Hi Priscilla, The use of the "ip ospf network point-to-point" as a mechanism to enable one to advertise the loopback address as a subnet route is from Doyle (Routing TCP/IP V1), page 417, footnote 9.
Priscilla Oppenheimer wrote: > > At 08:59 AM 3/4/02, bergenpeak wrote: > >1) A loopback address is normally advertised by OSPF as a host route. > >The command "ip ospf network point-to-point" enables one to specify > >that the interface should be advertised as a subnet route. What are > >the benefits for doing this? > > I can't imagine any benefits. Where did you find this info?? > > I do see some mention in RFC 2328 of using a host versus a subnet for the > Link ID. "On point-to-point networks, if the neighbor's IP address is > known, set the Link ID of the Type 3 link to the neighbor's IP address, and > the Link Data > to the mask 0xffffffff (indicating a host route).... If a subnet has been > assigned to the point-to-point link, set the Link ID of the Type 3 link to > the subnet's IP address, and the Link Data to the subnet's mask..." > > >2) Must a link cost be the same on for all routers that share the > >link? Is there a protocol reason for this? Some other reason? > > I couldn't find anything in RFC 2328 that says that two routers connected > to a link MUST agree on the cost. The RFC writers use the term MUST > carefully. If it were required, they would put it in the RFC. > > I think it would be a good idea to make them agree, though.... > > >3) In the Exstart phase, how is the master selected? Chappel's > >book says RID while Doyle's say highest interface IP address. Which > >is it? > > The router with the higher Router ID becomes the master. > > >4) I'm somewhat unclear on the Exchange and the Loading states. When > >a router goes into Exchange state, does it send all DDPs it knows > >about before processing any DDPs received from other adjancent > >neighbors? > > I think so, but I've never thought about the database synchronization > issues associated with a router that is a neighbor to many routers. My > guess is that it can only be in the exchange state with one router at a > time. Otherwise it would be exchanging database info with one router as the > info was being updated by another router?? > > >Thus, a router goes into Exchange state, sends all DDPs it knows about, > >then goes into Loading state, where it issues LSRs for LSAs it wants > >more > >details on? Is this the process? > > Sounds right. See the RFC for the details. > > >5) Is there a difference between DBD and DDP packets? > > I would avoid the term DDP, since it means Datagram Delivery Protocol to > AppleTalk people. ;-) > > >Thanks > ________________________ > > Priscilla Oppenheimer > http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=37255&t=37142 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
