iosxr

[Ratheesh mv]

Hi all ,

First time we are going to put ASR 9k (IOSXR) dual RP router in the production. I don't have previous experience with dual RP ASR9K routers .I would like to clear my below doubts with ASR9K experts.

1)Do we have to separately install IOSXR image in active and standby RP and how to check that current IOSXR image of active and standby RP(command)

2)Do we have to manually enable NSR/NSF for redundancy also is there any CPU impact if enable NSR/NSF?

3)Is NSR/NSF mandatory configuration on dual RP router ?

4)If there is no NSR/NSF what is going to happen when active RP goes down ?

can anyone share good study material to understand about dual RP configuration ?

Thanks in advance  

[tkarnani]

Hi Ratheesh,

you can review the high availability guide

https://www.cisco.com/c/en/us/td/docs/iosxr/asr9000/hardware-install/overview-reference/b-asr9k-overview-reference-guide/b-asr9k-overview-reference-guide_chapter_011.pdf

1. you will install the packages once, it will automatically sync with the standby RSP

NSR is a recommended configuration, you can turn it off if you wish. it keeps the protocol from flapping causing a network churn in case an RSP fails.

the goal is to have an RSP fail without having to purge and re-learn prefixes/adjacency etc

[smilstea]

1)Do we have to separately install IOSXR image in active and standby RP and how to check that current IOSXR image of active and standby RP(command) [SM] - No, if the standby tries to boot with no image or a different image it will sync to the active RSP for the correct image and configuration

2)Do we have to manually enable NSR/NSF for redundancy also is there any CPU impact if enable NSR/NSF? [SM] - yes you need to enable per protocol, NSR and NSF do have CPU and memory impact.

3)Is NSR/NSF mandatory configuration on dual RP router ? [SM] - Not mandatory but virtually nobody runs without them. If the active RSP goes down you dont want to waste 5+ minutes relearning the entire BGP table or blackholing traffic

4)If there is no NSR/NSF what is going to happen when active RP goes down ? [SM] - you lose all routes for that protocol as the neighborships will bounce.

[SM] - So dual RP will sync the two RPs (RSPs) to a point, the OS and configuration are synced. Other files are not synced. With NSR and NSF session state for your protocol is synced between the two RSPs so both RSPs have communication to the peer and the same routes etc. Any action you take on the active will get synced to the standby, such as software change, and config change.

Sam