I do not foresee any problems, maybe others do? I just find the design guideline below too strict. In small networks there may be only one OSPF area, but larger networks typically have more areas. Connections to the Internet or to other external networks like corporate networks, tend to be on routers in the edge/distribution layer of the network. Those routers are in OSPF areas different to zero (al least in the OSPF designs I have seen so far).
Also Cisco advises to connect 'the Internet' in the distribution layer (in the DCN and CID courses). So for example for designs where three or four core routers are fully meshed in OSPF area 0, and the surrounding distribution layer devices belong the area x, with x/=0, the ASBR will not be connected to area 0. I also noticed a similar question in the thread called "OSPF to Internet". Eric Brouwers ----- Original Message ----- From: To: "ericbrouwers" Sent: Thursday, January 23, 2003 6:05 PM Subject: Re: ASBR in backbone area?? [7:61614] > > What kind of problem do you see putting the ASBR on the backbone area? > > Just to think about. > > > > > > "ericbrouwers" @groupstudy.com em 22/01/2003 > 18:45:17 > > Favor responder a "ericbrouwers" > > Enviado Por: [EMAIL PROTECTED] > > > Para: [EMAIL PROTECTED] > cc: > > Assunto: ASBR in backbone area?? [7:61614] > > > Hi there, > > Cisco Press' CCNP Routing Exam Certification Guide advises to place an ASBR > in > the backbone area (p. 290, chapter 6): > > "... If there is any redistribution between other protocols to OSPF on a > router, it will be an ASBR. Although you can place this router anywhere in > the > OSPF hierarchical design, it should reside in the backbone area. Because > any > traffic leaving the OSPF domain will also likely leave the router's area, > it > makes sense to place the ASBR in a central location that all traffic > leaving > its area must traverse..." > > I find this a strange design guideline. I would rather prefer to connect an > external network to the edge/distribution layer in an OSPF area different > to > the backbone area. As a consequence redistribution would happen outside the > backbone area... > > What's your view on this? > > Eric Brouwers Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=61980&t=61614 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
