In case of a fibre cut, dyn-ip clients will not get logged out as the client couldn’t send the disconnect message to the BNG.
In this case BNG should monitor the subscriber and delete the session when there is now incoming packets from the client.
Sometime you will notice that the session will not get deleted in BNG and when the fibre cut restores, same client wouldn’t be able to login to the BNG until we clear the old session.
You will notice the subscriber online even when there is a fibre cut and subscriber will not get logged out after idle time.
root@BNG> show subscribers user-name x.x.x.x extensive
Interface IP Address/VLAN ID User Name LS:RI
demux0.3221512664 x.x.x.x x.x.x.x default:default
Customer has configured to monitor the session idle timeout by monitoring ingress traffic.
root@BNG> show configuration access profile <profile-name>
accounting-order radius;
authentication-order radius;
radius {
authentication-server [ x.x.x.x];
accounting-server [ x.x.x.x];
options {
client-authentication-algorithm direct;
client-accounting-algorithm direct;
service-activation {
dynamic-profile optional-at-login;
}
session-options {
client-idle-timeout-ingress-only;
Also we can see that customer has the actual-transit-statistics knob as well.
root@BNG> show configuration dynamic-profiles ip-demux-profile
routing-instances {
"$junos-routing-instance" {
interface "$junos-interface-name";
routing-options {
access {
route $junos-framed-route-ip-address-prefix {
qualified-next-hop "$junos-interface-name";
metric "$junos-framed-route-cost";
preference "$junos-framed-route-distance";
interfaces {
demux0 {
unit "$junos-interface-unit" {
actual-transit-statistics;
proxy-arp;
demux-options {
underlying-interface "$junos-underlying-interface";
family inet {
demux-source {
$junos-subscriber-demux-ip-address;
filter {
input "$junos-input-filter" precedence 50;
output "$junos-output-filter" precedence 50;
unnumbered-address "$junos-loopback-interface";
If you see the extensive output of the subscriber, you could see a large value as idle timeout.
root@BNG> show subscribers interface demux0.3221512664 extensive
Type: DYN-IP
User Name: x.x.x.x
IP Address: x.x.x.x
Domain name server inet: x.x.x.x
Logical System: default
Routing Instance: default
Interface: demux0.3221512664
Interface type: Dynamic
Underlying Interface: demux0.915
Dynamic Profile Name: ip-demux-profile
Dynamic Profile Version: 1
MAC Address:xx:xx:xx:xx
Session Timeout (seconds): 605441
State: Active
Radius Accounting ID: 876809954
Session ID: 876809954
PFE Flow ID: 618754
VLAN Id: 915
Login Time: 2025-02-18 10:16:02 UTC
Service Sessions: 1
IPv4 Input Filter Name: 1000M-demux0.3221512664-in
IPv4 Output Filter Name: 1000M-demux0.3221512664-out
Accounting interval: 600
Dynamic configuration:
junos-input-filter: 1000M
junos-input-ipv6-filter: 1000Mv6
junos-output-filter: 1000M
junos-output-ipv6-filter: 1000Mv6
When we check the configuration we could see that there is no idle timeout configured, and which will tent to take the default idle timeout which is too high.
Need to configure client-idle-timeout knob under under access profiles to adjust the idle timeout.
Example :
profile radius-profile {
client-idle-timeout 10;
Please refer KB37479 [juniper.net] & Session Options for Subscriber Access for more details.