CCNA Topologies: The Basics
Before buying your first Cisco lab gear, it can be helpful to think about the topologies of gear you would use when practicing for the exam. Then, you can let the topologies drive the number of routers and switches you need to buy or borrow. This page examines several alternative topologies that can be useful for CCNA preparation.
Some of the sample topologies shown here focus on routers, and some focus on switches. The topologies can of course be combined, but for the sake of discussion, the topologies listed on this page keep either a router or switch focus. Also, all topologies assume at that you have one PC that can be connected via Ethernet and to the device consoles for testing and configuration.
Router WAN Topologies: Progression of Benefits
Solo Router (CLI Syntax Practice)
Benefits:
- Practice real Cisco CLI syntax for all features
- DHCP
- IPv4 and IPv6
- SSH
Router Serial Pair
Adds These Benefits over Single Router:
- RIP, EIGRP, and OSPF
- Static Routes
- NAT/PAT
- Basic Layer 3 redundancy
- DHCP Relay
- HDLC, PPP
- ACLs
Router Serial Triangle
Adds These Benefits over Router Pair:
- Much Better routing protocol redundancy
- Supports more OSPF areas
- Allows better experiments with automatic summarization
Router Serial Square
Adds These Benefits over Router Triangle:
- Even better routing protocol redundancy
- Easier support for 3 Frame Relay DTEs
Router LAN Topologies: Progression of Benefits
Solo Router with Two LAN Interfaces
Benefits:
- Practice real Cisco CLI syntax for all features
- DHCP
- IPv4 and IPv6
- SSH
- Connected Routes
Router LAN Square
Adds These Benefits over Single Router:
- Demonstrates OSPF DR/BDR/DROther much better than other topologies
- Best design (so far) for testing routing protocol neighborship issues
Switch LAN Topologies: Progression of Benefits
Solo Switch (CLI Syntax Practice)
Benefits:
- Switch admin
- VLANs
- VTP
- 802.1Q trunking from switch to router
- VLAN configuration
- Voice VLANs
- Port Security
Switch Pair
Adds These Benefits over Single Switch:
- Allows configuration of all CCNA Spanning Tree features
- Etherchannel
- Supports meaningful VTP experiments
- Switch-to-switch trunking (802.1Q)
Switch Triangle
Adds These Benefits over Switch Pair:
- Uses the triangle design suggested by Cisco LAN design documents
- Much more interesting Spanning Tree Topology; harder to predict
- Can run even more meaningful VTP experiments (eg 2 servers, 1 client)