From: Mohammad Saeed (mzsaeed@gmail.com)
Date: Tue May 22 2007 - 13:13:01 ART
Although the route is IA, as Angelo said, routes through Area 0 are
preferred over route through normal area.
Mohammad Zahed Saeed
> On 5/22/07, Eric Poulin <epoulins@yahoo.com> wrote:
> > I understand that intra-area routes are preferred over inter-area routes, and inter-area
> > routes are preferred over external-routes, but the route coming from R4 on both links is
> > an inter-area route. Unless OSPF prefers "advertising router" within Area0 over Area45, I
> > don't see why R5 prefers the Frame Relay link with a higher cost.
> >
> >
> > --- "Huizinga, Rene" <rhuizinga@upcbroadband.com> wrote:
> >
> > > I believe this comes down to the intra-area over inter-area rule in OSPF.
> > > If I understand the description correctly from this email, the remote
> > > router-id may play a role in here. Since that's in Area0, it may be the
> > > tie-breaker in this. If this is this tie-breaker, then intra- over
> > > inter-area, regardless of cost et all !
> > >
> > > Cya
> > >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Eric
> > > Poulin
> > > Sent: Tuesday, May 22, 2007 4:42 PM
> > > To: M S; ccielab@groupstudy.com
> > > Subject: RE: Question about OSPF preferring higher cost route from area0
> > > over lower cost from another area?
> > >
> > > Here's the output:
> > >
> > > Rack1R5#sh run | beg router ospf
> > > router ospf 1
> > > router-id 150.1.5.5
> > > log-adjacency-changes
> > > network 150.1.5.5 0.0.0.0 area 0
> > > network 183.1.0.5 0.0.0.0 area 0
> > > network 183.1.45.5 0.0.0.0 area 45
> > >
> > >
> > > --- M S <michaelgstout@hotmail.com> wrote:
> > >
> > >
> > > ---------------------------------
> > >
> > > I would like to see the "show run | b router ospf" output.
> > >
> > > Thank you.
> > >
> > >
> > >
> > >
> > > ---------------------------------
> > >
> > > From: Eric Poulin <epoulins@yahoo.com>
> > > Reply-To: Eric Poulin <epoulins@yahoo.com>
> > > To: ccielab@groupstudy.com
> > > Subject: Question about OSPF preferring higher cost route from area0 over
> > > lower cost from another area?
> > > Date: Mon, 21 May 2007 21:04:27 -0700 (PDT) Hi GS,
> > >
> > > I have two routers, R4 and R5, running OSPF between each other over Frame
> > > Relay (Area0) and also Ethernet (Area45). R5 is learning an inter-area route
> > > 150.1.6.6/32 from R4 over both links. The OSPF cost to reach R4 over the FR
> > > is 64 and Ethernet is 1. Please can someone explain me why R5 prefers the
> > > route over the frame Relay as opposed to the Ethernet? I was expecting R5 to
> > > chose its Ethernet link with a cumulative cost of 3 instead of the FR
> > > interface with a cumulative cost of 66? Are routes for the same prefix
> > > preferred within Area0?
> > >
> > > Thanks for your help,
> > > Eric
> > >
> > > ----------------------------
> > > Rack1R5#sh ip ospf neighbor
> > > Neighbor ID Pri State Dead Time Address Interface
> > > 150.1.4.4 0 FULL/DROTHER 868 msec 183.1.0.4 Serial0/0
> > > 150.1.4.4 1 FULL/DR 00:01:46 183.1.45.4
> > > FastEthernet0/1
> > > ----------------------------
> > > Rack1R5#sh ip route ospf
> > > 150.1.0.0/16 is variably subnetted, 9 subnets, 2 masks
> > > O IA 150.1.6.6/32 [110/66] via 183.1.0.4, 00:05:09, Serial0/0
> > > ----------------------------
> > > Rack1R5#sh ip ospf database summ 150.1.6.6
> > >
> > > OSPF Router with ID (150.1.5.5) (Process ID 1)
> > >
> > > Summary Net Link States (Area 0)
> > >
> > > Routing Bit Set on this LSA
> > > LS age: 1865
> > > Options: (No TOS-capability, DC, Upward)
> > > LS Type: Summary Links(Network)
> > > Link State ID: 150.1.6.6 (summary Network Number)
> > > Advertising Router: 150.1.4.4
> > > LS Seq Number: 80000012
> > > Checksum: 0xC323
> > > Length: 28
> > > Network Mask: /32
> > > TOS: 0 Metric: 2
> > >
> > >
> > > Summary Net Link States (Area 45)
> > >
> > > LS age: 1865
> > > Options: (No TOS-capability, DC, Upward)
> > > LS Type: Summary Links(Network)
> > > Link State ID: 150.1.6.6 (summary Network Number)
> > > Advertising Router: 150.1.4.4
> > > LS Seq Number: 80000012
> > > Checksum: 0xC323
> > > Length: 28
> > > Network Mask: /32
> > > TOS: 0 Metric: 2
> > > ----------------------------
> > > Rack1R5#sh ip ospf database router 150.1.4.4
> > >
> > > OSPF Router with ID (150.1.5.5) (Process ID 1)
> > >
> > > Router Link States (Area 0)
> > >
> > > Routing Bit Set on this LSA
> > > LS age: 186
> > > Options: (No TOS-capability, DC)
> > > LS Type: Router Links
> > > Link State ID: 150.1.4.4
> > > Advertising Router: 150.1.4.4
> > > LS Seq Number: 80000018
> > > Checksum: 0x8AE6
> > > Length: 48
> > > Area Border Router
> > > Number of Links: 2
> > >
> > > Link connected to: a Transit Network
> > > (Link ID) Designated Router address: 183.1.0.5
> > > (Link Data) Router Interface address: 183.1.0.4
> > > Number of TOS metrics: 0
> > > TOS 0 Metrics: 64
> > >
> > > Link connected to: a Stub Network
> > > (Link ID) Network/subnet number: 150.1.4.4
> > > (Link Data) Network Mask: 255.255.255.255
> > > Number of TOS metrics: 0
> > > TOS 0 Metrics: 1
> > >
> > >
> > >
> > > Router Link States (Area 45)
> > >
> > > Routing Bit Set on this LSA
> > > LS age: 576
> > > Options: (No TOS-capability, DC)
> > > LS Type: Router Links
> > > Link State ID: 150.1.4.4
> > > Advertising Router: 150.1.4.4
> > > LS Seq Number: 8000001C
> > > Checksum: 0x6C97
> > > Length: 36
> > > Area Border Router
> > > Number of Links: 1
> > >
> > > Link connected to: a Transit Network
> > > (Link ID) Designated Router address: 183.1.45.4
> > > (Link Data) Router Interface address: 183.1.45.4
> > > Number of TOS metrics: 0
> > > TOS 0 Metrics: 1
> > > ----------------------------
> > >
> > >
> > >
> > > ____________________________________________________________________________
> > > ________Take
> > > the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news,
> > > photos & more.
> > > http://mobile.yahoo.com/go?refer=1GNXIC
> > >
> > > _______________________________________________________________________
> > > Subscription information may be found at:
> > > http://www.groupstudy.com/list/CCIELab.html
> > >
> > >
> > >
> > > ---------------------------------
> > > More photos, more messages, more storage get 2GB with Windows Live Hotmail.
> > >
> > >
> > >
> > >
> > >
> > > ____________________________________________________________________________
> > > ________Pinpoint customers who are looking for what you sell.
> > > http://searchmarketing.yahoo.com/
> > >
> > > _______________________________________________________________________
> > > Subscription information may be found at:
> > > http://www.groupstudy.com/list/CCIELab.html
> > >
> >
> >
> >
> >
> > ____________________________________________________________________________________Looking for a deal? Find great prices on flights and hotels with Yahoo! FareChase.
> > http://farechase.yahoo.com/
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Fri Jun 01 2007 - 06:55:21 ART