MPLS 4

[burtsbees]

I feel dumb asking this, but it was not something I studied while studying for CCNA or CCNP...I know what it basically is, but I do not know what exactly it is for...it looks to be something that is implemented in a network that has converged applications, like voice, video and data all in the same network, requiring certain QoS configurations. But I also read that it is implemented on the ISP end...but I also hear different from that. Anyone have some good links or books on the subject? Is it fairly new, or not so new, just now becoming mainstream? And most importantly, what is Cisco's role in this technology (what sort of configs are considered to be MPLS, etc.)? Thanks.

Burt

 

[jneiberger]

Unless you work for a service provider, chances are you won't have to directly configure MPLS in the near future. It's primarily a technology used inside provider networks. It can be used at layer three, in which case your routers would peer with the provider's routers and actually exchange routing information. From your perspective, your network would appear to be the only one on their equipment. However, they're actually carrying layer three traffic from multiple customers, each in its own space.

It can also be used at layer two, in effect creating virtual PVCs much like frame relay. This has the benefit of being very similar to existing frame relay or ATM networks from a customer perspective and you don't have to deal with route peering with the provider. However, it's not nearly as flexible as layer three implementations that can allow one-hop any-to-any connectivity.

MPLS is great for multiservice traffic because it is easy to classify and prioritize traffic. You can even give real-time traffic an entirely different path than that taken by non-real-time traffic. The provider has a great deal of control over such things.

MPLS can also carry pretty much any type of traffic in the core because it doesn't really care what the traffic type is. It's not routing based on IP or some other layer three routing protocol. Instead, it's routing based on labels that are applied to your traffic as it enters the network. It's really a very cool technology.

Hope that helps,
John

 

[NetworksMD]

I remember when I first saw MPLS some carriers were offering services that classified the traffic and were charging more for higher priority traffic or charging additional rates for higher classified traffic based on volume. I think it still uses diffserv values in the calculation (or is it the TOS bit) to allow the end user to classify traffic.

I always thought the guarantee your traffic throughput sales pitch was an interesting angle since when selling frame relay some touted the fact that their core network was only 60 to 70 percent utilized at peak times.

I did like the way MPLS could mesh at L3 and create any to any connections.

 

[voltron1011]

MPLS also has the advantage of no distance costs... So if you have a multi-national company in numerous diff. countries, it usually pays to go MPLS.
My company has been wrestling with going MPLS for the last few years and we still haven't been able to justify it over our current frame-relay network. Of course we don't have voice or video and we have very specific routing needs that MPLS carriers can't deal with (yet).

 

[jneiberger]

Yeah, if you have a small f/r network, especially one that is doesn't have a lot of distance between your offices, MPLS might end up being more expensive. However, if you have a lot of distant offices MPLS can be a cost saver.

 

[burtsbees]

Thanks guys. I entered another post, sort of a question in response to this, but I guess it never went thru...
Could the technology be compared to CLNS technologies, like BGP, and the configurations? Like in BGP, you can maniplate attributes for a certain path to be preferred over another in certain cases, etc...is this kind of like MPLS? What exactly are the "tags"? Are they IP headers, or do they operate at different layers? Your responses have been very helpful, and I thank you all. Here's a star!

Burt

 

[jneiberger]

The labels are just a series of numbers significant only to the MPLS network. They are not IP headers, or any other layer three header. A route in MPLS is called a Forwarding Equivalance Class, which is simply any set of packets that follow the same routing rules. The label just differentiates between FECs.

Here's an FAQ from Cisco's site:

http://www.cisco.com/warp/public/105/mpls_faq_4649.shtml

 

[plshlpme]

Hey Burt.. did you get your head around this? I was jsut reading some old posts and thought ide give my 2 cents

basically when you order a service on our MPLS network your going to be given your own VRF..

every customer has their own VRF and the beauty of the vrf is that you can use whatever ip addressing you want and it wont affect other customers as each vrf is like your own private network.

so from a provider standpoint it is very scalable.

Typically the provider will put a managed device at your location and its called a CE.. Customer Edge..
your local access circuit will go back to the providers PE (you guessed it Provider Edge) router.

So again depending on the service but this connection will typically be running bgp. From that point the PE router will have a minimum of 2 trunks into the providers core network. the core is built up of many routers which we call P routers.. they have no customer connections and are purely labele switching routers (MPLS). They will be GSR routers at minimum and for us i saw somewhere that we are starting to put in the new CRS routers which are rediculous.

http://cisco.com/en/US/products/ps5763/index.html

so as mentioned above the beauty of this MPLS is that it is all QOS aware and so the qos models can be implemented from end to end. which is really critical these days to ensure the voice and video data streams are given the priority queuing they require all across the network.

A real benefit is also due to the design you can achieve total meshing of your sites by default without having to build pvcs between them.

The goal for the telcos is to get all legacy frame, atm etc customers cut over to the mpls backbone.

anywayslet me know if you have any other questions maybe i can answer.. but i think i forget your original question already

 

[burtsbees]

My question was really answered by everyone here. I was mainly wanting to experiment with some scenarios with my home lab, just to understand the technology. I am wanting to start my own business, and I want to know EVERYTHING. Ha ha. I only plan to be small scale, as I would target the rich doctors and lawyers who want to be eccentric with their equipment, and small businesses. One client (my only one) has a Canon copier that I do service on (I did that for 8 years), anhd he wants me to build his small network for his new building, including an FTP server. I am trying to learn and experiment with my own stuff, since there does not seem to be that great of a demand for networking (Cisco) people here in St. Louis.
My real question was really how Cisco equipment can be configured for MPLS stuff, and what the real advantage is of MPLS backbones over Cisco queueing techniques and QoS configurations. Thanks to all who have contributed thusfar. Who knows---maybe some of you guys can help me take over the world someday, like Pinky And The Brain. Ha ha. Thanks, guys. Also, I don't think there's enough talk in Tek-Tips about MPLS.

Burt

 

[norteldude78]

Burt,
I too am learning about mpls. i work for an ISP where they offer bgp/mpls vpn service, very cool stuff.

-B