Sysadmin’s Guide to Network Mapping
It's important to understand why every administrator should map out the networks that they monitor. It's equally important to know what is network mapping and how to go about drawing up your map. This includes which devices to include in your map and which tools to use.
This article provides a breakdown of all of this information. It is designed to give administrators a solid understanding of how to create a network map.
Throughout history, people have created and used maps for navigation. Maps help us understand where destinations are located and how to reach them. To communicate this information effectively, maps need to be drawn correctly and labeled accurately. It's also important that maps be kept up to date, because terrain often changes.
In the networking world, we use maps for similar purposes. Network mapping helps administrators perform the functions of their jobs more efficiently thanks to having properly organized data at their fingertips. In environments where multiple administrators work on a single network, a network map helps everyone involved understand how the network is laid out. When the control of a network is transferred to a new administrator, network discovery becomes much easier with the help of an efficiently designed network map.
Why to Have a Network Map
Before creating a network map, it’s important to understand the specific reasons why you need one. Those reasons include having an understanding of the IP addresses that are used in your network, having an inventory of hardware assets, and getting a step ahead when troubleshooting issues.
A Record of Used IP Addresses
One of the most frustrating challenges network administrators face is having to troubleshoot IP address conflicts that arise when a device with a static IP address tries to claim the same address as another device (which may also have a static IP, or could have received a dynamic address assignment from a DHCP server that was not aware of the conflict). The best way to avoid these conflicts is to have a record of the addresses that are already being used.
Devices that typically have static IP addresses include the following:
- Network Equipment
When you start network mapping, you should include a record of the IP addresses assigned to these varieties of infrastructure. With this information, when IP address conflicts occur, they can be resolved fairly quickly.
An Inventory of Hardware Assets
It's important to have a record of the equipment that you have on your network. This information will help you keep things organized and up to date.
Here are some of the advantages of having an inventory of hardware assets:
- Preparedness for end-of-life dates. It's good practice to replace aging equipment before it fails. Having an accurate inventory will help you know when to replace aging equipment.
- An understanding of upgrade needs. When bottlenecks or other slowdowns occur on your network, you need to know where to look to address the issue. Having a map of all your equipment will help you diagnose issues and determine where replacements need to be made.
- Network security verification. You need to know that your system is secured. Having an inventory of your equipment will help you verify that all security patches have been applied. It will also help identify where new security loopholes may exist.
Assess vulnerabilities and threats, network security, workspace and equipment security, documentation, and more. The pack includes:
- a ready-to-print PDF file
- an Excel file to help create a customizable assessment resource
A Guide for Troubleshooting
When you have network issues, troubleshooting is much simpler when you have a map to work off of. This is especially true for situations where the person doing the troubleshooting isn't entirely familiar with the network.
Here are a few advantages that network mapping gives you when troubleshooting:
- A visualization of points of failure. If you know that a specific region of your network is reporting issues, a map will help you regionalize the issue and give you an idea of the possible points of failure.
- An indicator of trouble spots. A good network map can help to predict future issues. A proactive network administrator will be able to use the map to find vulnerabilities and address them before issues occur.
- An idea of the affected area. When issues arise in your network, they generally don't happen on an island. You need to know where issues will trickle down to impact other devices. Having a network map will help you obtain an understanding of what else may be affected when trouble arises.
Devices to Include in a Network Map
So, what is network mapping? Which devices should it include?
Ideally, your map should be comprehensive and all-encompassing. As long as things don't get too confusing due to over-complication, you want to include as much information as possible. Here are some ideas on the devices that should be recorded and some tips on how to document them properly.
Most of the clients on your network will probably be personal computers. Recording each one may seem tedious, and keeping your list of PCs accurate and up to date may be difficult. However, this is still an important piece of the process.
Here are some things to take note of for PCs on your network map:
- IP assignment. Have a record of each PC's IP address if it is assigned a statically. If not, indicate that it is configured for DHCP.
- Uplink information. Confirm whether the device has a wired or wireless connection. If it is a wired connection, confirm where it connects to the rest of the network.
- Software information. Your map should indicate each PC's operating system. Any business-specific software installations can be listed as well.
- Hostname. Every computer should have a logical hostname. Each PC on your network map should be labeled by hostname for easy recognition.
Printers are an important part of your network map. Each printer’s information is often needed when configuring clients to be able to send print requests to these devices. Because of this, the printers on your network map may be referred to most often.
Here are the specifics to take note of when it comes to printer mapping:
- Record each IP address and hostname. Both identifiers should be listed for reference.
- Purpose. It's a good idea to describe which types of print requests are sent to each printer. If the printer is using a special type of paper, this should be indicated as well.
- Physical location. Your map should make it clear where to find each printer. Department, floor, and the specific room can all be recorded here.
- Make and model. The printer make and model are used for driver lookups and installation. It's also important to know when ordering parts or additional toner.
- Tray assignments. Have a simple listing of the number of trays and the purpose assigned to each tray.
You will probably have just as many VoIP devices on your network as computers. As networks move away from PBX phone systems and toward IP phones, these devices are very important to include in your network maps.
Here is the information that should be included for each VoIP device:
- Extension number. Each phone has an extension for direct dialing. Having this number on record helps with configuration and for contacting the specific phone when needed.
- VLAN ID. Your IP phone may be on a different virtual network than the rest of the clients. This network will be labeled by a numerical identifier, referred to as a VLAN ID. Noting this ID is important for clarity.
- Physical location. This is simple and obvious, but important. You need to have an idea of how to locate each device physically.
While the devices in your network closet aren’t considered clients on your network, they shouldn't be forgotten when you create your network map. Because the functionality of these devices is critical to your network's performance, having these items mapped will help speed up resolution times when network issues occur.
Here are the statistics to keep in mind when mapping out these devices:
- The number of connections. Routers and switches all come with a specific number of available ports. Having this information on your network map will give you an understanding of what you have available, and when an upgrade may be needed.
- Connection speeds. Your network throughput will only be as fast as your slowest allowed connection. Switches and routers come with different speed specifications. Understanding the speeds that each of your devices allows will help you when it comes time to make infrastructure upgrades.
- Uplink information. The way in which each device connects to others should be documented clearly. It’s important to have an understanding of how data travels through your network, and how everything is linked together.
Tools to Use
When first building your network map, you have to gather as much information as possible. The best way to do this is with network scanning software. There are a large number of tools available online. Be sure that the one you choose reports the following items:
- IP address and MAC address. Each device’s address identifier must be listed.
- Vendor name. For the purposes of device identification, it's good to know the vendor (i.e., the hardware manufacturer) associated with each IP and MAC address.
- Open ports. A listing of open ports helps paint a picture of each device's purpose.
Having all of this information from your network scan will help you start your map. You'll have a good amount of information that you need all in one place, and it will help verify that nothing is forgotten.
Network Mapping Software
Along with good network scanning software, you need to use the right software package for building and creating your network maps.
- Easy to use. You need this software to be usable by not just you, but other people who need to use it in the future.
- Customization. Every network is unique. Adding customization such as unique imagery and categories helps to clear the confusion.
- Proper Information Handling. You want to be able to store all of the information you need for each device in a readable way.
A clean, properly designed map will help everyone understand what's going on with your network.
Network mapping can seem tedious and time-consuming. Having a record of the IP address used on your network and an inventory of your assets will help you troubleshoot issues in the future. When building your map, you must have each device recorded properly, and use the appropriate software for gathering and organizing your information. Once your network map is complete, you and your network will be in a much better place.