CCNA certification prep: Network Access

Introduction

Network access topics make up a sizable part of the 200-301 CCNA exam. This article describes what is and is not covered by network access and what you need to know to be well-prepared for the exam.

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What percentage of the exam focuses on network access?

Your CCNA exam is 20% network access questions, which makes it an important topic. Network access technologies are also relevant to entry-level networking and IT roles.

What topics are covered in this section of the exam?

The CCNA exam includes the following topics under the umbrella of network access:

1. Configure and verify VLANs
2. Configure and verify inter-switch connectivity
3. Configure and verify Cisco Discovery Protocol and LLDP
4. Configure and verify EtherChannel (LACP)
5. Rapid PVST+ Spanning Tree Protocol
6. Cisco Wireless Architectures and AP modes
7. WLAN components
8. AP and WLC management access connections

To know what's covered by each of these topics and the level of understanding and skills you need to have in each area, read on.

High-level overview of network access topics

The CCNA certification covers wired and wireless network access technologies. We’ll be exploring those next.

How to configure and verify VLANs

You can create two (or more) broadcast domains with a single switch by creating two (or more) VLANs, or virtual LANs. You assign some interfaces of the switch to the first VLAN and assign the rest to the second VLAN. The switch knows which interfaces belong to which VLAN.

Learn how to configure and verify VLANs and know the available configuration options. To create a VLAN, use the vlan vlan-id command in global configuration mode. To assign an interface to a VLAN, use the switchport access vlan vlan-id command in interface configuration mode. You can verify your configuration by using the show vlan brief command.

How to configure and verify inter-switch connectivity

In multi-switch LANs, a VLAN spans multiple switches. You create inter-switch links that carry traffic that belongs to multiple VLANs. This is known as VLAN trunking, which is enabled by a process called VLAN tagging.

You should be able to configure and verify inter-switch trunks built with IEEE 802.1Q or ISL (Inter-Switch Link) trunking protocols. The CCNA exam focuses more on 802.1Q than ISL. You can create a functional trunk between two Cisco switches by using only the switchport mode trunk command in the interface configuration mode. To display information about all trunks on a switch, use the show interfaces trunk command in user EXEC mode.

How to configure and verify Cisco Discovery Protocol and LLDP

CDP (Cisco Discovery Protocol) is a Cisco-proprietary protocol that is used to learn details about directly connected devices. Think of LLDP (Link Layer Discovery Protocol) as the vendor-neutral counterpart of CDP. 

You need to know how to enable and disable CDP/LLDP globally and on individual interfaces. You should be able to use the relevant show commands to verify configuration and glean information about neighbors.

How to configure and verify EtherChannel (LACP)

EtherChannels are used to bundle multiple links between switches to make efficient use of available bandwidth and reduce the number of times STP must converge. EtherChannels can be Layer 2 or Layer 3 and can be configured statically or dynamically using the LACP (Link Aggregation Control Protocol) or PAgP (Port Aggregation Protocol) protocols.

You need to know the configuration and verification of Layer 2 and Layer 3 EtherChannels. You also have to be familiar with common configuration issues that occur with EtherChannels.

Rapid PVST+ Spanning Tree Protocol

STP (Spanning Tree Protocol) allows you to reap the benefits of installing redundant inter-switch links while avoiding associated problems. STP evolved into RSTP (Rapid Spanning Tree Protocol). Modern Cisco switches default to using RSTP.

The STP/RSTP operation is complex but it does not require a lot of configuration. We recommend that you learn core RSTP concepts and work with RSTP configuration and verification to more fully understand those concepts.

Cisco wireless architectures and AP modes

Wireless access networks bring mobility and convenience and allow users to stay connected to the network as they move around. There are different approaches or architectures for networking APs (access points) together to form WLANs (wireless LANs).

The wireless architectures covered are: autonomous AP architecture, split-MAC architectures and cloud-based AP architecture. The autonomous AP architecture consists of one or more fully functional, standalone, individually managed APs. In split-MAC architectures, the management function is removed from the AP and pushed to a central device known as WLC (wireless LAN controller). The AP must still interact with wireless clients at the MAC (Media Access Control) layer. The cloud-based AP architecture is a special case of split-MAC architectures where the central management function is moved to the internet cloud rather than a WLC.

You should be able to compare and contrast the three wireless architectures. You should also understand how data moves through the network, how APs are managed and how deployment and troubleshooting is performed for each architecture.

How to configure WLAN components

Beyond knowing wireless fundamentals and architectures, you should be able to build a working wireless LAN with APs and a WLC.

AP and WLC management access (Telnet, SSH, console and so on)

There are multiple ways to access APs and WLC for configuration and troubleshooting.

Console

To configure a Cisco AP or WLC, you can connect a serial console cable from your PC to the console port on the AP. Once connected, you get a CLI (command-line interface) that can be used to perform initial configuration.

Telnet

Once you configure an IP address and gateway on the AP or WLC via console, you can use Telnet to connect to its CLI over the wired network.

SSH

As the more secure alternative to Telnet, you can use SSH to connect to the AP or WLC CLI over the wired network.

Others

You can use a web browser to access the management GUI (graphical user interface) of a standalone AP via HTTP or HTTPS. You also use a web browser to access the management GUI of a WLC and manage access points linked to the WLC from there.

Where should I focus my time studying?

Network access encompasses both wired and wireless network access products and technologies. Wired network access includes concepts, configuration and verification for VLANs, trunking, STP/RSTP, CDP/LLDP and EtherChannels. You should have a deep understanding of these technologies and should also be able to configure and troubleshoot them on Cisco devices. 

The wireless network access is the smaller yet important component. You should have a good understanding of wireless network architectures and should be able to access and configure APs and WLCs to build functional wireless LANs.

Conclusion

Network access is an important component of the 200-301 CCNA exam. It includes both wired and wireless network access technologies. Wired network access concepts, configuration and verification are covered in some detail. For the wireless network access part, a broader understanding of wireless architectures and traffic flows is expected. You should be able to perform basic management of WLAN components via CLI and GUI.

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Sources

1. CCNA Certification and Training, Cisco
2. Wendell Odom, "CCNA 200-301 Official Cert Guide, Volume 1," Cisco Press, 2019
3. Wendell Odom, "CCNA 200-301 Official Cert Guide, Volume 2," Cisco Press, 2019