The customer noticed in Junos 22.4R3-S5 that some subscribers cannot establish a DS-Lite tunnel.
For example, You can build the first softwire to fe80:1000:0:1::4214 without an issue,
But later, if you try to build another softwire to fe80:1000:0:1::4215, it will fail.
user@mx480> show services sessions
mams-3/3/0 (ams0)
Service Set: SSET-LODZ01F, Session: 100663298, ALG: icmp, Flags: 0x100180000, IP Action: no, Offload: no, Asymmetric: no
Softwire fe80:1000::10 -> fe80:1000:0:1::4214
ICMP 192.168.11.2 -> 10.8.8.8 Forward I 1
ICMP 10.8.8.8 -> 172.18.253.130 Forward O 1
Service Set: SSET-LODZ01F, Session: 134217729, ALG: none, Flags: 0x80080000, IP Action: no, Offload: no, Asymmetric: no
DS-LITE fe80:1000::10 -> fe80:1000:0:1::4214 Forward I 1
DS-LITE fe80:1000:0:1::4214 -> fe80:1000::10 Forward O 1
user@mx480>
In the MS-MPC pic console(in this sample we are using mams-3/3/0), you can see the softwire Plugin ID 8 stuck there forever.
Because this stuck plugin ID 8, it prevents further softwire from being built.
user@mx480> start shell user root
Password:
root@mx480 # telnet -Ji fpc3.pic3
Trying 128.0.4.19...
Connected to fpc3.pic3.
Escape character is '^]'.
login: root
root@ms33%
root@ms33% mspdbg-cli -ps
MSPMAND-CLI> show msp subs
Dumping subscriber table
Bucket index 872151 entry index 1
IP Address 2a01:1000:0:0:0:0:0:0 session count 2 svc set id 2 refcount 0 ext count 2 state 0
Plugin ID 1 refcount 0 (0xa07f969c0)
Plugin ID 8 refcount 3 (0xbe49bf070) <= Plugin ID 8 is for softwire
MSPMAND-CLI>
user@mx480-> show services sessions | refresh 300
Jun 23 14:52:36
---(refreshed at 2025-06-23 14:52:36 PDT)---
---(refreshed at 2025-06-23 14:57:37 PDT)---
---(refreshed at 2025-06-23 15:02:37 PDT)---
---(*more 100%)---[abort]
IP Address 2a01:1000:0:0:0:0:0:0 session count 0 svc set id 2 refcount 0 ext count 1 state 0
Plugin ID 8 refcount 3 (0xbe49bf070) <=Plugin ID 8 for softwire stuck forever, this is the issue
This issue is fixed thru PR1869450-some subscribers can't establish ds-lite softwire session with after after upgrade
Resolved-In
junos:22.4R3-S8 junos:23.2R2-S5 junos:23.4R2-S5 junos:23.4R2-S6 junos:24.2R2-S2 junos:24.4R2 junos:24.4R2-S2 junos:25.2R2 junos:25.3R1