The auto-cost capability in some vendors devices seems to have left many people ignoring the link metrics within their IGP. From what I recall in the standards - bandwidth is one possible link metric but certainly not the only one. Network designers are free (and I would encourage to) pick whatever metric is relevant to them. On 24/01/2014 22:26, Erik Sundberg wrote:
I am looking for a formula that other people are using .p
I've started to use a combination of 3 metrics to determine my costing: * The traditional auto-cost calculation based on a 100Gbps reference which gives far more useful values than the old 100Mbps reference. * An average or nominal link latency multiplied by a factor of 200. Sometimes adjusted if I want two geographically diverse paths between the same endpoints to have equivalent costs. * Path length in km multiplied by 2. This accounts for situations when the nominal latency is too small to accurately determine and assumes 1 ms per 100 km. I then pick the largest of the above 3 metrics as my OSPF cost. -- Graham Beneke