Understanding Wireless Heat Maps: Key to Optimal Network Planning

 Wireless Heat Map

A wireless heat map is a visual tool used to represent a wireless network's signal strength and coverage within a specific area. Here are the key aspects:

What It Shows

• Signal Strength: Heat maps use color gradients to show areas with strong and weak signals. Typically, warmer colors (red and orange) indicate stronger signals, while more excellent colors (blue and green) indicate weaker signals.
• Coverage: They help visualize the coverage area of wireless access points, showing where the signal is strong and where it might be weak or non-existent.
• Interference and Noise: Some heat maps also display areas with high interference or noise, which can affect the quality of the wireless connection.

How It's Used

• Network Planning: Helps strategically place access points to ensure optimal coverage and performance.
• Troubleshooting: Identifies dead zones and areas with poor signal strength, helping to diagnose and fix connectivity issues.
• Optimization: Optimizes the network by adjusting access point placement and settings to improve overall performance.

Creating a Heat Map

• Software Tools: Specialized software like NetSpot, Ekahau, and AirMagnet Survey are commonly used to create wireless heat maps. These tools collect data on signal strength and other metrics and visually represent the network.

Understanding RSSI: What it Means for Your Wi-Fi Signal Strength

 RSSI

RSSI stands for Received Signal Strength Indicator. It measures the wireless signal strength and Wi-Fi signal quality and indicates how well a device can receive a signal from a router or access point.

RSSI is useful for determining whether a device has enough signal to maintain an excellent wireless connection. It's usually not visible to the receiving device's user, but IEEE 802.11 devices often make the measurement available.

Factors that can affect RSSI include:

• Obstructions between the router and the device, such as walls or doors
• Signal interference from other electronic devices
• Distance between the router and the device
• Multiple devices streaming to the router
• An outdated router

RSSI is not the same as transmitting power from a router or access point because it pulls power from the client device's Wi-Fi card.

Cable Certifiers vs. Cable Testers: Understanding the Differences

 Cable Tester vs Cable Certifier

The terms “cable certifier” and “cable tester” often get used interchangeably, but they refer to different tools with distinct purposes in network cabling.

Cable Tester

A cable tester is a general term that includes various tools used to check the basic functionality of network cables. These tools can be divided into two main categories:

Verification Testers:

• Purpose: Check basic connectivity and wiring.
• Functions: Verify if the cable is connected correctly, check for continuity, and identify wiring issues like crossed wires.
• Use Case: Ideal for quick troubleshooting and ensuring that cables are correctly connected.

Qualification Testers:

• Purpose: Determine if the cable can support specific network speeds and technologies.
• Functions: Test if the cable can handle data rates like 100BASE-TX, Gigabit Ethernet, or VoIP.
• Use Case: Useful for assessing whether existing cabling can support new network requirements.

Cable Certifier

A cable certifier is a more advanced tool used primarily by professional installers and network technicians to ensure that cabling meets industry standards.

• Purpose: Certify that the cable installation complies with specific standards (e.g., TIA/EIA or ISO).
• Functions: Perform detailed tests such as insertion loss, return loss, near-end crosstalk (NEXT), and more. Based on these standards, it provides a “Pass” or “Fail” result.
• Use Case: Required for installations where compliance with standards is necessary, often for warranty purposes or to meet contractual obligations.

Key Differences

• Detail and Accuracy: Certifiers provide more detailed and accurate measurements than testers.
• Standards Compliance: Certifiers are necessary for proving compliance with industry standards, while testers are generally used for basic troubleshooting and verification.
• Cost: Certifiers are typically more expensive due to their advanced capabilities and the detailed reports they generate.

In summary, a cable certifier is the way to go if you must ensure that your cabling meets specific standards and can support high-performance networks. A cable tester will suffice for basic troubleshooting and verifying connections.

Mastering Cable Tracing: The Role of Toner and Probe Devices

 Toner and Probe

A toner and probe are handheld devices that trace and identify electrical systems, telecommunications, and networking cables. The two devices are:

Tone generator

A portable device that emits a signal or audible tone onto a specific wire or cable

Probe

A portable device that detects the signal or tone produced by the tone generator

A toner and probe is used to:

• Trace the cable from the wall plate to the port on the patch panel.
• Trace and identify wires or cables in a bundle or group without damaging cable insulation

A toner and probe effectively trace electrical cables hidden in building walls, floors, and ceilings. The tester sends an electrical pulse that bounces back when it reaches a cable. The device then picks up these pulses and displays them on its screen.

Applications

• Telecommunications: Identifying and tracing individual wires within a cable.
• Networking: Tracing Ethernet cables in a LAN setup.
• Cable TV and Audio Systems: Identifying and tracing coaxial cables.

Understanding Syslog Logging Levels: From Emergency to Debug

 Syslog Logging Levels

Syslog logging levels, also known as severity levels, indicate the importance or urgency of log messages. They range from 0 to 7, with 0 being the most severe and 7 being the most minor severe:

0: Emergency, the system is unusable

1: Alert, action must be taken immediately

2: Critical, critical conditions

3: Error (error): error conditions

4: Warning (warn): warning conditions

5: Notice (notice): normal but significant conditions

6: Informational (info): informational messages

7: Debug (debug): messages helpful for debugging

Log levels help prioritize responses and actions. For example, alert and emergency messages are used when something wrong occurs, while critical, error, and warning messages are used for important events.

Syslog is a centralized logging system that collects messages from various devices and applications. It's used for monitoring, troubleshooting, and security analysis.

Regular logging is set to 0 through 4 and is forwarded; events for levels 5 through 7 are not forwarded. 

Understanding Syslog Servers: Key Benefits and Components

 Syslog Server

A syslog server is a device or software that receives, stores, and manages log messages from other devices on a network. Syslog servers are also known as syslog collectors or receivers.

Syslog servers are helpful for:

• Centralized log management: Syslog servers allow administrators to manage logs from multiple devices in one place, making it easier to search, filter, and view log messages.
• Identifying network issues: Syslog servers can help determine the root cause.
• Regulatory compliance: Syslog servers can help demonstrate compliance with regulatory frameworks that require log retention.

Syslog servers typically include the following components:

• Syslog listener: Gathers event data and allows the collector to start receiving messages
• Database: Stores log messages for long-term retention and analysis
• Tools and interfaces: Provides tools for log analysis, filtering, and reporting

Syslog servers can be physical servers, virtual machines, or software. They listen for incoming syslog messages on a designated port, typically 514 for UDP or 601 for TCP.

Understanding SNMP Community Strings: A Key to Network Security

 SNMP Community String

An SNMP community string is a password that allows devices to communicate with each other and access a device's statistics:

• Purpose: A security password that controls access to a device's statistics
• How it works: A user sends the community string along with a GET request to access a device's statistics
• Types: There are three types of community strings: read-only, read-write, and trap
• Use: SNMP community strings are used by devices that support SNMPv1 and SNMPv2c
• Default: Most devices have a default community string, often set to "public."
• Importance: It's essential to change the default community string to maintain device and network security

SNMPv3 provides network security. All three provide device communication.

During device setup, network managers typically change the default community string to a customized value. If the user has read/write/all access authority, the community string can be set using CLI or modified through Enterprise Device Manager (EDM).