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BGP send-label in Inter AS scenarios

When playing with the MPLS Inter AS options I was obliged to use the neighbor x.x.x.x send-label command to exchange my label information between to AS. the interesting thing is that depending on how I was send the PE loopbacks in BGP I could loose connectivity between CEs. Lets play around with the send-label command to see how it really works. I built a 6 router ...

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CEF and VRF

A think you may want to know and that I discovered when playing on a device is that VRF needs CEF (ok that's not new) and actually it won't let you do it. The tricky thing is that if you create a VRF without CEF on older version of IOS you don't get this and when you enable CEF AFTER having configured the VRF it won't work. You'll have to reboot the router for the ...

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ISIS redistribution from L2 to L1

As you know there are 2 types of levels in ISIS Level 1 and level 2. A router can be in one of these 2 types of level or can be a L1/L2 router (kind of ABR). A router L1/L2 set an ATT bit to indicate to routers in L1 a default gateway, whereas a L2 router will have all the more specific route. In some case you'd like to have all (or a subset) of the L2 routes in L1. ...

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Basic AToM configuration

Same as for L2TPv3 we'll go over the basic configuration of an AToM tunnel. In this example we'll only do ethernet to ethernet. We'll go in internetworking in another post. As for L2TPv3 we'll use the CsC configuration to setup our tunnels between R1 and R8 To manage this interconnection we’ll be using the interface G1/0 of R2 and G2/0 of R7. (more…)

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Basic L2TPv3 configuration

L2TPv3 in a L2VPN technology, we're going to have quick look on how to configure it. For this example I'll be using the CsC topology to interconnected R1 and R8 To manage this interconnection we'll be using the interface G1/0 of R2 and G2/0 of R7. (more…)

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MPLS VPN Carrier Supporting Carrier: The BGP way

As usual when you study CCIE you need to know at least 2 ways to do everything, same for Carrier supporting Carrier (CsC). I know that InterNetwork Expert they say that the chances are slim to have MPLS VPN Carrier supporting Carrier but you never know, it's not the biggest bit of study anyway. MPLS VPN Carrier supporting Carrier Lab Topology So for our setup ...

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Using next-hop-unchanged

After the next-hop-self time to talk about next-hop-unchanged. I couldn't figure out the real life usage of this before I labbed it. In this setup I'll use my interAS topology R1 and R5 will be our route reflectors, they'll be peering through eBGP multihop only for address family vpvn4. R2 and R4 will be our ASBRs they'll peer through eBGP on address family ipv4 ...

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Impact of next-hop-self in BGP

As you know in BGP the next hop will only be changed for eBGP neighbors, iBGP will not change the next hop. The "problem" is that if you didn't advertise in the IGP the link between the eBGP neighbors you'll run into an issue. I built a 6 router topology that will be used for inter-AS MPLS so we'll just use a few routers for the eBGP. (more…)

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Configuring PPPoE

For my CCIE prep when doing the IE workbooks I had to configure PPPoE with "MD5 authentication" Server side (the old way, we'll see that in details after): (more…)

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