Tips #3 - Documentation on Networks and Vlans

As your home network grows, so does the level of confusion about what was wired up where and when.  In general, you can document what happened through a journal about changes you have made to the network.  But filtering through that journal when you are in the midst of making lots of changes will be very time consuming.  It is better to keep the information in a separate list.  Normally, devices that you have in the network will retain certain Ethernet addresses, but sometimes the wiring will change and the placement of the equipment as well.  There are four specific documents that I use to document different views of the network and provide an easier way of changing the layout as my equipment, equipment placement, wiring, etc. change over time.  In my case, I keep the four documents as notes in my CellPhone under a classification of HomeNetwork.  The four documents are:

1. Current IPs in the Network
2. Patch Panels
3. Cable Connections
4. Home Vlans

These are described below:

-- Current IPs in the Network

• The "Current IPs in the Network" and "Home Vlans" rarely if ever change.  However, if I move a piece of equipment in my network, "Patch Panels" and "Cable Connections" will be altered.  If I move a piece of equipment from one vlan to another, by definition the "Current IPs in the Network" will change, along with notations about the connections in the other documents.
• The "Current IPs in the Network" note should contain all known IPs that you have in your home network.  I have even included IPs from equipment that are connected to multiple vlans.  That way the document is all inclusive.  I also make sure that all IPs that show up in my network are known.  If it isn't on the list then I know someone has attached themselves to my network that I don't know about and I go and hunt down what it is.  Rogue pieces of equipment or IOT equipment that doesn't behave I disconnect.

-- Patch Panels

• I have already described how I label patch panels here.
• The "Patch Panels" note documents the infrastructure of the network
• The "Patch Panels" note is broken down to each patch panel with what is connected by port number on that patch panel.
• The "Patch Panels" not does not contain any information about what equipment the port connects to, i.e. with a patch cable connection from the device to the patch panel, only documentation of what connections exist.  
• There is an exception where the patch panel port actually goes directly to a device and is designed to be there consistently.  For instance, I have a PiHole in my network and that is connected behind one of my patch panels.  So for the label on that patch panel, I label the port as "PiHole", e.g. PP#3-7 is labeled PiHole so I know where the port goes to.
• I use the term "patch to" when describing the use of a patch cable at a specific patch panel.  For instance one of my patch designations at patch panel 3 port 11 is "PP#3-11 - PP#1-10".  I can usually read where the port is going by looking at the actual patch panel.
• If I have a patch cable going between ports on a given patch panel, my "Patch Panels" note will have something like this: "PP#1-10 - PP#3-11 (patch to PP#1-9)" for the designation on patch panel one port 10, and I will have "PP#1-9 - PP#2-6 (patch to PP#1-10)" for patch panel one port 9.  Note that this shows where my patch cables are and how they connect.  I can always go to the "Patch Panels" note and trace from one point to another to understand where the cable ends.
• If I move/remove the patch cable from a patch panel, then I can simply modify a couple of lines to show how things are connected.  Again, the idea is to be able to trace to the end.
• Note that I do not list any patch cables from devices that are plugged into a port on one end or the other.

-- Cable Connections

• The "Cable Connections" note is where I list the patch cable connections to devices.  It also designates a logical connection to an end point.  Normally there would be a patch cable from a device, and on the other end of the trace there would be a connection to a different device.
• The "Cable Connections" note is grouped by device which allows me to immediately find out where the device is connected by port number.
• In the "Cable Connections" note I describe on a device port where the connection ends up.  For instance, I have a connection from my main switch which is a "trunk" connection to another switch.  The way that I write it is as follows, using the last portion of the switch IP addresses:  ".119-15 - to PP#3-23 -> .118-1 [6/T]" which is a shorthand way of listing where the connection ends up, even though the actual trace through my network goes through 3 patch panels.  I can trace the physical connections through the "Patch Panels" listing and I note the vlan trunk elements (a tip on vlan nomenclature is here).  Correspondingly, I look at the port for the receiving switch and it looks like this: ".118-1 - to PP#4-X -> .119-15 [6/T]" which indicates the reverse direction.  Again, I can look through the "Patch Panels" listing and discover the physical connections through my network.

-- Home Vlans

• The "Home Vlans" note is where I give a listing of each vlan used in my network, including why I have the vlan, what DHCP server address is used, and what DNS server address(s) are used.
• The "Home Vlans" note also contains a line which lists the trunk line vlans for the normal case.