Tuesday, January 29, 2013

Xbox Live - Cisco Wireless

So I had this problem creep up ever since the students showed back up on campus for the spring semester.

From the trouble ticket: "My Xbox won't connect to Live"

What? What do you mean it won't connect. I saw xboxes connected to the wireless network all over campus. Then the flood of tickets stated coming in. Most of the students know by now that they need to register there xbox on the network via a helpdesk ticket. This is due to the problems with DHCP fingerprint with our registration system, Packetfence. If you want to know more about that read some of my other posts or encourage me to finish some about the updated version.

Anyway back to the problem at hand, Xboxes not connecting to Live. I have tickets out the wazoo about them, grumble grumble, search up and down. MS points to reboot your router and reconnect. Yeah that will happen.

So last friday, I got an xbox 360 from a student to test with. Connects to Wifi, but that is as far as it will go. Connected to the wired network, tests clean to live, except the NAT, which is a fact of life. Back to the wifi, tests show no response to icmp. Hmmm. Without dancing through some hoops, I do not have the proper tools to capture the wireless traffic. Ok lets do the next best that I can do, track xlate and conns through the firewall and then compare them.

Shortened and simplified
Wired side:

  • Client builds xlate
  • UDP to Live address
  • TCP connection to several other Live addresses
Wireless side:
  • Client builds xlate
  • UDP to Live address (Same address as wired side)
  • Teardown connections - Nothing more

So this behavior has me thinking, am I fragmenting packets? But why? Where?

I finally came across the following article after exhaustive searching: http://revolutionwifi.blogspot.com/2010/07/fragmentation-in-controller_02.html 
Andrew refers to LWAPP Fragmentation in  L3 LWAPP transport - Check doing that. Ok so what I am using. I read down farther to the prevention, and I check my controllers/ap's. Adjust TCP MSS not checked on any of my AP's.

Enabled that on all the ap's on the controllers and then checked back with students. 

Responses back, "It's working, I can connect to Live"

Why did this come up? 

After last semester I upgraded the code from 6.0.xxx to on my WLC's because of the MS Windows 8 issue. So either this was un-done in the upgrade or was not a factor in the previous code. Not sure, but since I have a fix, I am not going back to find out. Time to move forward with the many other projects.

Hopefully this helps someone in the future. Since connecting an xbox to a enterprise wireless network is not really covered in MS help.

Also I would like to thank Andrew von Nagy @revolutionwifi for his blog article, Josh O’Brien @joshobrien77 for pushing me to post and to keep looking. 

Note: This may need some edit but just trying to actually push it out the door before it ends up on the cutting room floor.