From: Chris McGuire (cmcguire@firstdigital.com)
Date: Wed Apr 23 2008 - 17:49:44 ART
As far as I know, the 2 step process when redistributing from one protocol
to another is not documented. I learned in CCIE studies using IE products.
When redistributing from Protocol A to Protocol B:
1. Take "A" routes from route table. (show ip route "A")
2. Take all interfaces that are "connected" with this protocol.
For example with rule 2. If you have an interface:
Interface fastethernet 0/0
Ip add 1.1.1.1 255.255.255.0
Then you enable OSPF on that interface
Router ospf 1
Network 1.1.1.1 0.0.0.0 area 0
This route will not show up in this routers route table as ospf but will
still be a candidate when redistributing ospf into another protocol.
I am not fully sure how to determine what determines what is "connected"
with BGP. I would be interested in learning more about this.
Thanks
On 4/23/08 2:01 PM, "Noor.Yousuf@shell.com" <Noor.Yousuf@shell.com> wrote:
> Chris,
>
> Thanks for looking into the issue, I did the same setup and my assumption is
> same. Yes, I know I can use redistribute static to make it work but I really
> need to understand why BGP has this behavior
> Any cisco reference or document would be greatly appreciated.
>
> Thanks,
> Noor
>
> -----Original Message-----
> From: Chris McGuire [mailto:cmcguire@firstdigital.com]
> Sent: woensdag 23 april 2008 18:03
> To: Huan Pham; 'Andy Cole'; Yousuf, Noor S SITI-ITIBTAE;
> ccielab@groupstudy.com
> Subject: Re: bgp to ospf redistribution question
>
>
> After labbing it up, I have come up with this:
>
> ip route 100.100.100.0 255.255.255.0 null 0
> ip route 101.101.101.0 255.255.255.0 10.10.10.1
>
> Both are static routes.
>
> They are both added to the bgp table with the network statement.
>
> However, the first route is a "connected static" route and can be considered
> connected.
>
> The 2nd route is not connected so it is just static.
>
> When redistributing BGP into OSPF it will grab all BGP routes (show ip orute
> bgp) and all "Connected BGP" routes.
>
> I am assuming that the first route is considered a "connected bgp" route and
> the 2nd is not. Therefore only the 1st route is eligible to be redistributed
> from BGP to OSPF. The only way to get the other route in ospf is by
> redsistributing it from static to ospf.
>
> Any input greatly appreciated..
>
> Chris
>
> On 4/23/08 9:09 AM, "Huan Pham" <huan.pham@valuenet.com.au> wrote:
>
>> Hi Chris,
>>
>> BTW, I do not think that router checks if the next hop (for static route)
>> reachable or not before the static route is installed in the routing table,
>> unless you configure object tracking! I believe you meant the next hop is
>> not on directly connected subnet.
>>
>> Cheers,
>>
>> Huan
>>
>> -----Original Message-----
>> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>> Chris McGuire
>> Sent: Thursday, 24 April 2008 12:22 AM
>> To: Andy Cole; Noor.Yousuf@shell.com; ccielab@groupstudy.com
>> Subject: Re: bgp to ospf redistribution question
>>
>> Also, does the other route show up in the route table doing the
>> redistribution?
>>
>> Show ip route static?
>>
>> If the next hop address is not reachable, it will not show up in the route
>> table as a static and will therefore not be a candidate for the network
>> statement under BGP.
>>
>> Thanks
>> Chris
>>
>>
>> On 4/23/08 8:11 AM, "Andy Cole" <Andy.Cole@foremostfarms.com> wrote:
>>
>>> gp redistribute-
>>
>> Chris S. McGuire
>> Network Engineer
>> Phone: 801-456-1028
>> Fax: 801-456-1010
>> Email: cmcguire@firstdigital.com
>>
>>
>> Pass the CCIE in six weeks, Guaranteed!
>> http://www.certscience.com/CCIE
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>> Pass the CCIE in six weeks, Guaranteed!
>> http://www.certscience.com/CCIE
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>>
>>
>
> Chris S. McGuire
> Network Engineer
> Phone: 801-456-1028
> Fax: 801-456-1010
> Email: cmcguire@firstdigital.com
>
>
> Pass the CCIE in six weeks, Guaranteed!
> http://www.certscience.com/CCIE
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
>
>
Chris S. McGuire
Network Engineer
Phone: 801-456-1028
Fax: 801-456-1010
Email: cmcguire@firstdigital.com
Pass the CCIE in six weeks, Guaranteed!
http://www.certscience.com/CCIE
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