Tag Archives: service provider

Cisco Layer 2 Tunneling

To a student of networking the OSI model can be a little hard to appreciate until its application is actually seen a few times in the real world.  Likewise understanding that you can grab frames or packets and encapsulate them inside other higher layer protocols is also confusing to the newbie.  An Ethernet pseudo-wire is a great example of this.  Essentially, you can capture an entire Data Link layer frame as it enters an interface, encapsulate it, and deliver it out another interface no matter what type of network you have in between.  Cool stuff right?  Let’s dive in and … Continue reading

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802.1Q Tunneling AKA QinQ

You are probably familiar with VLAN tagging on switch trunks and how it can be used to separate physical infrastructures into multiple logical networks. With the explosive growth of Metro Ethernet connections the ability of site to site layer two connections has now become common. It’s easy for organizations to implement as network admins are already familiar with Ethernet as a LAN protocol. The setup is simple for the customer but a bit more configuration is needed on the service provider’s side if the customer desires VLAN tagged traffic to flow over the site to site link. Lets take a look! Continue reading

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