OSPF and Summarization

[chrisayres]

I have looked on CCO and in various Cisco books and I can't find a straight answer to this question

Does an OSPF ABR summarize contiguous routes by default or is the "area range" command required

[Georg Pauwen]

Hello,

no, the ABR does not do any summarization by default. The only thing it does ´by default, at least post-IOS 12.1(6), is to add a route to Null0 for the area range summary route, in order to prevent routing loops...

HTH,

GP