MPLS noobie - need assistance

Answered Question
Feb 19th, 2009

Hello all!!!


I have been tasked with getting our company rolled into MPLS.

We are currently an OSPF shop. We have all remote sites on point-to-point T1s off a DS3.

If anyone can provide me any tips I would greatly appreciate it.

I have no experience in this area. Currently studying for BSCI.


Where should I direct my research?

What should I be planning? What should I be asking vendors, etc. Is BGP the way to go?


All of your expertise would be a great help.

Thanks so much!!!


George

Correct Answer by Giuseppe Larosa about 8 years 1 week ago

Hello George,


L3 VPN services can use OSPF as the PE-CE protocols and this has low impact and doesn't require to use BGP on your side.

the provider can carry OSPF routes between sites as O inter-area routes.


a L2 transport services over MPLS allow you to build directly OSPF adjacencies with your own routers.


Some providers can charge more for a L3 VPN service using OSPF as PE-Ce rouoting protocol.


the MPLS service will be on the SP side


Hope to help

Giuseppe


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Paolo Bevilacqua Thu, 02/19/2009 - 11:00

Hi, when you're a customer of MPLS service, you do not see it and do not need to know how it really works inside.


Ask your SP to give you ethernet-like links, and run normal OSPF on it.


If SP says that they cannot and insist you have to use BGP, either OK that, or look for another SP.

gdiazjr03 Thu, 02/19/2009 - 12:56

Thanks for your answer.

With Ethernet-like links do you mean just handoff? I wouldn't want to have to worry about VTP and same broadcast domain. Does that make sense?

Mohamed Sobair Thu, 02/19/2009 - 11:33

Hi,


MPLS provide a VPN service by emulating the dedicated point to point links.


you have 2 options:


either you go for (Overlay Model) or (Peer to peer model).


The Overlay Model is basically binds your layer-2 circuit and doesnt participate in the routing but this harder to provision besides Scalability the advantage is more Secure but not scalable.


The Peer to peer Model provides more control by participating in the layer-3 routing and easier to provision and more Scalable.


Since your Sites are connected via dedicated (Point to point) Links, I would recommend you for Peer to peer model, By using this model, you can replace those point to point links to reduce cost and gain better control of the traffic, You can also provision the links easily.


You should direct your research about the Technology it self first, why MPLS? and what benefit I would have? what is required interms of hardware and software at last...


About the vendors, The mainly 2 Vendors in the Market nowadays are (Juniper & Cisco) , having your budget calculated , besides the facilities you are going to get from each vendor includin performance should be in plann. But its not Only price, there is a lot of items should be taken into consideration.


Regarding the BGP, You will lastly find BGP is necessary to carry the VPNv4 or the Labeled VPNv6 prefixes beides Multicast.


The MP-BGP is designed to carry additional information in its BGP update includes (RT Extended Communities) + (Labeled VPNv4 Routes) + (Labeled VPNv6 routes) + (Multicasdt MDT default , Mdt data ) MDT SAFI=128 and MDT AFI=1 . Thats why its a must.


Hope I am informative,

Mohamed

gdiazjr03 Thu, 02/19/2009 - 12:58

Thank you for your answer.

I will take all into consideration. If I have to I would like the carrier to handle the BGP side of things. What would be the pro/cons from your experience?

Correct Answer
Giuseppe Larosa Thu, 02/19/2009 - 13:14

Hello George,


L3 VPN services can use OSPF as the PE-CE protocols and this has low impact and doesn't require to use BGP on your side.

the provider can carry OSPF routes between sites as O inter-area routes.


a L2 transport services over MPLS allow you to build directly OSPF adjacencies with your own routers.


Some providers can charge more for a L3 VPN service using OSPF as PE-Ce rouoting protocol.


the MPLS service will be on the SP side


Hope to help

Giuseppe


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