This article is to report a behavior difference noticed with SNMP polling in case of RTG when EX4300 switches are running JUNOS beyond 21.4R3-S6
When SNMP polling is done for oid 1.3.6.1.2.1.17.7.1.4.5.1 with redundant-trunk-group interfaces configured and EX4300 switch is running Junos version 21.4R3-S6 and above, there will be L2ALD memory leak seen on the switch. It can be verified using command:
show ethernet-switching debug-statistics memory | match l2ald_mib_dot1dTp_lookup
---(refreshed at 2025-09-03 20:28:30 IST)---
Allocated Allocated Allocated Memory
(current) (total) (freed) (owner)
6532 450708 444176 [l2ald_mib_dot1dTp_lookup (0x1bd9f60)]
---(refreshed at 2025-09-03 20:28:35 IST)---
6856 473064 466208 [l2ald_mib_dot1dTp_lookup (0x1bd9f60)]
---(refreshed at 2025-09-03 20:28:40 IST)---
7280 502320 495040 [l2ald_mib_dot1dTp_lookup (0x1bd9f60)]
External-Trigger
After Upgrading from 21.4R3-S3.4 to 21.4R3-S6 Junos version and above with RTG interfaces configured:
set interfaces ge-0/0/8 ether-options 802.3ad ae0
set interfaces ge-0/0/18 ether-options 802.3ad ae1
set switch-options redundant-trunk-group group rtg0 interface ae0.0
set switch-options redundant-trunk-group group rtg0 interface ae1.0
set interfaces ae0 unit 0 family ethernet-switching vlan members v100
set interfaces ae1 unit 0 family ethernet-switching vlan members v100
Set vlans v100 vlan-id 100
SNMP polling for OID 1.3.6.1.2.1.17.7.1.4.5.1 causes a l2ALD memory leak
Ex: show snmp mib walk 1.3.6.1.2.1.17.7.1.4.5.1
Solution is provided as fix of PR1892944.
Workaround:
Excluding the oid 1.3.6.1.2.1.17.7.1.4.5.1 from snmp polling would prevent the L2ALD leak from happening
R1# show |compare
[edit snmp view all]
oid .1 { ... }
+ oid 1.3.6.1.2.1.17.7.1.4.5.1 exclude;