Cisco CCNA (200-301): IP Connectivity and Routing
Table of Contents
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IP Connectivity is the heaviest domain on the Cisco CCNA (200-301) exam at 25%. This module covers how routers choose paths and how you configure static and OSPF routing. Spend extra lab time here, because this domain carries the most weight.
Routing connects separate networks. You learn to read the routing table, predict the forwarding decision, and build both static and dynamic routes.
The Routing Table
Every line in the routing table tells you how to reach a network.
| Field | Meaning |
|---|---|
| Protocol code | How the route was learned (C, S, O, D) |
| Prefix and mask | The destination network |
| Next hop | The address to forward toward |
| Administrative distance | Trust level of the source |
| Metric | Cost within a protocol |
| Gateway of last resort | The default route |
! View the IPv4 routing table
Router# show ip route
Forwarding Decisions
When several routes could match, the router applies clear rules in order:
- Longest prefix match wins first, since the most specific route is preferred.
- Administrative distance breaks ties between protocols.
- Metric breaks ties within the same protocol.
| Source | Administrative distance |
|---|---|
| Connected | 0 |
| Static | 1 |
| OSPF | 110 |
| RIP | 120 |
Static Routing
You configure static routes by hand for predictable paths. A default route sends all unknown traffic toward one next hop, and a floating static route backs up a dynamic route with a higher administrative distance.
! IPv4 static and default routes
Router(config)# ip route 10.2.2.0 255.255.255.0 192.168.1.2
Router(config)# ip route 0.0.0.0 0.0.0.0 192.168.1.1
! IPv6 static route
Router(config)# ipv6 route 2001:db8:2::/64 2001:db8:1::2
Single-Area OSPFv2
OSPFv2 is a link-state protocol that builds neighbor adjacencies and picks paths by cost. On broadcast networks, routers elect a DR and BDR to reduce flooding. The router ID identifies each router, and the highest loopback usually wins it.
! Enable OSPF process 1 in area 0
Router(config)# router ospf 1
Router(config-router)# router-id 1.1.1.1
Router(config-router)# network 192.168.1.0 0.0.0.255 area 0
Verify adjacencies with show ip ospf neighbor. A neighbor stuck in a non-full state usually means a mismatched subnet, area, or timers.
First Hop Redundancy
First hop redundancy protocols (FHRP) give hosts a default gateway that stays available. Two or more routers share one virtual IP, so if the active router fails, the standby takes over without changing client settings. HSRP is the common Cisco option.
Next Steps
Add network services in IP Services and protect your routers in Security Fundamentals . Review the switching base in Network Access and return to the Cisco CCNA Course .
