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Stuck-inactive EIGRP

grapevine
Level 1
Level 1

How long does a router running EIGRP stay in the stuck-inactive state?

Is there a recovery mechanism?

1 Accepted Solution

Accepted Solutions

Hello Traian,

You are very correct that the default active time is 3 minutes. However, all recent IOSes support a feature called SIA-Query that allows a router to ask its neighbor whether it is still processing its Query, and extend the active time if a corresponding SIA-Reply has been received.

A router supporting the SIA-Query mechanism would wait one half of the active timer, that is, 90 seconds, and send a SIA-Query to the unresponsive neighbor after that. If a SIA-Reply is received, the router will wait another 90 seconds, then send another SIA-Query. At most three SIA-Queries can be sent during the Active state, which amounts in total to 6 minutes (initial 90 seconds plus each responded SIA-Query providing next extra 90 seconds, in total 4x90 = 360 seconds). So a router can wait in the Active state for up to 6 minutes in default setting.

Ranji, you are asking about how long a router can stay in "stuck-inactive". This is in fact not a correct question - the name of the event is Stuck-In-Active, and it is not a state but rather a name of a particular action taken to resolve a situation when a Reply cannot be obtained in a reasonable time (6 minutes as explained before). If no Reply has been received after this time, the unresponsive neighbor is considered Stuck-In-Active and the adjacency toward that neighbor is torn down. This is all there is to Stuck-In-Active. The Stuck-In-Active does not have any duration - it is only an action taken to recover from an unresponsive neighbor.

Best regards,
Peter

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2 Replies 2

Traian Bratescu
Level 1
Level 1

The default for receiving a reply to the query is 3 minutes - it can be changed with

timers active-time [time-limit | disabled], where time-limit is in minutes

 

As for the recovery, the neighbourship with the router that did not reply to the query will be dropped which will trigger the redraw of those particular routes.

 

Traian 

Hello Traian,

You are very correct that the default active time is 3 minutes. However, all recent IOSes support a feature called SIA-Query that allows a router to ask its neighbor whether it is still processing its Query, and extend the active time if a corresponding SIA-Reply has been received.

A router supporting the SIA-Query mechanism would wait one half of the active timer, that is, 90 seconds, and send a SIA-Query to the unresponsive neighbor after that. If a SIA-Reply is received, the router will wait another 90 seconds, then send another SIA-Query. At most three SIA-Queries can be sent during the Active state, which amounts in total to 6 minutes (initial 90 seconds plus each responded SIA-Query providing next extra 90 seconds, in total 4x90 = 360 seconds). So a router can wait in the Active state for up to 6 minutes in default setting.

Ranji, you are asking about how long a router can stay in "stuck-inactive". This is in fact not a correct question - the name of the event is Stuck-In-Active, and it is not a state but rather a name of a particular action taken to resolve a situation when a Reply cannot be obtained in a reasonable time (6 minutes as explained before). If no Reply has been received after this time, the unresponsive neighbor is considered Stuck-In-Active and the adjacency toward that neighbor is torn down. This is all there is to Stuck-In-Active. The Stuck-In-Active does not have any duration - it is only an action taken to recover from an unresponsive neighbor.

Best regards,
Peter