MPLS is becoming the WAN of choice because of its versatility. The MP of MPLS stands for Multi-Protocol. MPLS networks aren’t fussy about the type of traffic they transport. Each packet gets a wrapper label and the LS or Label Switching makes sure it gets from source to destination intact. There’s another networking technology that is also coming on strong. That is VPLS or Virtual Private LAN Service. VPLS is an Ethernet WAN service that connects multiple company LANs as if they were one much larger LAN that includes sites all over the world.
“That’s it,” you say. “I want VPLS not MPLS.”
Ah, not so fast. VPLS isn’t a network by itself. It needs MPLS networks to transport it. VPLS is a service running on MPLS. It’s one of those multi-protocols that MPLS networks carry so well.
Technically, VPLS uses a concept called pseudo-wires. Pseudo what? The name suggests what this is. It’s the emulation of a wired connection through a network. A real wire would be used for point to point private line service. You would lease the line and it would be “nailed up” or dedicated to your exclusive use for the duration of the lease. Pseudo wires are a way to establish private lines within packet switched networks. The idea is to create a transparent wire that can be used to carry a service from point A to point B.
Think of a pseudo-wire just like a length of Ethernet cable on your LAN. The wire doesn’t interfere with your protocol. The pseudo-wire doesn’t interfere with your protocol on the WAN. By establishing pseudo-wires through the MPLS network, it is possible to string virtual LAN wires hundreds or thousands of miles long. This is one of the tricks behind extending your LAN beyond the boundary lines of your property.
The other trick is for the network to emulate a switch or bridge to create a meshed network so that all locations can communicate as if they were on a bridged LAN. VPLS is a multi-point service. If all you wanted to do is connect two locations, you’d probably just get Ethernet Line Service using a pseudowire through the MPLS network.
The MPLS network can be thought of as a cloud that transports data and creates a multipoint switched network for interconnecting two or more business LANs. That can be anywhere from a few locations in the same state up to hundreds or thousands of locations across the globe. Because it is a cloud, you don’t have to worry about how the packets get from anywhere to anywhere. That’s the network provider’s job. All you need to do is get to that cloud from wherever you need a connection.
Those “last mile” connections can be a variety of protocols and a variety of bandwidths. If you want VPLS service, you’ll need to have Ethernet connections in the last mile. Those can be Ethernet over Copper, Ethernet over Fiber, Even Ethernet over DS1 or DS3 in situations where EoC isn’t available.
This brings up another option. If you don’t need layer 2 connectivity between LANs and simply want a WAN connection to transfer files between locations, you can set up a MPLS VPN service. This can use layer 3 routing just like you might create with a collection of private lines or over the Internet. One advantage is that you can use any protocol connectivity, such as T1 lines, DSL, SONET fiber optic and so on. Each location can have a different type of connection. The network will accept your packets, wrap them in MPLS labels and get them where they are supposed to go.
How about your WAN connectivity? Could you do better regarding bandwidth, quality of service or cost? Get competitive quotes for VPLS over MPLS and MPLS VPN network services to check available options for your business locations.
Note: World map graphic courtesy of Wikimedia Commons.
