I would recommend to check out the system management config guide here: https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r7-1/system-management/configuration/guide/b-system-management-cg-asr9000-71x/b-system-management-cg-asr9000-71x_chapter_010.html?bookSearch=true
There are three scale profiles available on your router:
The default scale profile that supports deployments that require large Layer 2 MAC tables (up to 512,000 entries) and a relatively small number of Layer 3 routes (less than 512,000).
The Layer 3 scale profile that supports deployments that require more Layer 3 routes (up to 1 million) and smaller Layer 2 MAC tables (less than 128,000 entries).
The Layer 3 XL scale profile that supports deployments that require a very large number of Layer 3 routes (up to 1.3 million) and minimal Layer 2 functionality. Note that the support for up to 1.3 million routes is split into IPv4 scaled support and IPv4/IPv6 scaled support. You can configure up to 1.3 million IPv4 routes, or up to 1 million IPv4 routes with 128,000 IPv6 routes. The layer 3 XL scale profile does not support video monitoring.
You can increase the memory available for BGP by configuring the Layer 3 XL profile on the Cisco ASR9000 Series Router using the hw-module profile scale l3xl command. However, this reduces the memory available for some other processes. To activate the new profile, you need to manually reboot the system.
The memory for BGP and the other processes can be verified by using the following commands before and after the configuration:
show processes memory detail
show bgp process performance-statistics | include RLIMIT : This command is available only from Cisco IOS-XR release 6.1.x onwards.
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Anthony Sylvester