networking

Ruckus ICX 7150-C12P Switch Repair

A while ago I purchased a Ruckus ICX 7150-c12p off eBay to use at home. It gives 14x1gb/s ports, and 2 SFP+ ports. The SFP+ ports are limited to 1gb/s by default, and there is a honor system license for upgrading them to 10gb/s. These switches go for $600 – $1200 depending on where you get them and which license you get with it (1gb/s vs 10gb/s). The switch is also POE, and can do 4 POE+ (30 watt) ports. I had one of these switches and it worked great. I wanted to get a second one to replace the WiFi link I was using across my apartment with a fiber link.

Instead of paying ~$250, which was their going rate on eBay; I saw a forum post about replacing this models power supply, and thought I would give that a shot. I got a broken switch for $45, and then a PSU for $50. The PSU I used was a SL Power LB130S56K 56V 2.32 130W. Armed with someone’s photos of doing this repair it ended up going fine. The hardest part of the whole operation is that the pins going onto the main board are reversed from what the power supply comes with, so you need to flip them. I have been running the unit for almost 2 years now without issue.

This model of switch is great because of its features and is fanless. The fanless-ness part of it is nice for homelabs near your desk, because the switches are silent. Because they are fanless, they cant have anything put on top of them, and need some room to breath. I think a lot of the ones you see online dead are because someone didn’t give it enough air, and the PSU died. Note when looking for a similar dead switch on eBay, you really want the seller saying “when plugged in nothing happens”, not “it periodically blinks” because that could be bad ram and its in a boot loop.

Having run two of these switches for over a year, I can give some feedback. I really like them. I have the two I have in a stack, I login once and manage both. When it comes time for firmware updates you SCP the file to the management IP, and it downloads the file to both, and then flashes and reloads. I came from using Cisco gear usually, or sometimes Arista; the CLI is a bit different, and Ruckus handles VLAN setup a bit weird, but once you get used to it, it makes sense. They are solid switches, with POE, that you can set and forget for a while.

Broken guy
Easy to open screws
de-lid-ed switch
Old PSU
There is a little plastic cover that folds over it
Thermal pad on bottom of PSU
This little caddy holds the PSU
Had to switch the PSU Pins, look at the forum post I am not 100% sure this is before or after
Old homelab about 2 years ago, I went a bit crazy getting broken ones to repair, gave one to my brother, other had bad memory

Super Conduit

Due to the high latency of the lines between my works offices, file transfers can be slow. There are settings in Windows Vista+ systems that can allow the TCP window to grow, and allow much higher utilization on these lines. I call it Super Conduit. This may be possible on *nix systems, but the way this tweak works is that it tells the other side it will be doing this tweak. That means that both sides have to be at least Windows Vista Kernel, (Server 2008 works) that also means that linux file servers will not work because them seem to be linux machines with SMB. This should be done over wired connections, because the packet loss on wireless hurts these connections more than anything else.

With the “autotuninglevel” change, I have seen speed changes from a 1megabit a second line go to 150-200 megabits a second.

WARNING: Windows Vista/7 IP stack can not handle changing this setting and using normal connections, meaning once this is done usually the internet stops working until the setting is reversed. Windows 8+ seems to have no problems with this setting, and the internet; it just makes Win 8/8.1 more awesome than it already is, which is pretty awesome.

  1. Login under a administrator account to the Windows machine
  2. Open ‘cmd’ as a administrator
    1. Title bar should be “Administrator: C:\Windows\System32\cmd.exe”
  3. “netsh interface tcp show global” will show the current settings of your machine
    1. Command Line Status
  4. “netsh interface tcp set global autotuninglevel=experimental” enables the majority of what you need for faster transfers, all you will get back in response is “Ok.”
    1. Image2
  5. Another setting I have used in the past is “netsh interface tcp set global ecncapability=enabled” this adds a flag to the packs that tells routers “I dont care if I get slowed down, please dont drop me completely”. The problem you run into with large TCP windowing is one dropped lowers the TCP window size a lot and slows the connection making it a lot more spiky. This command doesnt always help, but setting it hasnt hurt in the past.
    1. Image3
  6. The “rss” receive-side scaling state should be set to enabled, that should be the default. This allows the receiver to do these types of conenctions.
  7. When you are done your transfer just run “netsh interface tcp set global autotuninglevel=normal”

 

Troubleshooting Notes:

Windows 7 seems to act oddly when starting to use this setting, so I would enable it then restart the machine. I believe that cached sessions already in progress do not take the new setting.

 

YAY MATH:

http://bradhedlund.com/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/

Default window size: 65536 bytes * 8 = 524288 bits

73ms latency between cross country offices, 524288 bits / 0.073 seconds = 7,182,027 Bits throughput, theoretically. 897,753 B/s, max.

This setting increases that window size to something larger, much larger, and thus gives better speeds. The only interesting downside is that since the TCP window is big, if a packet is then lost, TCP resizes the window to a much smaller setting; forcing the window to climb again.

That is a 1GB link going across the country.

That is a 1GB link going across the country.