Jeffreys Ruminations - Network Blog » Wireless

Vista and WANs

jeffreycentex — Thu, 21 Jun 2007 03:06:23 +0000

There was an interesting article over at Network World that caught my eye today – Vista over the WAN: good but not great. As I have been immersing myself in WAN technologies lately, this has piqued my interest. I admit that I somewhat agree with the reviewer – the experience over the WAN is better, but it isn’t the end-all be-all experience that I think MS was aiming for.

I must admit, though, that the Windows Vista networking experience has not been very positive. Autotuning works well, but forget about using a Vista machine connecting to a Windows 2003 R2 Server or Terminal Server. The TS/RD experience is painful on the LAN due to the “pauses” that autotuning causes. What is weird, although predictable, is that TS/RD connections over the WAN with autotuning “enabled” provides an experience like XP or other W2K3 servers.

Vista to Longhorn Server (Beta 3) over the WAN did provide a significant boost to reliability. In the off hours, I attempted a few tests in connecting and disconnected the WAN session to see how Vista/LH Server handled these interruptions. XP based workstations and W2K3-R2 servers would immediately pop-up a network error and result in mild system hangs and timeouts. I didn’t experience this with the Vista/LHS combination. This would be a welcome relief not only to those who have a WAN setup between branch offices, but also those who are on marginal wireless network connections.

One thing that I have noticed is that DFS Replication in W2K8 Server hasn’t been significantly improved over the offering in R2 server. For our system, I am having to push several GB of replication data across the WAN to our hot backup server (and local branch office server) and I ended up having to disable RDC (Remote Differential Compression) due to the tremendous system loads that this presented to our system. Some of this is due to the type, format, and sizes of data that we produce in this office (i.e., AutoCAD drawings and Access Databases). RDC has to work too much to track all of the changes that are saved every 10 minutes for all of our workstations (10 minutes is the autosave time in AutoCAD). I was hoping for some sort of additional tweaking of the RDC mechanism, but I have not experienced this as of yet.

In summary, there are improvements for WAN-related communication, but nothing that I would call earth-shattering.

WAN Status Update

jeffreycentex — Tue, 19 Jun 2007 03:54:19 +0000

Thanks for all of the help to my request for assistance with out two Tranzeo wireless bridge units. The ultimate answer was so simple that I am still beating my head on the wall about it..

First, for those of you out there reading this who haven’t already met me, I live and work in the Central Texas area. The place where being outside many hours a day in the spring/summer will result in you being “well done”. Well, this contributed to the problem. One of our WAN units is completely out in the open and faces west and gets full sun all afternoon. Ever try going into your car on a hot day with a window pointing west? It is an oven. Well, that was what was happening to the WAN unit. However, it was designed to work this way. The problem was more related to our signal strength combined with the heat. Our two units are only a quarter of mile apart and clear line-of-sight. The problem was the way we were overdriving the units. I had the power cap set to the full 30dbm on both ends. This was getting me a normal signal strength between -48 and -53dbm. However, this was causing the units to be completely overdrived and then the signal completely dropped off, resulting in the -90’s we had seen.

The solution? I changed the power cap from 30dbm down to 8dbm. Now I get a signal averaging -62dbm and I’m not overdriving the unit.

Woohoo.

This has been a pretty nasty thorn in my side lately. I have been covering it up by DFS replication, but the link had to be fixed and it had to happen soon.

Now I can sleep better.

Request for Help: 802.11A Wireless Bridge Interference

jeffreycentex — Thu, 26 Apr 2007 03:09:29 +0000

OK, for the second item of the day, I want to make a general call for help in troubleshooting a particularly nasty 802.11A problem I am seeing between our office and branch office (basically, 1/4 of a mile down the road with LOS).

The wireless network works flawlessly for about 166 hours a week. However, everyday at about 4 PM, we get a few glitches in the data stream. When I look at the wireless performance data, I am getting about 15% of packet retries for about 5 minutes. This affects only the data (LAN) transfers and DFS replication. VOIP does not seem affected at all. On Wednesdays, however, this packet loss lasts considerably longer (for about an hour or so). This wreaks havoc with our CAD files (which are still being sent over the WAN).

During Normal Operations:
Strength: -53 dbm
Noise Level: -103 dbm

During the “Glitch”:
Strength: -90 dbm
Noise Level: -103 dbm

I have switched to all of the channels that the device (Tranzeo TR6) will support to no avail…

I’m working with the equipment provider, but I wanted to see if anyone out there has seen this..

I have tried to eliminate other interference sources, but there isn’t much that would cause problems throughout the 5 Ghz band…

Thanks for any help.

Info on WEP Cracking

jeffreycentex — Tue, 24 May 2005 07:48:21 +0000

John in Oregon has posted a few links to some articles on Tom’s Networks that describe how easy it is to crack the WEP encryption many people use on their SOHO routers…

Tags: WEP

WPA PSK Cracked…

jeffreycentex — Tue, 16 Nov 2004 08:27:30 +0000

Alas, that temporary security solution for SOHO and home wireless networks — WPA-PSK (Pre-Shared Keys) — has been cracked… Well, we knew it was inevitable. Unfortunately, for the vast majority of small networks — like those in homes and VSBs (very small businesses) — there is no better solution for the time being… Like the article states, 802.1x solutions are not vulnerable to this cracking. However, implementing the required Radius or IAS solution is beyond what home and VSBs can implement.

Any suggestions out there?

Check out the article at http://blogs.zdnet.com/Ou/index.php?p=9 and weep…

WPA/PSK Support on Windows 2003 Server – Not Yet

jeffreycentex — Fri, 02 Jul 2004 06:05:55 +0000

I also wanted to pass along an update I got from PSS concerning WPA/PSK support on Windows 2003 Servers.. Regardless of what you may read in the Knowledge Base, there are no updates or hotfixes as of yet that will enable WPA/PSK on Windows 2003 Servers short of installing an upcoming service pack… This question has popped up a few times in the networking newsgroups, so there was some question about this.