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BGP/EIGRP routing

 
 
MC
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      04-17-2007
OK, I thought I had this working, but I have a local EIGRP LAN learned
route and a BGP WAN learned route, I want the BGP learned route to be
prefered unless goes away then will use the EIGRP learned route.


However, when route are learned by one, the other never supercedes the
other.

If BGP is the route learned at the time, EIRGP can come and go and never
overrides the BGP route, If EIGRP route is the one learned at the time
(clearing BGP routes) BGP learned routes can come and go but the EIGRP
learned route will be the one always in the routing table until clearing
the EIGRP routes.

What am I missing, not had much sleep so not thinking well but need to
figure this out.

Thanks much for the help.
 
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Thrill5
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      04-18-2007
The EIGRP learned route will be preferred over the BGP route because the
EIGRP route is an "internal" route and the BGP is "external". You can try
to fix this by adjusting the metrics of the BGP routes when redistributing
them into EIGRP. But I don't think this will fix your problem because by
default EIGRP has an admin distance of 90, and I believe BGP is 110 and the
routes are being learned on the router running both EIGRP and BGP. To see
this, do a "show ip route" and you will see that the EIGRP routes have a
lower "Admin" distance than the BGP routes. Each route will show the metric
like [90/92922], where the number before the "/" is the admin distance, and
the number afterward is the routing metric. The routing metric is only used
if the admin distance is the same.

Scott


"MC" <(E-Mail Removed)> wrote in message
news:nrbVh.24523$(E-Mail Removed).. .
> OK, I thought I had this working, but I have a local EIGRP LAN learned
> route and a BGP WAN learned route, I want the BGP learned route to be
> prefered unless goes away then will use the EIGRP learned route.
>
>
> However, when route are learned by one, the other never supercedes the
> other.
>
> If BGP is the route learned at the time, EIRGP can come and go and never
> overrides the BGP route, If EIGRP route is the one learned at the time
> (clearing BGP routes) BGP learned routes can come and go but the EIGRP
> learned route will be the one always in the routing table until clearing
> the EIGRP routes.
>
> What am I missing, not had much sleep so not thinking well but need to
> figure this out.
>
> Thanks much for the help.



 
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MC
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      04-18-2007
Thrill5 wrote:
> The EIGRP learned route will be preferred over the BGP route because the
> EIGRP route is an "internal" route and the BGP is "external". You can try
> to fix this by adjusting the metrics of the BGP routes when redistributing
> them into EIGRP. But I don't think this will fix your problem because by
> default EIGRP has an admin distance of 90, and I believe BGP is 110 and the
> routes are being learned on the router running both EIGRP and BGP. To see
> this, do a "show ip route" and you will see that the EIGRP routes have a
> lower "Admin" distance than the BGP routes. Each route will show the metric
> like [90/92922], where the number before the "/" is the admin distance, and
> the number afterward is the routing metric. The routing metric is only used
> if the admin distance is the same.
>
> Scott
>
>
> "MC" <(E-Mail Removed)> wrote in message
> news:nrbVh.24523$(E-Mail Removed).. .
>> OK, I thought I had this working, but I have a local EIGRP LAN learned
>> route and a BGP WAN learned route, I want the BGP learned route to be
>> prefered unless goes away then will use the EIGRP learned route.
>>
>>
>> However, when route are learned by one, the other never supercedes the
>> other.
>>
>> If BGP is the route learned at the time, EIRGP can come and go and never
>> overrides the BGP route, If EIGRP route is the one learned at the time
>> (clearing BGP routes) BGP learned routes can come and go but the EIGRP
>> learned route will be the one always in the routing table until clearing
>> the EIGRP routes.
>>
>> What am I missing, not had much sleep so not thinking well but need to
>> figure this out.
>>
>> Thanks much for the help.

>
>

That is what I thought.

However, the behavior on my router is that if the BGP route is learned
first, EIGRP learned route never overrides until I clear the BGP route ?

That is what is confusing ?

Thanks much for the help.
 
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Merv
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Posts: n/a
 
      04-18-2007
On Apr 18, 6:40 am, MC <(E-Mail Removed)> wrote:
> Thrill5 wrote:
> > The EIGRP learned route will be preferred over the BGP route because the
> > EIGRP route is an "internal" route and the BGP is "external". You can try
> > to fix this by adjusting the metrics of the BGP routes when redistributing
> > them into EIGRP. But I don't think this will fix your problem because by
> > default EIGRP has an admin distance of 90, and I believe BGP is 110 and the
> > routes are being learned on the router running both EIGRP and BGP. To see
> > this, do a "show ip route" and you will see that the EIGRP routes have a
> > lower "Admin" distance than the BGP routes. Each route will show the metric
> > like [90/92922], where the number before the "/" is the admin distance, and
> > the number afterward is the routing metric. The routing metric is only used
> > if the admin distance is the same.

>
> > Scott

>
> > "MC" <(E-Mail Removed)> wrote in message
> >news:nrbVh.24523$(E-Mail Removed). ..
> >> OK, I thought I had this working, but I have a local EIGRP LAN learned
> >> route and a BGP WAN learned route, I want the BGP learned route to be
> >> prefered unless goes away then will use the EIGRP learned route.

>
> >> However, when route are learned by one, the other never supercedes the
> >> other.

>
> >> If BGP is the route learned at the time, EIRGP can come and go and never
> >> overrides the BGP route, If EIGRP route is the one learned at the time
> >> (clearing BGP routes) BGP learned routes can come and go but the EIGRP
> >> learned route will be the one always in the routing table until clearing
> >> the EIGRP routes.

>
> >> What am I missing, not had much sleep so not thinking well but need to
> >> figure this out.

>
> >> Thanks much for the help.

>
> That is what I thought.
>
> However, the behavior on my router is that if the BGP route is learned
> first, EIGRP learned route never overrides until I clear the BGP route ?
>
> That is what is confusing ?
>
> Thanks much for the help.



That would be a bug

 
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Darren Green
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      04-18-2007

"Thrill5" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed). ..
> The EIGRP learned route will be preferred over the BGP route because the
> EIGRP route is an "internal" route and the BGP is "external". You can try
> to fix this by adjusting the metrics of the BGP routes when redistributing
> them into EIGRP. But I don't think this will fix your problem because by
> default EIGRP has an admin distance of 90, and I believe BGP is 110 and
> the routes are being learned on the router running both EIGRP and BGP. To
> see this, do a "show ip route" and you will see that the EIGRP routes have
> a lower "Admin" distance than the BGP routes. Each route will show the
> metric like [90/92922], where the number before the "/" is the admin
> distance, and the number afterward is the routing metric. The routing
> metric is only used if the admin distance is the same.
>
> Scott
>

eBGP has an AD of 20 and iBGP a default AD of 200. As EIGRP is 90 this would
ordanarily be preferred over iBGP but not eBGP.

There is no config to go off so it would be difficult to say whether other
influencing factors relating to EIGRP or BGP were causing the issue.

Regards

Darren


 
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John Agosta
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      04-18-2007

"MC" <(E-Mail Removed)> wrote in message
news:nrbVh.24523$(E-Mail Removed).. .
> OK, I thought I had this working, but I have a local EIGRP LAN learned
> route and a BGP WAN learned route, I want the BGP learned route to be
> prefered unless goes away then will use the EIGRP learned route.
>
>


You do not state how BGP learns the route in question - Is it an iBGP path
or an eBGP path ?

Why don't you show us the following two outputs:

show ip route

and

show ip bgp



 
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