06-06-2008 06:14 AM - edited 03-03-2019 10:16 PM
Between two routers I have 2 E1 links.I am running eigrp want to make 1st link primary and 2nd link secondary, what i want to achieve my all traffic should move over 1st link a) wherever this link is fully utalized traffic should move on 2nd link also .b) whenever 1st link performance is degraded or relibility goes down then traffic should always move over secondary link.
Please let me know if its possible.
06-06-2008 07:37 AM
ajay
While EIGRP certainly allows you to configure so that there is a primary link and a backup link, EIGRP does not provide the ability to shift traffic between links based on the load of the primary or based on degraded performance of the primary.
While I have not used it and can not speak from experience, I understand that using OER may allow you to do something like this.
HTH
Rick
06-06-2008 07:45 AM
Hi Rick,
Can u please explain me how to configure OER in this scenario pls .
06-10-2008 10:34 PM
AFAIK, You either need BGP peering or static route between your routers to use OER.
As you have only one router, you can make it as both MC/BR and configure a static route pointing to the other router.
Below is the config guide for OER,
http://www.cisco.com/en/US/docs/ios/oer/configuration/guide/12_4t/oer_12_4t_book.html
HTH,
Nagendra
06-09-2008 09:11 AM
Hello Rick,
by changing the k-values inside the eigrp process you could take in account the load in the EIGRP metrics calculation.
However, I'm afraid it could lead to some instabilities if it is too fast in reacting to changing load values.
I agree OER could be a better safer solution but I haven't direct experience too.
Best regards
Giuseppe
06-10-2008 03:40 AM
EIGRP doesn't read the metrics off the interface dynamically, so this won't work for the moment. The metrics are only read at the time the interface is brought up.
Dynamically reading metrics are planned, but not available/documented right now.
:-)
Russ
06-10-2008 06:02 AM
Hello Russ,
this is something I didn't know I thought EIGRP was able to read the interface load parameters from time to time.
If this is not true the load part of the EIGRP metrics is useless at the moment.
I understand that reading the interface parameters will lead to an increase in cpu usage and can lead to an increased frequency in eigrp topology changes and recalculations
Best Regards
Giuseppe
06-10-2008 06:21 AM
this is also something which i am also not aware about I have always seen in eigrp running enviroment if we change the bw,delay if recalculates the metric automatically we don't need to reset the eigrp to recalculate the changes .
06-10-2008 08:56 AM
ajay
You are not talking about the same things that Russ is, so what he says (about the load parameter) does not apply to your comment about bw and delay.
You are right that if you change bw or delay then EIGRP should pick up that change and recalculate its metric. But Russ is right that EIGRP looks at the load when it initially calculates the metric and does not look back to see if load has changed.
HTH
Rick
07-01-2008 05:15 AM
"You are right that if you change bw or delay then EIGRP should pick up that change and recalculate its metric"
This is because these are manual configurations on the interface.... When you change the bandwidth or delay on the interface, EIGRP resets the neighbor adjacencies on that interface so it can pick up the changes. If you do a log-neighbor-changes, you should see the reset.
In more recent code, we will do a soft reset, or rather a graceful restart, rather than a hard reset. When the neighbor's reset, we will also pick up the load, utilization, and other parameters.
:-)
Russ
06-06-2008 08:48 AM
hi,
you may also use HSRP TRACKING FEATURE if you topology suits with it.
rgds/shiva
06-06-2008 08:50 AM
Shiva,
I have only single route each end .
06-06-2008 09:10 AM
yes,
i read your question wrongly.
rgds/shiva
06-09-2008 09:53 AM
use Ip sla command for both latency and packet loss and based on track you can shift the traffic.
http://www.cisco.com/en/US/docs/ios/12_4/ip_sla/configuration/guide/hsthresh.html
regards
Ashish GUpta
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