It has been a long time since my last post, but I am glad to share with you my notes on the subject as it is helps me also get better understanding of what I am reading and testing in my lab, and I know it is not relevant to the current R&S lab or Written material but my guess that not in the far future it will be very relevant as it is a very important subject that is growing rapidly and new technology like Metro Ethernet are more and more taking the place of Frame Relay ATM technologies. MPLS (Multi Protocol Label Switching) or as I would like to call it Layer 2.5 as it is fast as layer 2 and intelligent as layer 3 but neither. Some Basics components LSR (Label Switched Router) Edge LSR same is LSR but working in the border or Edge of the MPLS cloud. There are 2 MPLS concepts (modes) MPLS frame mode and MPLS cell mode. the 2 are very different and I will not get into the bit and byte now of each but you need to remember that each one has very different behavior. MPLS is a high performance way to move a packet from one point to the other over routed network with no overhead of routing tables. I have structured a lab on Dynamips based on Cisco very nice article you can see for your self in no more then 10 minutes a 6 router lab schema working with MPLS, try you will fall in love when you will see how easy and nice it is working.