In subscriber management environment during subscriber authentication, RADIUS may add Frame-Route attribute to describe routes reachable via subscriber's CPE. These routes are programmed on BNG device as access routes. In some cases it's needed to change subscriber's routing information. In JunOS it's possible to re-program subscriber's routing information without terminating subscriber's session by sending RADIUS change of authorization (CoA) message. Assume that originally programmed subscriber prefix was x.x.x.x/a and it's needed to change prefix length for the same prefix via CoA. I.e., CoA message will instruct BNG to program route x.x.x.x/b. When prefix remains the same and prefix length is changing via CoA such change doesn't happen, which is JunOS bug described in this KB

The problem happens when operator needs to change subscriber's prefix length for the same access prefix via CoA. Bbe-smgd traceoptions will print error message similar to:

bbe_route_dprof_create_framed_full_config:Framed route IPV4 dprof_af IPV4 prefixLen = 25, value = 10.0.0.0
bbe_route_dprof_create_framed_full_config: nh-ifl pp0.3221225472 being used for prefix 10.0.0.0 profile DYN-PROF$$01
bbe_route_dprof_create_framed_full_config: route metric 1 being used for prefix 10.0.0.0 profile DYN-PROF$$01
ERR: bbe_route_dprof_create_framed_full_config: dprof_get_string FAILED for IPV4 route prefix DYN-PROF$$01 error 17

As a workaround, this change of access route's prefix length can be split in two steps:

1. In one CoA message instructs BNG to remove access route that needs to be changed.
2. In second CoA message instructs BNG to add the same prefix with the new prefix length.

This problem is fixed in PR1781938. For the list of releases having fix of this problem and further information please refer to https://prsearch.juniper.net/problemreport/PR1781938