August 11, 2019 » NetworkUstad

Network Baseline – Everything to know

August 11, 2019

Do you know your standard network throughput volume and the types of traffic used in your network? You should require a network baseline if you don’t know the answers to the above questions. The network baseline is one of the most valuable tools for monitoring and troubleshooting network performance.

For an influential network, a baseline performance record is required over time. Measuring performance at varying times and loads will help in creating a better image of overall network performance

How to baseline a network

To baseline a network, you need to monitor the traffic for a long time because a more comprehensive time presents a more realistic picture of a traffic pattern. We can use the network baseline as listed below:

Evaluate network management policies agreement.
Understand network patterns and traffic trends.
Speed up troubleshooting network problems.
Understand network resource allocation.
Provide network up-gradation history statistics.
Provide data for decision-making as well as for network and security management.

Network administrators need the software Colasoft nChronos and Capsa to baseline a network. Both software listens to packet data from wires and generates various reports on the network. Further, the network administrator can copy, paste, and save the results from an executed ping, trace, and other related commands into a text file with time and date.

Then, the network administrator can use these text files to compare with other results, error messages, and response times from host to host. If response times massively increase, there may be a latency issue to address. The figures below illustrate the result of the ping command for the same IP address with different timings and the comparison of both.

A screenshot of a Command Prompt window showing the results of a ping test to the IP address 192.168.1.2, with successful replies and no packet loss. — Command Prompt Ping Test Results

A screenshot of a Command Prompt window showing the results of two ping tests to the IP address 192.168.1.2, with varying response times and no packet loss. — Ping Command Results on Command-Line Interface

The output resulting from network commands can give data to the network baseline. Commercial networks should have widespread baselines. Professional-grade software tools are also available for storing and maintaining baseline information.

Interpreting Cisco Devices Ping Results

Asad Ijaz / CCNA /

August 11, 2019

The ping is a very helpful utility to test and troubleshoot network devices connectivity. It uses the Internet Control Message Protocol (ICMP). The ping results indicate the source of the problem. It is also a first step in troubleshooting a network failure. So, understanding ping results is very important for the student of networking.

Cisco IOS Ping Indicators

There are several ping results and indicators in IOS for ICMP echo request that was sent. The common indicators for ICMP echo are the following:

! – The mark of exclamation indicates that the ping completed successfully and verifies Layer 3 connectivity along the network path. As shown in Figure below, Karak Router Successfully ping Peshawar router, which IP address is 172.16.0.1

“.” The period indicates that there is some problem in connectivity somewhere along the network path. It also indicates that a router along the network path does not configure a route to the destination. If the ping is not allowed in the device it should also give a reply with “.” Indicator. The first echo request timed out is common in the network If the arp process is required.

The figure below shows the ping result from Karak router to laptop 3, where “Karak router” has no route to the network 192.168.1.0/24, so its reply with request timed out “.” Indicators.

U – This indicator shows that a router along the network path responded with an ICMP unreachable message because the router did not have a route configure to the destination address. If the destination blocked the ping request it will also reply with this mark.

Testing the Loopback

To verify the internal IP configuration and protocol stack from the network layer to the physical layer the administrator can also use the ping command instead of putting a signal on the media. The Loopback IP addresses are 127.0.0.1 for IPv4 and ::1 for IPv6. We can examine the ping results for loop back interfaces similar to other interfaces.

Extended Ping

The extended ping is one of the best commands offers by Cisco IOS. This is also the extended mode of the ping command. To execute and get extended ping results only enter ping command without destination address in privileged EXEC mode.

As shown in the figure below, a series of different prompts are then presented asking different parameters. Pressing Enter without writing something accepts the indicated default values.

The figure below illustrates how to force the source address for a ping to be 192.168.1.1(Router Peshawar); the source address far a standard ping would be 172.16.0.2. The network administrator can verify from Peshawar Router that the Karak Router has a route to 192.168.1.0/24 network.

Cisco Router File System – Exclusive Details

Mudassir K / CCNA /

August 11, 2019

The Cisco IOS File System (IFS) has different directories, depending on the device. The IFS also allows the creation of subdirectories in flash memory or on a disk. The figure below displays the output of the show file system command, which lists all of the available file systems on the router.

The command gives helpful information such as the information about available and free memory, the file types, and its permissions. Permissions contain read-only (wr), write-only (ro), and read-and-write (rw). The asterisk against the Flash file system means Flash is the current default file system. The pound symbol (#) appended to the flash indicates that bootable IOS is in a flash.

The Flash File System

The figure below displays the output of the dir command. Since Flash is the default file system, the dir command lists the contents of Flash.

The NVRAM File System

To view and list the contents of NVRAM, the command will be given as dir NVRAM: in user exec mode. as shown in the Figure below.

Switch File Systems

The show file systems command also shows the file systems on a Catalyst switch, which are the same as on a Cisco router, as shown in the figure.

Backup and Restoring using Text files

Backup

Using Tera Term, we can also back up the Configuration file and restore the configuration from the text file when needed. The steps for backup and restoring using Tera Term is the following:-

On the File menu of Tera Term, click Log.
Then select the location where you want to save the file. Now Tera Term will start capturing.
Once the capture has been started, execute the show running-config or show startup-config command at the privileged EXEC prompt. The displayed text in the Tera Terminal will be directed to the chosen file.
After completing the capture, select Close in the Tera Term: Log window.
View the file at the chosen location to verify that it was not corrupted.

Restoring

When configuration is copied from a text file and pasted into a terminal window, the Inter Operating System executes each line of the text file as a command. So, the captured file will require editing to ensure that encrypted passwords are in plain text and that there is no non-command text.

Furthermore, the device must be set to the global configuration mode to receive the commands from the text file pasted into the terminal window. The following are the steps to restore the configuration using Tera Term.

On the File menu of Tera Term, click Send File.
Locate the configuration text file to be copied into the device and click Open.
Tera Term will paste the file into the device, and the text will be applied as a command.

Backup and Restoring Configurations with TFTP

Backup

Startup configuration or running configuration files can be stored on a TFTP (Trivial File Transfer Protocol) server and restored in the event of a problem. The configuration file should also be included in the network documentation.

To save the running configuration or the startup configuration file to a TFTP (Trivial File Transfer Protocol) server, use the copy running-config tftp or copy startup-config tftp command. Following are the steps to back up the running configuration to a TFTP server:

Enter the copy running-config tftp command in user exec mode and then enter the hostname or IP address where the configuration file will be stored.
Enter the name to assign to the configuration file.
Press Enter to confirm every choice.

The figure below illustrates the backup process to TFTP.

Restoring

To restore the running configuration or the startup configuration from a TFTP (Trivial File Transfer Protocol) server, use copy tftp running-config or copy tftp startup-config command. Following are the steps to restore the running configuration from a TFTP server:

Enter the copy tftp running-config command in user exec mode then enter the hostname or IP address where the configuration file is stored.
Enter the name to assign to the configuration file.
Press Enter to confirm each choice.

The Figure below illustrates the restore process from the TFTP server.

Backing Up and Restoring Using a USB

Backup

Before backing up to a USB port, it is important to verify that the USB drive is there and confirm the name of the drive using the show file systems command in the user exec mode. If the USB drive is there, use the copy run usbflash0:/ command to copy the configuration file to the USB flash drive. Be sure to use the name of the flash drive exactly, as indicated in the file system.

The slash indicates the root directory of the USB flash drive. Then the IOS will prompt for the filename. If the file already copied and exists on the USB flash drive, the router will then prompt to overwrite. We can see files and directories in the USB using the dir command.

Restore

To copy the file back, use the command copy usbflash0:/Router-Config running-config to restore a running configuration where Router-Config is the backup file name in the USB.

Small Network Growth

Asad Ijaz / CCNA /

August 11, 2019

Network Growth is a natural process, like other businesses; it must grow with time. Many larger companies start as small companies. The world-leading Microsoft company began with two people. A strategic plan will help you develop your company. Ideally, the network administrator has much time to make intelligent decisions about network growth in sequence with the company’s development. The following elements are essential for deciding when scaling a small network into an extensive one.

Network documentation – diagram of the physical and logical topology

Device inventory – The list of devices included in the network

Budget – itemized IT budget, including fiscal year equipment purchasing budget

Traffic analysis – protocols, applications, services, and their respective traffic requirements, e.g. bandwidth and disk/storage capacity, should be documented and planned.

Network segmentation requirements. Based on performance, Security, Management, and availability requirements.

Protocol Analysis

When network growth is in progress, it is important to understand the type of traffic that will be crossing the network, including current traffic flow. If the types of traffic are not known, a protocol analyzer can help recognize the traffic and its source.

During peak hours, try to capture the network traffic to determine the traffic types. Also, perform capture on different network segments to better understand. The figure below illustrates the network analyzer for different segments.

The protocol analyzer analyses the bases of its source and destination and the type of traffic sent to the destination. The analysis can be used to decide how to manage the traffic efficiently when relocating a server.

Employee Network Utilization

During Network Growth, a network administrator must understand how network usage will change. In addition to understanding changing traffic trends, a network administrator must know how network use changes.

The small network administrator can get “snapshots” of employee applications used for an essential part of the employee workforce occasionally. These snapshots may contain information about:

Operating System and its version
Both Network and Non-Network work application
CPU, Drive and RAM Utilization

Common Applications

Asad Ijaz / CCNA /

August 11, 2019

The network is not very useful without applications. Applications are software programs that communicate over the network or processes that give access to the network. There are two types of applications: network applications and application layer services.

Network Applications

Network applications communicate over the network. Some end-user applications apply application layer protocols and can communicate directly with the lower layers of the protocol stack. For example, Email clients are network applications.

Application Layer Services

Network print spooling and file transfer over the network are requisite application layer services for using network resources. These services are the software programs that interface with the network and organize the data for transfer. Several types of data, e.g., text, graphics, audio, and video, are wanted different network services to ensure the data is ready for processing.

Each application or network service uses protocols describing the data standards and formats. There is no way to format data without standard network protocols. Before understanding the role of network services, understanding protocols is very important. In the Windows operating system, we can view the current application, services, and running process, as shown in the above figure. The following are the standard protocols used in networking:-

DNS

DNS was created to convert a numeric address into a simple, recognizable name. DNS stands for Domain Name System (Service or Server).

Telnet

Telnet is a service that allows network administrators to log in to a host remotely and control it just like they are working locally.

Email Server

SMTP, POP3, or IMAP send email messages from clients to servers over the Internet.

DHCP Server

DHCP is the service that automatically assigns the IP address, subnet mask, default gateway, and other information to clients.

Web Server

Web servers transfer information and data between web clients and web servers. The majority of websites are accessed through HTTP (Hypertext Transfer Protocol)

FTP Server

The FTP service allows the download and upload of files between a client and a server.

Voice and Video Applications

Streaming media is very important for businesses to communicate with customers and business partners. The network administrators must care about the equipment configuration and installation and ensure it meets the requirements of real-time applications. The administrator also determines whether the present switches and cabling can support the traffic that will be added shortly.

VoIP

VOIP stands for Voice Over Internet Protocol. In standard terms, VOIP is a call service over the Internet.
VOIP requires a quality Internet connection to get phone service through an Internet connection instead of the local phone company. We can also use VoIP with traditional phone service because VOIP service providers typically offer lower call rates than traditional phone services.

We can also use a traditional phone set with an ATA (analogue telephone adapter), which converts the analogue signal into digital IP packets and vice versa. The administrator can attach the device between a traditional analogue phone and the Ethernet switch. VoIP is much less expensive than an integrated IP telephony solution, but the quality does not meet the same standards.

IP Telephony

In IP telephony, the ATA adapter is no longer required because the IP phone itself performs the voice-to-IP conversion. IP phones also use a separate server for call control and signaling.

Real-time Applications

A real-time application is a software program that works within a time frame the user senses as current. This software uses the Real-Time Transport Protocol (RTP) and Real-Time Transport Control Protocol (RTCP).

The QoS mechanism controls the latency of less than a defined value, usually measured in seconds. For example, video conferencing applications, online gaming, and video chatting are Real-time applications.