Neil, Did you read blog articles on this subject I wrote some months ago?
-- Marko Milivojevic - CCIE #18427 Senior Technical Instructor - IPexpert FREE CCIE training: http://bit.ly/vLecture Mailto: [email protected] Telephone: +1.810.326.1444 Web: http://www.ipexpert.com/ On Wed, Jan 19, 2011 at 15:18, O'Brien, Neil <[email protected]> wrote: > Hi Guys, > > > > I'm labbing up some OSPF LSA scenarios and I think I've confused myself > more than anything else but would appreciate some clarification. > > > > LSA Type 1 - Sent from all OSPF Routers in an Area, advertising the > links/networks it has. > > LSA Type 2 - Sent from DR to all OSPF routers telling everyone who's in > it's area. > > > > So within an LSA Type 1 packet, amongst everything else, there's the > Link State ID which appears to be the RID, there's the ADV Router which > appears to be the RID and then the types of networks it has -stub, > transit and their subnets. There's nothing that I can see that says > "This is the actual IP you can reach me at" > > > > In an LSA Type 2, it seems to just contain the RID's of all other OSPF > routers on the segment. > > > > The issues I seem to have is how does the SPF algorithm derive the next > hop for a network. The packet captures I've taken for LSA Types 1 & 2 > all deal in RID. > > > > Does it take it from the neighbour table which does contain actual > interface ip of its neighbour?? > > > > When I debug ospf spf, I see where it installs the route with the next > hop but I'm not sure where it actually gets the next hop info. > > > > Thanks in advance, > > Neil > > > > > > > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
