Shr Dispute in Cisco switches

I did some tests on some Cisco switches the other day and came across an error I have not seen before. Then I looked into a port's spanning tree I found a port was blocking with the message Dispute Shr. I have not seen this message before and could not find anything when I tried to Google on it.

nede#sho span int g0/1

Mst Instance Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- --------
MST0 Desg BLK 2000000 128.1 Dispute Shr
 

So I had to investigate this. Luckily for me Cisco have very good documentation. In an article discussing something I found the answer I was looking for.

A dispute flag appears when a designated port receives inferior designated information until the port returns to the forwarding state or ceases to be designated.

The Shr simply indicates that the port is on a shared network. The reason for that is that the link is half duplex.

Vista wireless and lag

Have you noticed that Vista and wireless often looses connection to the Internet (and corporate network). This is often seen with games and real-time applications like VoIP products.

Windows Vista doesn't works with the optimal wireless setinngs. Some of this settings are causing 1,5sec dropouts with many wireless cards, which are appearing every 30-60sec. This dropouts are very hated in the gaming community and if users are using voice over IP applications or other realtime protocols.

Here you can find a solution for your problem.

WAN optimization with Riverbed

Today I had a chance to work with a product for WAN optimization for the first time. I ran a live demo at a customers site.

	It works. At least if your network traffic is predictable and repetitive. Most networks are, as clients tend to do much of the same.
	It is too expensive for most customers. It is really hard to justify the cost and more importantly the return of investment.

Acceleration of SSL traffic

Rivedbed promised to support SSL in version 4 of their software. I can't wait to try this one out. It only requires you to install your private key on the box inside your datacenter.

Steelhead appliances now accelerate encrypted (SSL) traffic, using all of Riverbed's algorithms to deliver LAN-like performance for those key business applications.

Of course this won't work for external web sites as you don't have access to private keys. But for intranet applications this is cool!

Exchange 2007

Exchange 2007 supports encrypted MAPI connections. Much details on this issue is not known at this point.

Based on our testing, we've found that the encrypted connections that appear by default in an Exchange 2007 environment with Outlook 2007 clients are a proprietary "MAPI encryption", not SSL.

Impression

Riverbed Steelhead appliances are easy to set up and work without the need to do much. Just make sure the traffic is unencrypted and leave the rest to Riverbed.

RiOS 4.0

I will do a new lab with RiOS 4.0 when it is released and do tests on Exchange, Sharepoint and web traffic. All SSL encrypted. If you are curious about this, please leave me a note.