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 with send-label and redistribute the loopbacks from both AS in OSPF. (more&hell...

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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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In my back to the basis ... The frame relay switching ... Not much used nowadays but still in the CCIE! Frame relay switching is very straightforward, first you need to enable frame relay switching globally (more…)

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Sometimes it can be useful to set up a MPLS Traffic Engineering tunnel between sites, but did you ever notice that by default the IGP will not consider those tunnels for traffic ? Did you ever try to change the OSPF cost of tunnel to force it to take traffic ? And it didn't work right ? Lets check that. We have a 7 routers setup, R1 and R7 will never be able to run MPLS Traffic Engineering they'll just be plain MPLS/OSPF. I changed the cost ...

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... otherwise you could look stupid :)

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Backuping Flickr

Posted on April 5, 2010

I have over 2,000 pictures on Flickr as I used to upload all my pics there. But now I'd like to keep only my best shots over there and keep the familly and other stuff on another private website. I certainly have a backup of them somewhere but how can I be sure ? As I don't want to take any risk such as loosing pictures I wanted to bring them all back on my laptop... And preferably not one by one ... I found a great tool called Migratr (http:...

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We saw in a previous post how to set up a basic MPLS Traffic Engineering tunnel, we used explicit and dynamic path which worked very well but explicit path don't scale well and dynamic is too hazardous (you don't really know where your traffic goes). Hopefully for us the MPLS Traffic Engineering guys thought about it and added a function called MPLS Traffic Engineering Affinity. I'll be using the same setup as for MPLS traffic engineering ...

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BGP has a feature called BGP conditional advertisement, the idea of this feature is to have the capability to announce a prefix on specific conditions. Lets say for example that you are dual homed, but you only want to use a provider in last resort (very expensive for example). You can decide to announce your prefixes to the expensive ISP only when the other one is down. I used the following topology in dynamips. For this example I preconf...

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When configuring ISIS on an interface (a loopback for example) you something find the constraint "Advertise the Loopback0 in ISIS, do not use ip router isis and the prefixes should appear as internal ISIS routes". Lets take in another way, ever wondered why ip router isis disappears when you type passive-interface ? (more…)

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When configuring ISIS over NBMA networks (such as ATM or FR) don't forget that you probably configured static mapping such as For ATM (more…)

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