MPLS

steve-o87

In a recent post in the CCDA - CCDP forum keenon wrote the following:

alot of companies that have this same senerio that your talking about ( multiple sites needing to be secure over WAN) they have been going to mpls.. which is something like frame relay (but not really like it) best i can describe my understanding its like frame because of the tagging of packets but done on layer 3 .. sorry i can't tell you more b/c i don't know alot about it myself but i plan on learning

Im trying my best to understand the concept of MPLS. I understand why it was developed and why it was needed but I cant seem to nail the theory behind it all. Does it work on the same concept of dlci's, vc's and other such things, but at layer 3?

On a good note: I will be writing my bsci in about 4 - 5 weeks. Im excited - Plenty of BGP for me!

Cheers!

MrD

This hits the nail on the head, I think:

Short for Multiprotocol Label Switching, an IETF initiative that integrates Layer 2 information about network links (bandwidth, latency, utilization) into Layer 3 (IP) within a particular autonomous system--or ISP--in order to simplify and improve IP-packet exchange.

MPLS gives network operators a great deal of flexibility to divert and route traffic around link failures, congestion, and bottlenecks.

From a QoS standpoint, ISPs will better be able to manage different kinds of data streams based on priority and service plan. For instance, those who subscribe to a premium service plan, or those who receive a lot of streaming media or high-bandwidth content can see minimal latency and packet loss.

When packets enter a MPLS-based network, Label Edge Routers (LERs) give them a label (identifier). These labels not only contain information based on the routing table entry (i.e., destination, bandwidth, delay, and other metrics), but also refer to the IP header field (source IP address), Layer 4 socket number information, and differentiated service. Once this classification is complete and mapped, different packets are assigned to corresponding Labeled Switch Paths (LSPs), where Label Switch Routers (LSRs) place outgoing labels on the packets.

With these LSPs, network operators can divert and route traffic based on data-stream type and Internet-access customer.