Description

All PPPoE subscribers unable to login after upgrading software to 15.1R4 (Tomcat). The 'subscriber-management' was enabled on this version.

Symptoms

A capture on the specified vLAN interface, shows that PPP IPCP negotiation failed:

labroot@jtac-MX480-r008-re0# run show subscribers stacked-vlan-id 101 vlan-id 100
Interface IP Address/VLAN ID User Name LS:RI
xe-2/0/0.3221225472 0x8100.101 0x8100.100 default:default

labroot@jtac-MX480-r008-re0# run monitor traffic interface xe-2/0/0.3221225472 no-resolve size 1500
verbose output suppressed, use <detail> or <extensive> for full protocol decode
Address resolution is OFF.
Listening on xe-2/0/0.3221225472, capture size 1500 bytes

03:53:44.672898 In PPPoE PADI
03:53:44.672970 Out PPPoE PADO [AC-Name "jtac-MX480-r008-re0"] [Service-Name] [AC-Cookie UTF8]
03:53:44.673684 In PPPoE PADR [Service-Name] [AC-Cookie UTF8]
03:53:44.684338 Out PPPoE PADS [ses 1] [Service-Name] [AC-Name "jtac-MX480-r008-re0"] [AC-Cookie UTF8]
03:53:44.685404 In PPPoE [ses 1]LCP, Conf-Request (0x01), id 1, length 16
03:53:44.688452 In PPPoE [ses 1]LCP, Conf-Ack (0x02), id 14, length 21
03:53:44.690573 In PPPoE [ses 1]CHAP, Response (0x02), id 161, Value 7d4ed7716f26d381a9579b67e6bf1b7b, Name spirent
03:53:44.795352 In PPPoE [ses 1]IPCP, Conf-Request (0x01), id 1, length 12
03:53:44.797391 In PPPoE [ses 1]IPCP, Conf-Ack (0x02), id 77, length 12
03:53:44.797548 In PPPoE [ses 1]IPCP, Conf-Request (0x01), id 2, length 12
03:53:44.944642 Out PPPoE PADT [ses 1]  <--- no out ipcp conf-req
03:53:44.945070 In PPPoE PADT [ses 1]
03:53:44.945100 In PPPoE [ses 1]LCP, Term-Ack (0x06), id 15, length 6

Solution

Enabled PPP traceoption found bbe-smgd daemon cannot get un-numbered IFL. 

Aug 16 03:28:49.344046 NACK received for profile request with id=0xa608040 from bbe-smgd daemon: Failed to get unnumbered ifl retry FALSE
Check configuration: 
jw-pppoe {
    interfaces {
        pp0 {
            unit "$junos-interface-unit" {
            ...
                family inet {
                    unnumbered-address lo0;   <--- the unnumbered ifl is lo0 without unit
                }
            }
        }
    }
}
After upgrading to 15.1R4 (tomcat), the subscriber-management software structure changed. The 'bbe-smgd' is a new daemon and cannot identify 'unnumbered ifl without unit' . This configuration worked fine in version 13.3R9.

Set 'unnumbered ifl with unit' to resolve this issue. 

jw-pppoe {
    interfaces {
        pp0 {
            unit "$junos-interface-unit" {
            ...
                family inet {
                    unnumbered-address lo0.0;   <---- set the unnumbered ifl to lo0.0
                }
            }
        }
    }
}