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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: The Size of OSPF Network
On Fri, 31 Mar 2000, HANSEN CHAN wrote: > > Dear all, > > For the big ISP networks (tier 1 or 2) that happens to use OSPF, what is > the typical number of OSPF areas in the network? According to OSPF > books, a typical area is consisted of 200 routers. Are those guidelines > ever followed in real ISP network deployment? > > Any input is highly appreciated. In an ISP context, given that IS-IS and OSPF are roughly equivalent in terms of resource consumption on a theoretical level (individual implementations may vary depending on the various data structures, algorithms used etc. for costing models), I see no problem with running 300-400 routers in a area. Of course this depends on how stable you expect the underlying transport fabric to be and what you use OSPF for (e.g. ibgp-hack) and how smart you are when you go about it (i.e. a well designed IGP structure may have 500-700 routers in one area and not have significant issues). For an enterprise type network with OSPF as the sole protocol and depending on the number of adjacencies, your mileage may vary considerably. /vijay
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