Re: need to compare existing l2 transportation solution

Dark fiber is really a physical layer offering, not a L2VPN
technology, so I'll focus mainly on the others. You can use dark
fiber to connect endpoints using point to point routed links, Ethernet
VLAN trunk links, etc., depending on the application. It could be a
service provider's managed dark fiber service based on DWDM.

The pros and cons of L2VPN really depend on what you're trying to
accomplish. It's important to understand how different tunneling
technologies are used and how they impact the network design. Things
to ask yourself when selecting a tunneling technology are -

1) How does the tunneling technology impact the application that's
riding on top of the tunnel - will encapsulation overhead (MTU) or
packet reordering be a problem? What are the security requirements
i.e. does data need to be encryped? What type of traffic does the
application send and does the tunneling technology support it?

2) How does the tunneling technology scale and can it be effectively
managed? Is point to point connectivity required, or is multipoint
connectivity required? Is a full mesh of tunnels required, etc.? You
obviously wouldn't want to manage a full mesh of p2p pseudowires for
connecting 1000 sites.

3) How will the tunneling technology interact with routing? How is
traffic steered into the tunnel? Do you need to configure routing on
top of the tunnels to provide reachability through them?

Having said all of that, here is some info on these different types of
L2VPN technologies that you mentioned.

Point to Point
--------------------

-VPWS is another term for point to point L2VPNs or pseudowires. This
refers to AToM (Any Transport over MPLS), which can transport Ethernet
(EoMPLS), Frame Relay, ATM, or HDLC over an MPLS core. VPWS also
refers to L2TPv3, which can transport the same L2 technologies over an
IP network.

-EoMPLS is a specific type of L2VPN, which obviously requires MPLS
forwarding (possible forwarding plane change) and provides transport
of Ethernet frames over the MPLS network.

Multipoint
--------------

-VPLS also requires MPLS forwarding and provides connectivity to a
common Ethernet broadcast domain. For example, if you need to connect
multiple data center sites to the same broadcast domain, then you
could use VPLS. This scales much better than VPWS. Provides full
broadcast overlay on top of a routed infrastructure.

A couple of good CP books are Layer 2 VPN Architectures and Comparing,
Designing, and Deploying VPNs.

Ronnie

On Sun, Mar 14, 2010 at 12:40 PM, ehtesham ali
<conect2ehtesham_at_gmail.com> wrote:
> HI expert
>
> It would be great if i get a comparison on the following technologies .The
> pros and cons of the following when designing.
>
> EoMPLS
>
> VPLS
>
> VPWS
>
> dark fibre
>
> L2TPv3
>
>
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-- 
Ronald Angello
Network Architect
CCIE 17846
CCDP, CCIP, CCNP
Blogs and organic groups at http://www.ccie.net