The configuration shown in the exhibit is both syntactically correct and complete for its intended purpose. In Nokia's SR OS, the as-override command can be configured at either the BGP group level or, for more granular control, at the BGP neighbor level. The exhibit correctly places the as-override command within the neighbor 10.1.1.1 context, which is a valid configuration hierarchy. This command instructs the PE router to replace the customer's AS number (65501) with its own AS number in BGP updates sent to that specific CE neighbor, effectively preventing the BGP loop-prevention mechanism from incorrectly dropping the routes.

B. 'as-override' should be configured under the BGP context.

This is incorrect. The as-override command is not a global BGP parameter; it is applied on a per-group or per-neighbor basis to control ASPATH modification for specific peers.

C. 'as-override' should be configured under the group context.

This is not mandatory. While as-override can be configured at the group level to apply to all neighbors within that group, configuring it at the neighbor level (as shown) is also valid and often preferred.

D. 'as-override' should not be part of this configuration.

This is incorrect. The question explicitly states the goal is to use the AS-override method to prevent BGP loops in a VPRN, which is the exact scenario this feature is designed for.

1. Nokia 7750 SR OS R20.10.R1 MPLS Guide, Section: VPRN BGP PE-CE Routing Protocol Support

Page 398, "AS Override": "To avoid this problem, the PE router can be configured to change the AS number of the customer site to its own AS number in the AS path of the BGP update. This is accomplished by configuring the as-override option on the PE router that is a neighbor of the CE router." This confirms the feature's purpose.

2. Nokia 7750 SR OS R20.10.R1 BGP Command Reference, Section: BGP Command Reference

Page 119, as-override: This section details the command syntax and context. It shows the command is available under config>router>bgp>group and config>router>bgp>group>neighbor. This confirms the configuration in the exhibit (neighbor level) is a valid context. The document states, "This command enables AS override on a per-group or per-neighbor basis."