2011 Switch Upgrade

My infrastructure clearly outgrew the the pair of Cisco 2948G's (10/100) I've been using for years. For general surfing and internet access this is fine however with all the reasonably new VoIP traffic, server backups, my network chokes from time to time.

The public segment doesn't need to be upgraded as the bandwidth I purchase from Comcast is well below 100mb. But, I really don't need a 48-port switch.

The private segment does need an upgrade, and I am using about 2/3 of the 48 ports so I have to be mindful of that.

With a little "eBay research", I purchased two switches at a great price and they are as follows:

The C3524 is to have two vlans - ports 1 through 12 and the odd numbered ports between 13 and 23 inclusive will be vlan1, the public segment, and the remaining ports (even numbered between 14 and 24 inclusive) will be vlan2, my "hotspot" wifi segment. This will leave the SRW2048 switch in entirely for my private LAN.

The reason why I did the odd/even split of the two vlans on the C3524 is so that visually, it's obvious which ports are on which LAN. You can see from the picture to the right that there are two banks of ports, two rows each. Cisco for some reason numbers ports as port 1 on top, port 2 underneath, port 3 on top next to port 1, port four on the bottom, etc. 1-12 on the left bank, 13-24 on the right bank. This odd/even split puts the public segment on the entire left bank and the top row of the right bank, with the wifi segment being the bottom row on the right bank. This makes cabling easier without having to look things up all the time.

The SRW2048 switch is a nice unit, instead of being 1-1/2U like the Cisco 2948G it's replacing, it's only 1U and has four gbic ports for future expansion should the need arise. Unfortunately, the one I bought on eBay has an IP address, login and password that is unbeknownst to me. So, I had to go through this password reset procedure to bypass that and start fresh:

This procedure applies to Linksys models SRW2016, SRW2024, SRW2048, SRW224G4, SRW248G4, and possibly other switches.

  • 1.) Connect the Linksys serial cable that came with the switch between the switch serial port and a nearby computer serial port. For Windows, use Hyper Terminal or VanDyke CRT/SecureCRT. For Linux, use minicom. For other unix types, try cu/tip.
  • 2.) The switch default serial port configuration is set to 38400 baud, 8 data bits, no parity, 1 stop bit, no flow control.
  • 3.) Confirm that you have a valid serial connection by pressing enter a few times. You should be prompted with a login screen.
  • 4.) If you have successfully established serial communication with the switch, reboot the switch by disconnecting and then reconnecting it's power cable.
  • 5.) The switch will begin it's POST procedure as displayed in the serial terminal emulator. Be ready at the keyboard to press the Esc key.
  • 6.) Watch for the following line to appear during the boot sequence. When you see it, immediately press the Esc key;
    "Autoboot in 2 seconds - press RETURN or Esc. to abort and enter prom."
    IMPORTANT: Do not hold down the Esc or Enter/Return key during the boot sequence. Only press the Esc key when prompted.
  • 7.) If you successfully interrupted the boot sequence, you will be prompted with a Startup Menu. Option number 3 will be the "Password Recovery Procedure". Select this option.
  • 8.) The terminal will display, "Current password will be ignored!". Press enter to continue with the boot sequence.
  • 9.) The default account "admin/" will be enabled and you can log into the switch using this account. From here, you can set new accounts without having lost the switch configuration.
  • 10.) After you have configured new accounts and documented the passwords, reboot the switch and log in normally to confirm that passwords have been recovered successfully.
  • 11.) You are done. Disconnect and store the serial cable in a safe place for future use. Be sure to document a login username and password somewhere safe for future reference.

Yes, I shamelessly stole that off the internet somewhere. I'd have given credit for it however I haven't gotten around to look for the author as when I found it I hit "print!" immediately and had at it.

BTW, the SRW2048 is primarily web managed, but there is a limited CLI. Anyway, the console port did not appear to be a standard pinout. I opened the RJ45 to DB9 connector they provided, and discovered it has this pinout:
Pin 1Pin 2Pin 3Pin 4Pin 5Pin 6Pin 7Pin 8Pin 9
xblackyellowbrownred (+green)orangewhitebluex
This is the same as the pinout that was used for the type "A" RJ45-DB9 connector in this article: here. From my testing, you simply need to make two of the type "A" adapters I mentioned in the linked post, attach a cat5 cable to both ends, and you should be able to connect to the serial port. The Linksys uses 38400 baud - unlike the usual 9600.