components such as mGRE, NHRP, and IPsec, how spokes register with the hub, and how phases 1, 2, and 3 differ in spoke traffic.

DMVPN Phase 1

Builds a DMVPN Phase 1 lab with mGRE and NHRP on the hub, then runs RIP, EIGRP, OSPF network types, and several BGP designs over the tunnel.

DMVPN Phase 2

Converts branches to multipoint GRE for DMVPN Phase 2 and shows how RIP, EIGRP, OSPF, and BGP handle next hops for spoke to spoke traffic.

DMVPN Phase 3

Migrates the lab to DMVPN Phase 3 with NHRP redirect and shortcut so spokes build tunnels on demand, tested with RIP, EIGRP, OSPF, and iBGP.

DMVPN Over IPsec

Protects a DMVPN Phase 3 network with IPsec using an ISAKMP policy, a transport mode transform set, and a tunnel protection profile.