🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026
Affected versions: IBM AIX 7.2

📖 ~1 min read

Table of contents
  1. Symptom & Impact
  2. Environment & Reproduction
  3. Root Cause Analysis
  4. Quick Triage
  5. Step-by-Step Diagnosis
  6. Solution – Primary Fix
  7. Solution – Alternative Approaches
  8. Verification & Acceptance Criteria
  9. Rollback Plan
  10. Prevention & Hardening
  11. Related Errors & Cross-Refs
  12. References & Further Reading

Symptom & Impact

`entstat -d ent10` reports a backup adapter in `Down` state and throughput halves.

Environment & Reproduction

AIX 7.2 LPAR using SEA-backed EtherChannel ent10 with two virtual adapters.

Root Cause Analysis

One backing adapter lost link partner or VLAN tagging mismatched on the switch.

Quick Triage

Run `entstat -d ent10`, `lsattr -El ent10`, and `lsdev -Cc adapter | grep ent`.

Step-by-Step Diagnosis

Inspect VIOS `entstat -all SEA` and switch `show etherchannel summary` output.

Illustrative mockup for aix-7.2 — etherchannel_down-port_terminal
Terminal diagnostics for Etherchannel link aggregation degraded on IBM AIX 7.2 — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Refresh the channel: `/usr/sbin/cfgmgr -l ent10` after fixing switch VLAN config.

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Illustrative mockup for aix-7.2 — etherchannel_down-port_logs
Logs and evidence for Etherchannel link aggregation degraded on IBM AIX 7.2 — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Recreate ent10 with `smitty etherchannel` once the backing adapter is healthy.

Verification & Acceptance Criteria

`entstat -d ent10` shows both adapters `Up` and `Active`; throughput returns to baseline.

Rollback Plan

Detach the new adapter via `/usr/lib/methods/ethchan_config -d ent10 entX`.

Prevention & Hardening

Set LACP mode `8023ad` with `hash_mode=src_dst_port` and monitor link state with SNMP.

Related to `ENT_OTHER_EVENT` errpt and `VIO_DRIVER` warnings in NPIV mode.

Related tutorial: View the step-by-step tutorial for aix-7.2.

View all aix-7.2 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

IBM Docs: AIX EtherChannel/LACP guide, `entstat`, SEA failover tuning.

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