fun with bi-directional forwarding (BFD)

So I was tasked to provide a failover mechanism for a customer with Juniper equipment without using OSPF.

With the L2 providers we use there is always a link from the CPE to the provider equipment and then it breaks out to their backbone.  Now, this means that there could be a break in the provider network and the customer CPE would still see the link as up.  We would then be blindly forwarding traffic into a black hole. Continue reading

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Juniper as-path-expand with bgp communities

With working in an ISP enviroment I always find myself trying to automate or create process for others to follow so I don’t have to do the work 😉

I recently started to look at BGP communities and to see how I can apply them in day to day life.  One of the applications that would make my life easier the bigger we grow is putting the onus onto the bgp transit customer to affect how we advertise/announce them to our upstreams, peers and customers. Continue reading

How to recover Cisco IOS from rommon

Thought I would add this to my blog to help anyone that was in the same situation I had back in April.  A big thanks to Richard Morrell ( @richardmorrell ) for this!

If you have a Cisco router which is unable to boot it’s IOS (flash image is corrupted, lost or wrong build), then you can boot the rommon and ask it to TFTP a replacement image across.  It is preferable you have a working flash device in the router to save the flash image to, but you can just boot it straight from TFTP to memory if you’re desparate.  Pre-requesits: Continue reading