j2sw’s blog

DOT1Q tunnel is a way of allowing any vlans to pass though a provider's network. a QinQ tunnel is also referred to as "VLAN Stacking".  This way you do not have to worry about overlap of vlans you would have in a normal switched network.   QinQ is used quite a bit in Metro Ethernet because it offers the following benefits:
-Security via isolation of customer traffic
-Backward compatibility preserving existing customer VLAN structures
-Simplicity via unburdening the service provider from configuration management of CE devices
-VLAN scalability (with up to 4K private VLANs per subscriber for up to 4K subscribers)

What happens is the end user network "wraps" their vlans within the access vlan at both ends.  From the send side it works like this:

Packet leaves the customer's switch on vlan 10 (see our example below).   This packet might contain information for a vlan of the customer's choosing. In our example we will say the customer is wanting to pass vlan 30 through to the other side.  When it enters the provider's switch on vlan 10 it is allowed to pass through the network over the trunk.  The provider just sees this as vlan 10.  Once it leaves the trunk port into the customer switch on the other side it is "unwrapped" from VLAN10. 

Dot1q

In order for QinQ to work across the entire network and additional overhead on the MTU must be accounted for.  Most ethernet providers doing multiple IP-IP tunnels and other such things already are raising the MTU to account for these so adding QinQ is not that big of a deal.  With some Cisco switches you are able to raise the MTU on a per port basis if need be.

I am wondering if the majority of the internet cares about an e-mail discussion being "top posted" or not.  Thoughts? opinions? It seems this comes up less and less these days. Was wondering if those who do bring it up are the die hard old-timers.

techmeme.com has no stories about twitter. Holy cow. They seem to love stories about twitter.

www.cellcrypt.com
UK ‘stealth mode’ startup Cellcrypt has started touting a new encryption system that sets out to solve a security problem most companies would rather not think about – insecure mobile phone calls.

Random Cisco Tip

To restart or reboot a Cisco in a certain number of minutes, in enable mode:
Router#reload in 5


http://news.techworld.com/operating-systems/3201232/snow-leopard-update-in-the-works-already/

One of the reasons I have been holding off on my day-to-day machine.

I recently filled out a University of Phoenix online thing to request more information.  Since Friday I have received 27 calls from them!  To me this is a little much, especially over a Holiday weekend.  They seem like more of a used car lot than a University at this point.  27 calls in a 3 day period is a little much.

http://blog.backblaze.com/2009/09/01/petabytes-on-a-budget-how-to-build-cheap-cloud-storage/

Pretty good price for what you get

Recently I signed up for the paid skype service. I received my own telephone number and wanted the ability to forward unanswered calls to my cell phone.  The Skype documentation leaves much to be desired when it comes to this.

Since I am a United States customer I had to look at the forwarding from the Skype perspective.  Since they are a U.K. company the calls are actually forwarded from the U.K.  Once I came to this realization I used http://www.countrycallingcodes.com/ to look up what the country code was. This lead me to the following string which i entered: 00121XXXXXXXX.  Skype recognizes this as :+121XXXXXXXX.

Hope this helps some of you.