From: Connary, Julie Ann (jconnary@xxxxxxxxx)
Date: Fri May 04 2001 - 10:31:23 GMT-3
Sanjeewa
Right now it is 0.0.0.255 on both R2 and R5.
After I changed it so that it is 0.0.0.0 (i.e network 137.20.20.2 0.0.0.0
area 0) the results are:
That this totally changes the behavior of how the external links are
advertised and what forward address is used.
Now my ip ospf database external 0.0.0.0 looks like:
r5#show ip ospf database external 0.0.0.0
OSPF Router with ID (172.168.200.1) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 70
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 200.200.200.1
LS Seq Number: 80000001
Checksum: 0x9D27
Length: 36
Network Mask: /0
Metric Type: 1 (Comparable directly to link state metric)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 1
Why does that make a difference? I thought that the inverse mask on the
network statement only decided which interfaces to run OSPF on - now here
we are seeing it is having an effect on how external routes are advertised.
Any pointers to documentation on this?
Julie Ann
At 11:11 PM 5/4/2001 +1000, you wrote:
>Julie
>How is your OSPF inverse mask 0.0.0.(255-mask) or 0.0.0.0
>Just try and let me know :)
>Rgds
>Sanjeewa
>
>-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
>Connary, Julie Ann
>Sent: Friday, 4 May 2001 9:10 PM
>To: Mas Kato
>Cc: ccielab@groupstudy.com
>Subject: RE: originating an ospf default route
>
>
>Mas,
>
>I just realized that the lab used 137.20.20.1 on r2 and 137.20.20.2 on the
>defualt route - I used
>137.20.20.2 on r2 and 137.20.20.3 as the next hop for the default route.
>
>So that was my bad - but the question still applies - another person
>suggested no icmp redirect.
>
>Julie ann
>
>At 06:55 PM 5/3/2001 -0700, you wrote:
> >Julie Ann,
> >
> >I haven't done that lab yet, but after a quick glance, I'm a little
> >confused trying to reconcile what Task One, step 1 says (great start,
> >eh?), what Task One, step 4 says and the addressing you're using.
> >
> >But it sounds like the bottom-line is the solution specifies that the
> >advertised next-hop is r2's own Ethernet and not the next-hop configured
> >in r2's static route? Could it be a typo? Because it looks like the
> >forwarding address is working as it should, so to force the solution it
> >needs to be zeroed out...
> >
> >I found this on CCO: http://www.cisco.com/warp/customer/104/10.html
> >
> >What if you change the OSPF network type on r2's and r5's Ethernets to
> >point-to-multipoint?
> >
> >Regards,
> >
> >Mas Kato
> >
> >
> >-----Original Message-----
> >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> >Connary, Julie Ann
> >Sent: Thursday, May 03, 2001 5:12 PM
> >To: ccielab@groupstudy.com
> >Subject: originating an ospf default route
> >
> >
> >Hi,
> >
> >working a lab that has the following:
> >
> >
> >r2------ethernet ---r5-----
> >
> >r2's e0 = 137.20.20.2
> >r5's e0 = 137.20.20.10
> >r2 has an ip route 0.0.0.0 0.0.0.0 137.20.20.3 (another router on the
> >ethernet.)
> >r2 has an ip ospf default information-originate always metric-type 1
> >statement.
> >
> >r5 sees this default route as:
> >
> >O*E1 0.0.0.0/0 [110/21] via 137.20.20.3, 00:01:40, Ethernet0
> >
> >this is ccbootcamp lab 5. However - in the routing tables provided R5
> >should
> >see this as
> >
> >O*E1 0.0.0.0/0 [110/21] via 137.20.20.2, 00:02:40, Ethernet0
> >
> >If I look at the database I see:
> >
> >OSPF Router with ID (172.168.200.1) (Process ID 1)
> >
> >
> > Type-5 AS External Link States
> >
> > Routing Bit Set on this LSA
> > LS age: 143
> > Options: (No TOS-capability, DC)
> > LS Type: AS External Link
> > Link State ID: 0.0.0.0 (External Network Number )
> > Advertising Router: 200.200.200.1
> > LS Seq Number: 80000006
> > Checksum: 0x9C6E
> > Length: 36
> > Network Mask: /0
> > Metric Type: 1 (Comparable directly to link state metric)
> > TOS: 0
> > Metric: 20
> > Forward Address: 137.20.20.3
> > External Route Tag: 1
> >
> >So my question is - how in the answers does the forwarding address
> >become
> >router 2 (137.20.20.2) and not 137.20.20.3?
> >Is there a trick to this that I am missing? Or should OSPF when it
> >originates a default route within the same area not change the
> >forwarding address?
> >
> >Thanks,
> >
> >Julie Ann
> >
> >p.s. I also got the ospf-demand circuit to work in 5b by making sure
> >that
> >my ISDN interface was not being redistributed
> >back into ospf from igrp and having LSA type 5's keep the circuit up.
> >The
> >lab says that ospf demand circuit does not
> >work for this topology - but mine worked fine.
> >
> >------------------------------------------------------------------------
> > Julie Ann Connary
> > | | Network Consulting Engineer
> > ||| ||| Federal Support Program
> > .|||||. .|||||. 13635 Dulles Technology
> >Drive,
> >Herndon VA 20171
> > .:|||||||||:.:|||||||||:. Pager: 1-888-642-0551
> > c i s c o S y s t e m s Email: jconnary@cisco.com
> >
> >------------------------------------------------------------------------
> >**Please read:http://www.groupstudy.com/list/posting.html
>------------------------------------------------------------------------
> Julie Ann Connary
> | | Network Consulting Engineer
> ||| ||| Federal Support Program
> .|||||. .|||||. 13635 Dulles Technology Drive,
>Herndon VA 20171
> .:|||||||||:.:|||||||||:. Pager: 1-888-642-0551
> c i s c o S y s t e m s Email: jconnary@cisco.com
>
>------------------------------------------------------------------------
>**Please read:http://www.groupstudy.com/list/posting.html
------------------------------------------------------------------------
Julie Ann Connary
| | Network Consulting Engineer
||| ||| Federal Support Program
.|||||. .|||||. 13635 Dulles Technology Drive,
Herndon VA 20171
.:|||||||||:.:|||||||||:. Pager: 1-888-642-0551
c i s c o S y s t e m s Email: jconnary@cisco.com
------------------------------------------------------------------------
**Please read:http://www.groupstudy.com/list/posting.html
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