MPLS Layer 3 VPN PE-CE OSPF

(Rene Molenaar) #1

This topic is to discuss the following lesson:

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Ospf domain id
(ALFREDO V) #2

Hi Rene,

I always wonder how different LOCATIONS but same customer will use the same area 0 but you just clarify this.
Well explain and I am having a lot of fun. I will be preparing for the CCIE written and just started with MPLS Fundamentals book.
Is there a test for the MPLS class?

Thanks

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(ALFREDO V) #3

Hi Rene,

I have seen some CE routers configure with this other statements and I was under the impression that we are just suppose to configure EBGP and redistribute OSPF but this CE has attributes that we configure on our example on the PE. Why? Are these extra statements on the CE that have no effect?. I removed the public ip address and the AS#.

router bgp 3000
address-family ipv4
  redistribute static
  redistribute ospf 25
  neighbor 1.1.1.1 activate
  neighbor 1.1.1.1 send-community
  neighbor 1.1.1.1 soft-reconfiguration inbound
  neighbor 1.1.1.1 remote-as 17
ip route 172.16.222.0 255.255.255.0 172.16.5.201
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(Rene Molenaar) #4

Hi Alfredo,

This config is from a CE router? It seems like the customer is running OSPF on their network but they use BGP to advertise their prefixes to the PE router (if 1.1.1.1 is the PE router). That’s not uncommon.

There used to be a MPLS exam in the CCIP track but it’s gone now.

Rene

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(Mario R) #5

Hi Rene,

I love the Configuration tabs at the bottom of the page. This and the videos really make your website interactive and fun. Would be great if they were found in each of your topics. But I know your website is always being updated for the best.

Thanks,

Mario

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(Rene Molenaar) #6

Hi Mario,

Thanks! I thought it would be a good idea to add these, makes it easy to try something yourself if you want.

From now on I’m also adding the capture files so anyone can see them, here’s an example:

https://www.cloudshark.org/captures/7441e9fb421e

Rene

 

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(ALFREDO V) #7

Hi Rene,

Can you please provide an example on how to configure redundancy? On your above example let’s suppose we have on left side CE-1 AND CE3 and on the right side CE-2. CE-1 and CE-3 are connected to the same data center, CE-2 connects through CE-1 but… CE-1 router connection goes down then I want to make sure that CE-2 router will reach the DATA CENTER going now through CE-3. How will you configure this scenario? I hope I make sense on my explanation.

 

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(Rene Molenaar) #8

Hi Alfredo,

I think I get the idea…kinda :slight_smile: Could you make a simple topology picture? I’ll see what I can do.

Rene

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(ALFREDO V) #9

OK I will start again:

Current connections are CE-2 users going to LONDON-DATA CENTER though CE-1, CE-3 is up and running, LONDON DATA CENTER and ITALY-BRANCH are connected using a 100meg point to point connection and running protocol OSPF then suddenly there is an storm and CE-1 connection to the PE-1 goes down so in order for CE-2 users to continue connecting to the DATA CENTER will need to go through CE-3–>ITALY-BRANCH–>LONDON-DATA CENTER.

How do you configure redundancy? I suppose the configuration is done on the PE-1 but what is the configuration. I hope I make sense this time.

Please advise

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(ALFREDO V) #10

This is the diagram

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(ALFREDO V) #11

This is a JPEG

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(ALFREDO V) #12

Hi Rene,

I am trying to attach the file as a JPEG but I don’t see it anywhere.

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(Rene Molenaar) #13

Hi Alfredo,

Can you upload the image through http://postimage.org/ and then add it here?

Uploading images on the forum is currently disabled.

Rene

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(ALFREDO V) #14

I uploaded the image.

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(Rene Molenaar) #15

Hmm I don’t see a link here? :slight_smile:

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(ALFREDO V) #16

Here is finally. Sorry

http://postimg.org/image/5jrskzaql/

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(Rene Molenaar) #17

Hi Alfredo,

What do you use between the PE/CE routers? Also OSPF? Should the london and italy sites always use their direct 100M link or is this only used as a backup?

Rene

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(ALFREDO V) #18

Hi Rene,

What do you use between the PE/CE routers? I am using eBGP
Should the london and italy sites always use their direct 100M link or is this only used as a backup? Yes that should be on so Italy site can reach the DATACENTER located in London.

 

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(Rene Molenaar) #19

Hi Alfredo,

Are your London and Italy sites only advertising their own prefixes?

If you want your users from CE2 to be able to reach London in case CE-1 is down then you should advertise the prefixes from London from OSPF into BGP on Italy so that CE3 can learn them. You could use conditional advertising or use some of the BGP attributes so that this path is not preferred as long as CE-1 is up and running.

Rene

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(Davis W) #20

Hi Rene,

I tried to redistributed the route into the OSPF in CE1 router, and the PE1 did received the route as E2 route. But the other PE2 not received the VPNV4 route from PE1 and also can not advertised it to CE2. Any idea how to fix this?

Davis

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