Packet capture and protocol analysis applications enable you to investigate packet content as it flows through the network. The software decodes the protocol layers housed within a packet. Wireshark is an example of a popular open-source packet capture/protocol analysis application.
Bandwidth and throughput are characteristics of network data flow. Bandwidth is the theoretical amount of data that can be transmitted from one device to another in an amount of time. Bandwidth is typically measured in the number of bits per second. Throughput is the measurement of the actual number of bits per second that are being transmitted across the media. Throughput is always lower than bandwidth because of latency and delay. Online Internet speed test tools and the iPerf Windows tool enable measurement of throughput.
• Troubleshoot Connectivity Remotely—When assisting remote users, it may be more efficient to use remote desktop applications. These applications allow a technician to take control of a remote desktop to investigate issues and make configuration changes. Remote desktop applications can create security vulnerabilities and many organizations have desktop sharing disabled on computers. Microsoft Remote Desktop is included in all Pro versions of Windows. Apple Remote Desktop and TeamViewer are examples of other remote desktop software.
Telnet, SSH, and Remote Desktop Protocol (RDP) are protocols for remote access to systems. Telnet is an old virtual terminal application that is used to access the command line of a remote system. It uses TCP port 23. Telnet has no mechanism for encrypting transmitted data, and so should not be used. SSH, much like Telnet, enables virtual terminal sessions, but it includes encryption and should be used instead of Telnet. Virtual terminal clients such as PuTTY and Tera Term are available for connection to Telnet and SSH servers.
RDP was created by Microsoft. It also uses a client-server model in which the client accesses an operating system GUI on a remote computer. RDP software is available with Windows, OS X, Linux, and Unix via xrdp. For macOS, remote desktop functionality is provided by Virtual Network Computing (VNC) software.
Virtual private networks (VPNs) enable secure remote network access over unsecured networks like the Internet. A VPN uses dedicated secure connections that encrypt network traffic. Site-to-site VPNs connect entire remote facilities. Remote-access VPNs connect individual users to the corporate network. Remote-access VPN users connect to a corporate network VPN gateway using a software client such as Cisco AnyConnect. Microsoft Windows has its own VPN client.
Network management refers to the process of configuring, monitoring, and managing the performance of a network. Modern network management platforms provide advanced analytics, machine learning, and intelligent automation to continually optimize network performance. Network management systems typically use Simple Network Management Protocol (SNMP) and Remote Network Monitoring (RMON) to gather information. Network management systems can be deployed in cloud-based or on-premises models. Cloud-based deployments are good for distributed environments that are geographically dispersed. On-premises systems require a lot of computing power and storage but are good for situations where compliance with data-sovereignty regulations is required. Cisco Meraki is a leading cloud-based network management platform that provides powerful network management capabilities without consuming user bandwidth.
Network automation is the process of automating the configuring, managing, testing, deploying, and operating of physical and virtual devices within a network. Common labor-intensive tasks can be automated using scripts and network programmability. Python is a popular scripting language for network automation.
Lara did a great job creating a troubleshooting guide for help desk technicians. Sharing her help desk experience will help new technicians quickly become more effective. Was the information practical in this chapter? How are your diagnostic skills? Which troubleshooting approach would work best if a problem is related to cabling? Which troubleshooting approach would work best if the problem is related to an application?
Practice
The following activities provide practice with the topics introduced in this chapter.
Labs
Lab—Verify Address with a Subnet Calculator (37.4.9)
Lab—Install Wireshark (37.5.3)
Lab—Use Wireshark to View Network Traffic (37.5.4)
Packet Tracer Activities
Packet Tracer—Connect a Network Based on a Network Diagram (37.2.7)
Packet Tracer—Use CDP to Map a Network (37.2.12)
Packet Tracer—Troubleshooting Challenge—Document the Network (37.2.13)
Packet Tracer—Troubleshooting Challenge—Use Documentation to Solve Issues (37.5.6)