Right, but if you specify a network of 150.20.255.255/32 the other neighbor cannot be contained in this range. That's what's being done here in this assignment. It just says: network 150.50.25.2 0.0.0.0 area 0 and that ip is of the local router, not the remote peer, so it's just advertising it's own local peer network /32?
I always thought of network statements as advertising out networks, (i.e. these belong to me because i have links in these networks), i never linked them directly to setting up adjacencies. Regards Alef On Jun 24, 2011, at 3:37 PM, Matlock, Kenneth L wrote: > Sorry, knew I should have waited before I had more caffeine before > emailing :) > > Ok, from the top. On Cisco boxes, the 'network' statement under the > routing protocol does 2 things. > > 1) Allows neighbor establishment with neighbors in that netblock > 2) Allows that routing protocol to inject routes it knows about > (external to the routing process), into the topology table for that > routing process. > > So let's say you have under your 'router ospf 1' process > 'network 150.20.0.0' > > That will mean that the router will establish adjacencies with neighbors > in the 150.20.x.x range, and will inject by default any > locally-connected interfaces it has, as long as they're contained within > the 150.20.x.x range. > > So if the router has 4 interfaces. > 150.20.1.1/24 > 150.20.200.1/30 > 150.20.255.255/32 > 151.20.1.1/24 > > The routing process will establish adjacencies with neighbors on the > first 3 interfaces, and will inject those first 3 interface networks > into the topology table for the routing process. > > It will not however inject the last one because it's not contained > within the 150.20.0.0/16 netblock you have as a network statement. > > Ken Matlock > Network Analyst > Exempla Healthcare > (303) 467-4671 > [email protected] > > > > -----Original Message----- > From: Alef [mailto:[email protected]] > Sent: Friday, June 24, 2011 8:24 AM > To: Matlock, Kenneth L > Cc: [email protected] > Subject: Re: [OSL | CCIE_RS] vol1 27.2 why are the links in OSPF not > advertisedas in EIGRP > > So you're saying when we have network > > a /27 and network b /26 and network c /24 > > it would be ok to just advertise in the 32 host routes /p2p links and > the networks would still be known without explicitly advertising them in > (As in say ospf?) > On Jun 24, 2011, at 1:37 PM, Matlock, Kenneth L wrote: > >> Maybe I misinterpreted the question, but het, that's never stopped me > before :) >> >> The 'network' statement on the routing protocol doesn't necessarily > specify the EXACT netblock to announce. >> >> The 'network' statement merely gives you what range of netblocks to > announce, or establish neighbor adjacencies on. So a 'network > 150.50.25.2' statement says to establish neighbor adjacencies with > anything 150.50.0.0 range (150.x.x.x is in the class 'B' range, so by > default has a /16 netmask unless you tell it different), and announce > any connected interfaces that are in the 150.50.0.0/16 range. >> >> Personally in production I purposely restrict down the network > statements to the smallest possible, but that's only so I know it's a > 100% conscious decision that I'm injecting a route into the production > route tables :) >> >> Make sense? >> Ken >> >> ________________________________ >> >> From: [email protected] on behalf of Alef >> Sent: Fri 6/24/2011 4:36 AM >> To: [email protected] IE >> Subject: [OSL | CCIE_RS] vol1 27.2 why are the links in OSPF not > advertisedas in EIGRP >> >> >> >> In this task, the the assignment seems the same (apart from the > configure the network statements to include the network mask) but the > link is advertised as: >> >> network 150.50.25.2 >> >> and not as 150.50.25.0 0.0.0.3 or 0.0.0.1 >> >> in 27.1 eigrp does advertise as a /30, 0.0.0.3 >> >> is it not best practice to always advertise the networks into any > routing protocol properly ? >> >> Alef >> _______________________________________________ >> For more information regarding industry leading CCIE Lab training, > please visit www.ipexpert.com >> >> Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com >> >> >> *** Exempla Confidentiality Notice *** The information contained in > this message may be privileged and confidential and protected from > disclosure. If the reader of this message is not the intended recipient, > or an employee or agent responsible for delivering this message to the > intended recipient, you are hereby notified that any other > dissemination, distribution or copying of this communication is strictly > prohibited. If you have received this communication in error, please > notify me immediately by replying to the message and deleting it from > your computer. Thank you. *** Exempla Confidentiality Notice *** >> > > *** Exempla Confidentiality Notice *** The information contained in this > message may be privileged and confidential and protected from disclosure. If > the reader of this message is not the intended recipient, or an employee or > agent responsible for delivering this message to the intended recipient, you > are hereby notified that any other dissemination, distribution or copying of > this communication is strictly prohibited. If you have received this > communication in error, please notify me immediately by replying to the > message and deleting it from your computer. Thank you. *** Exempla > Confidentiality Notice *** > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com
