Chatting with Yhosvanni from Cuba
Hello Yhosvanni,
I would be happy to provide enough information to you to help in your understanding of the technologies. Very nice to hear from you, all the way from Cuba. I am originally from around New York, and now I am living in New Zealand. Hopefully some day I will be able to visit Cuba.
The cuban national backbone is like many backbones worldwide. SDH/SONET is a great technology for WAN links because it has been designed for WAN. Ethernet on the other hand is slowly evolving into a WAN technology, but as you know, it has grown up in LAN environments. SDH/SONET has features like link monitoring and alarm capabilities. For example, it can signal when there is a defect on the line. This allows the network to respond quickly to the failure.
Ethernet is still growing in these areas. Ethernet OAM (IEEE 802.3ah) will allow Ethernet to provide link continuity checking.
MPLS is where these technologies converge.
Typically, in most modern networks, you will find a minimum of 3 types of functional routers. In MPLS networks that use IP VPNs, you will have Provider routers (”P” routers), and Provider Edge routers (”PE” routers). Then you will also have “CE” routers, which are Customer Edge.
PE routers are the start of the service. They are maintained by the provider as customer aggregation boxes. All customer circuits will logically connect into these boxes. Provider boxes are typically just big and fast routers that switch MPLS packets. CE routers are routers that exist at the customer site.
If the provider is connecting two branch offices, the topology would look like this:
[CE]—-[PE]——[P]—-[P]—-[PE]—-[CE]
The connection between CE and PE may be a mix of technologies: xDSL / Ethernet / Frame, ATM.
The connection between the PE and P is usually Gigabit Ethernet if the PE and P are in the same location. GigE interfaces are usually cheaper than SONET interfaces. The framing chips are cheaper.
The connection between P to P routers is usually SONET, although it can also be Ethernet or various technologies including ATM or Frame.
So let’s think about how Ethernet over MPLS fits into this picture. Usually the main goal of using Ethernet over MPLS is to just provide a big LAN segment or a switching domain over a provider’s network. EoMPLS is usually divided up into two flavors:
pseudo-wire technolgies: (ie. a big long LAN cable )
VPLS technologies (ie. virtual switch )
If the goal is to provide an ethernet segment between two CE’s, then they need to pass Ethernet frames. This could be done over xDSL and ATM. For example, the xDSL could support bridged Ethernet over ATM. The PE could receive the Ethernet frame and cross connect it to the far end PE, where the frame would be switched to the CE.
In locations with native ethernet delivered to the last mile, it is possible to simply provide pseudo wire connections (ethernet cross connects) between ports on the network. Additionally, it is possible to provide virtual private lan services when there are many CE devices that need to be on the same broadcast network.
MPLS VPLS and L2VPN services allow an Ethernet LAN to span countries, and not be limited to the normal limitation of Ethernet LANs. The Ethernet services are also isolated, in a private sense, from other segments or customers, but the use of MPLS VPNs. For example, it is possible to provide any number of private VPLS or pseudo-wire connections on PE devices, and the ethernet frames for customer A, would never be seen by customer B.
Ethernet is cheap, and almost all devices support it. Say for example that you have a company LAN in Havana, and another in Cayo Largo. You want to seamlessly connect these LANs together. Running dark fiber between these locations is too expensive for a small company, so they contact their provider. The provider is able to perform this functionality by creating a VPLS instance on a PE router that is in Havana, and another VPLS instance in Cayo Largo. Then with some protocols (RSVP-TE, MP-BGP, MPLS, OSPF), they are able to link these LANs together as if they were physically connected.
I was in Thailand a few months back and we were building L2VPN with Ethernet over MPLS for most of the circuits. This was far cheaper for customer to purchase and less expensive to the provider than providing long leased line services such as E1 or T1 lines across the country. Many countries are moving towards MPLS, and offering many services such as IPVPNs, L2VPN, and VPLS services because there are different needs with different customers.
In comparing costs of MPLS gear versus ATM/Frame gear; there is another component. Operation expenditures to maintain old equipment, and the cost of training people to work on old equipment is hidden cost in running a business. It is probably too soon to get rid of ATM gear, but companies can start to limit purchases on additional ATM gear. Investing in Ethernet switching gear and MPLS enabled networks allow providers to scale up, and begin to offer many services that their customers will pay for.
MPLS protection (concepts like Fast Reroute, and Explicit Routing) are also big selling points. You can direct traffic to flow down certain paths based on things such as time of day, and least congestion, or any arbitrary policy. This is an advantage to MPLS that SONET/SDH does not directly offer.
Sometimes the newest equipment will be more expensive, but the costs per port are dropping. Especially with Ethernet. A good place to look for pricing will be on lightreading (http://www.lightreading.com) and also to contact some vendors.
Juniper Networks and Cisco make MPLS ethernet components.
Alcatel-Lucent makes ATM gear.
best regards,
truman
P.S. Do you mind if I post this on my website?
Date: Feb 8th, 2007 · Comments RSS · Tags: updateOn 8/02/2007, at 7:19 AM, Yhosvanni Goenaga Fernandez wrote:
Hello Sr.
I read your PowerPoint “Next Generetaion Bras” (Apricot 2006) and I think that you help me about my Mastering.
I am a Telecommunication Engineer and my name is Yhosvanni Goenaga Fernandez.I live in Havana city (Cuba) and I am passing a Mastering in Sciences of Telematic in the Havana Politechnic University (http://www.cujae.edu.cu/).
I ‘m working in an investigation (thesis) about Ethernet over MPLS solution.The cuban national Backbone is implemented over ATM/SDH technologies in WAN and Frame Relay/xDSL in the access network Ethernet is only used in LAN infrastructure. This context does not give me information about EoMPLS because there is not equipments and services based in this technology. By the other hand I neither have EoMPLS simulation software models which can demonstrate the advantages and behavior of this technology versus ATM, SDH and frame Relay.
The problem is I need information about practical implementation of this solution such as:
- Experiences with a real infrastructure based in EoMPLS as well as the different services supported over this technology. This information will help me to expose an example of the functionality of EoMPLS out of my country.
- Where I can found the prices of equipments that support EoMPLS to make a comparison with the legacy ATM and Frame Relay?
- Others.
Please help me.
Warm regards.
Thanks,P.S. Excuse me about my English.
Yhosvanni Goenaga Fernandez
Ingeniero en Telecomunicaciones, MCSE
Especialista en Gestion de Redes Informaticas
Originally published on truman.net. See the archived copy.