Routing
Routing

ISIS Overload

02.06.12   |  
‎02-06-2012 05:18 PM

Hi Experts

 

1- what is the timeout means when you configure overload and how if there is timeout configure the overload it's not active

 

2- I configure "advertise-high-metrics" the overload disappear but still I am seeing the routes with metric of 10  is that normal not a maximum one

 

Thanks a lot

BR ,,,
4 REPLIES
Routing

Re: ISIS Overload

02.09.12   |  
‎02-09-2012 09:41 AM
http://www.juniper.net/techpubs/en_US/junos11.4/topics/usage-guidelines/routing-configuring-is-is-to...
Answer 1.
"If the time elapsed after the IS-IS instance is enabled is less than the specified timeout, overload mode is set."
The "timeout" knob would typically be used to keep the router in "overload" for some period of time after the router (or routing process) restarts.  For example, during a maintenance event.
Answer 2.
The "advertise-high-metric" is only valid, while the router is in overload mode.  Maybe your timeout value was reached?
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Routing

Re: ISIS Overload

02.10.12   |  
‎02-10-2012 06:28 AM

Hi benb

 

1- so if the timer is set the ISIS will not be activated unless RDP / ISIS process  crashed and it will be enabled for the period of time that  you specified

 

2-  I mean after I enable the "advertise-high-metric" I am not able to see the router mark as overload in show Isis database but the problem I was not able to see the route masked with high metric , is that normal

 

BR ,,,
Routing

Re: ISIS Overload

02.10.12   |  
‎02-10-2012 07:28 AM

ralwarrag wrote:

Hi benb

 

1- so if the timer is set the ISIS will not be activated unless RDP / ISIS process  crashed and it will be enabled for the period of time that  you specified

 

2-  I mean after I enable the "advertise-high-metric" I am not able to see the router mark as overload in show Isis database but the problem I was not able to see the route masked with high metric , is that normal

 


1. If the timer is set, it means the router will be "overloaded" until the timer expires.  The timer starts whenever the routing process starts (e.g. router startup, rpd restart).  For example. Overload timeout is set to 300.  The routing process is restarted.  This means the advertisements would have the overload bit set for 5 minutes.  After the 5 minutes expired the overload would be removed.

 

2. Yes, that is normal.  When "advertise-high-metric" is configured, isis does *not* set the overload bit.  Rather, it only sets the metric to 63 or 16777214. Depending on whether or not wide-metrics are enabled.  This allows the "overloaded" router to be used for transit, as a last resort.

Routing

Re: ISIS Overload

02.10.12   |  
‎02-10-2012 07:34 AM

Thank you

BR ,,,