MPLS vs P2P

[sathyasav]

Can any one tell me why MPLS link is preferred than Point to point link.Is it because of cost or because of some other technical reason.

Thanks,

Sathya

[Peter Paluch]

Hi Sathya,

MPLS is just one of many technologies that allow the service providers establish virtual point-to-point links between sites.

You probably mean leased lines when talking about point-to-point links. A leased-line is a separate set of wires dedicated only to you as a customer, interconnecting two of your sites. Providers generally dislike selling leased lines anymore because

• they cannot span over significant distances without requiring expensive signal regenerators, and even then the span is limited
• they are inflexible - any changes to the point-to-point link must be done to the physical wiring
• they are ineffective - the entire bandwidth of this link is dedicated only to you, even if you do not communicate, which is very inefficient for a service provider

As a result, leased lines are expensive and have become less and less used. Instead of these hardware leased lines, virtual point-to-point link technologies have emerged that allow service providers to establish virtual circuits on demand, just by configuring their switching devices, and allowing the existing infrastructure to be shared among multiple customers, utilizing the available bandwidth more effectively. Among these technologies, ATM and Frame Relay have been the most popular, and with the nearly ubiquitous presence of MPLS technology in today's SP networks, the MPLS has become one of the most natural means to provide the virtual point-to-point link service.

So the MPLS is not the only technology that can provide a point-to-point link. ATM, Frame Relay, X.25, to name some of the older (and obsolete) technologies, can do the same. MPLS is just the one to be the standard technology today, used for many applications including L2 pseudowires, and therefore, it is natural to be used also for this purpose.

Best regards,

Peter

[sathyasav]

Excellent answer Peter!!!!

But one more question form your answer,did you say me that the MPLS is shared link but in our office we have dedicated MPLS link in pur office..Am i messing up something?

[Peter Paluch]

Hello Sathya,

Thank you for your kind words. Regarding the "sharedness" of MPLS - the sharing of network resources take places in the service provider's network. It is no different to routing pure IP - may sources can send their IP streams through a routed internetwork, and the routers will process each packet as it arrives, routing it towards its destination. Packets from many sources towards many destinations may be routed through the same links, same devices, and share the same bandwidth. With MPLS, it is very similar, just the MPLS-enabled routers make their decisions based on the label values instead of IP addressing. Again, note that this "sharing" simply fits into the basic scope of packet-switching networks. I did not have any other sharing on my mind.

This being said, service providers have methods to guarantee that your MPLS point-to-point link will be guaranteed a certain bandwidth end-to-end. This depends on your deal with the service provider.

Best regards,

Peter

[Joseph W. Doherty]

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever (including,   without limitation, damages for loss of use, data or profit) arising  out  of the use or inability to use the posting's information even if  Author  has been advised of the possibility of such damage.

Posting

MPLS can often be configured to provide a multipoint link, but this isn't required.  The latter is often one of its major sales features.

MPLS often can provide QoS capabilities that are not offered by the leased p2p link itself.

[tijojoseph]

We have a network of stations which communicate through the MLLN PTP networks. Can we replace the same with the MPLS, by retaining the identity of MLLN, and by reducing the PTP links physically but getting the virtual PTP links. We need to update PTP link details in our internal communication platform. Is the same possible.