06-05-2006 01:55 AM - edited 03-03-2019 12:54 PM
HI ALL!
I've sumarized toward the core from each dist.i;m a little bit confused about the routing loop;the routing P is EIGRP.CAN U use static route to the null0.how is the procedure.PS Have a look to my config&the attachment:
core:
router eigrp 100
network 10.0.0.0
no auto-summary
DS1
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.3.0.0 255.255.0.0
DS2
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.2.0.0 255.255.0.0
DS3
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.4.0.0 255.255.0.0
DS4
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.5.0.0 255.255.0.0.
do i creat a null interface on each dist than advertised the route to null.how can i configure this depending on my diagram?
10xs
Ali
06-05-2006 02:37 AM
Hi Ali,
AFAIK if you just create a static route pointing to null0 interface on your Distribution Switch it should be ok.
eg
On your dist switch 1 you can configure something like this
ip route 10.3.0.0 255.255.0.0 null0
In same way you can have this static route on all your distribution switch where you have configured summarisation.
HTH, if yes please rate the post.
Ankur
06-05-2006 03:25 AM
hi 10xs for ur reply!
on the dist1 this config it will be like this:
DS1
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.3.0.0 255.255.0.0
int null0
!ip route 10.3.0.0 255.255.0.0 null0
on dist 2
DS2
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.2.0.0 255.255.0.0
!
int null0
!
ip route 10.2.0.0 255.255.0.0 null0
and so on;on all the remaining dist..ankur can u explain to me what happen without this command & with this command
10xs
ali
06-05-2006 03:40 AM
Hi Ali,
Lets me try to explain...
Lets take an example you have not configured static route pointing to null 0 interface so what could be the result. Your summarised route will be advertised to different routers and neighbors say the core router. Now if any node behind core router want to reach any of the specific routes from that summarised routes, the core router will fwd the request to your distribution router as it has learned the summarised route from distribution router.
Now lets say that particular route from summarised route is not available due to any reason or distrubution router is not aware of that specific route because that specific route is down what will happen in that case. The request may be sent to the default route if you have any on dstribution router and that default router may again send the request to distribution router and in this case ther may be a loop between a distribution router and default router.
If you have a static route pointing to null 0 interface on distribution router and even if any specific route is down from that summarised route then it will check the static route pointing to null 0 interface and will drop the packet and will prevent routing loop. Now this is one situation which can create rouitng loop and it all depends on your network and routing design not necessary that without static route pointing to null 0 interface you will get into routing loop but it is recommended that if you have summarised route better to have static route also pointing to null 0.
Check this link may be of help
http://www.cisco.com/en/US/tech/tk364/technologies_tech_note09186a00801c9a6e.shtml#topic1
Hope I am able to explain, if yes please rate the post.
Ankur
06-05-2006 03:58 AM
Hi ankur 10xs for ur reply!
have a look to this config;it is correct:
DS1
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.3.0.0 255.255.0.0
int null0
!ip route 10.3.0.0 255.255.0.0 null0
on dist 2
DS2
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.2.0.0 255.255.0.0
!
int null0
!
ip route 10.2.0.0 255.255.0.0 null0
10xs
06-05-2006 04:02 AM
Hi Ali,
That's perfect!!
Have a luck and nice stable network ;)
HTH, if yes please rate all post.
Ankur
06-05-2006 04:17 AM
HI ANKUR 10XS FOR UR HELP
DO I NEED TO CREAT 1ST A NULL INTERFACE IN EACH DIST IN THE NETWORK.THAN I CREAT A THE STATIC ROUTE TO NULL0.ANKUR B/W I DONT HAVE ROUTERS IN MY NETWORKS ALL IS L3 SWITCHS(6509-E)
10XS
ali
06-05-2006 04:26 AM
Hi Ali,
Yes you can very well create null0 interface on cat6k switch and then configure static route pointing to the null0 interface.
Have a look at this link
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/12_1e/comref/i1.htm#wp1265171
HTH, if yes please rate all post.
Ankur
06-05-2006 04:47 AM
HI 10XS FOR UR REPLY!
THE CONFIG ON ALL DIST LIKE THIS.COORECT ME IF I'M WRONG.
DS1
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.3.0.0 255.255.0.0
!
INT null0
!
ip route 10.3.0.0 255.255.0.0 null0
DS2
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.2.0.0 255.255.0.0
!
INT null0
!
ip route 10.2.0.0 255.255.0.0 null0
DS3
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
int gi0/1
ip address
ip summary-address eigrp 100 10.4.0.0 255.255.0.0
INT null0
!
ip route 10.4.0.0 255.255.0.0 null0
!
DS4
router eigrp 100
network 10.0.0.0
passive-interface default
no passive-interface gi0/1
no auto-summary
!
int gi0/1
ip address
ip summary-address eigrp 100 10.5.0.0 255.255.0.0
INT null0
!
ip route 10.5.0.0 255.255.0.0 null0
!
THIS CONFIG ITS CORRECT
10XS
ALI
06-05-2006 05:02 AM
hi Ankur,
first of all i like to wish you congratulation for your cisco job and can i have your new email ID
regards
Devang
06-05-2006 06:57 AM
Hi Ali,
Your config is perfect!!
Wish you a luck for your sweet and stable network.
HTH, if yes please rate the post.
Devang: Thanks for your wishes!! You can reach me on anky_is_yanky@yahoo.com
Regards,
Ankur
06-05-2006 08:46 PM
HI
Ankur i would also like to share u r e-mail ID hope u dnot mind.
Thanks
Mahmood
06-05-2006 10:25 PM
Hi Mahmood,
You are most welcome!!
Regards,
Ankur
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