Supported Platforms
Related Documentation
- EX, J, M, MX, PTX, QFX, T Series
- krt-nexthop-ack-timeout
- J, M, PTX, SRX, T Series
- Example: Optimizing Route Reconvergence by Enabling Indirect Next Hops on the Packet Forwarding Engine
indirect-next-hop-change-acknowledgements
Syntax
Hierarchy Level
Release Information
Statement introduced in Junos OS Release 12.2.
Description
Configure the routing protocol process (rpd) to request an acknowledgement when creating a new forwarding next hop.
During an indirect next-hop change sequence, the routing device might create a new forwarding next hop that is referenced by the indirect next hop. If the indirect-next-hop-change-acknowledgements statement is configured, the routing protocol process requests an acknowledgement when creating the new forwarding next hop. When the routing protocol process receives the acknowledgement, this indicates that all PICs have received the new forwarding next hop and it is then safe to change the indirect next hop to reference the new forwarding next hop. This prevents packet loss when changing the indirect next hop by ensuring that all PICs have consistent state information for the new forwarding next hop.
The routing protocol process is not requesting an acknowledgement for the indirect next hop itself. Rather, the routing protocol process is requesting an acknowledgement for the new forwarding next hop that the indirect next hop is going to reference. In the case when the forwarding next hop is an existing one (meaning that it is already installed in the forwarding table), the routing protocol process does not request an acknowledgement, even if the indirect-next-hop-change-acknowledgements statement is configured.
We recommend that the indirect-next-hop-change-acknowledgements statement be configured when protection mechanisms are being used. This includes MPLS RSVP protection such as fast reroute (FRR) as well as interior gateway protocol (IGP) loop-free alternate (LFA) link or node protection. If there is no protection mechanism being used in the network, the indirect-next-hop-change-acknowledgements statement does not provide any benefit and might increase packet loss.
Default
Disabled by default in all platforms except PTX Series, where it is enabled by default.
Options
indirect-next-hop-change-acknowledgements—Enable acknowledgements.
no-indirect-next-hop-change-acknowledgements—Explicitly disable acknowledgements.
Required Privilege Level
routing—To view this statement in the configuration.
routing-control—To add this statement to the configuration.
Related Documentation
- EX, J, M, MX, PTX, QFX, T Series
- krt-nexthop-ack-timeout
- J, M, PTX, SRX, T Series
- Example: Optimizing Route Reconvergence by Enabling Indirect Next Hops on the Packet Forwarding Engine
Published: 2013-10-10
Supported Platforms
Related Documentation
- EX, J, M, MX, PTX, QFX, T Series
- krt-nexthop-ack-timeout
- J, M, PTX, SRX, T Series
- Example: Optimizing Route Reconvergence by Enabling Indirect Next Hops on the Packet Forwarding Engine