Back to All Scenarios
PASSEDvendor / juniper_ex_virtual_chassis_split
Juniper EX Switch Virtual Chassis Split
A Juniper EX4300 virtual chassis of 4 members splits into two partitions when a VCP cable is severed during cable management, causing half the access ports to lose their trunk uplinks.
Pattern
UNKNOWN
Severity
CRITICAL
Confidence
85%
Remediation
Remote Hands
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | UNKNOWN | UNKNOWN | |
| Severity Assessment | CRITICAL | CRITICAL | |
| Incident Correlation | Yes | 21 linked | |
| Cascade Escalation | N/A | No | |
| Remediation | — | Remote Hands — Corax contacts on-site support via call, email, or API |
Scenario Conditions
Juniper EX4300-48T virtual chassis, 4 members in ring topology. VCP cable between member 1 and member 2 severed. VC splits into two 2-member partitions. 96 access ports isolated.
Injected Error Messages (2)
juniper EX4300 virtual chassis split detected — VC member 1 lost VCP adjacency to member 2, juniper virtual chassis partitioned into two segments: members 0-1 and members 2-3, VC ring topology broken, juniper mastership re-election in partition 2, 96 access ports on members 2-3 lost uplink connectivity to core
juniper EX4300 virtual chassis partition — member 2 elected as master of secondary partition, juniper VC split causing duplicate management IPs, members 2-3 operating independently with stale configuration, inter-member trunk links severed, 96 ports in isolated partition with no routing to rest of network
Neural Engine Root Cause Analysis
The Juniper EX4300 Virtual Chassis has experienced a split-brain condition where the Virtual Chassis Port (VCP) connection between member 1 and member 2 has failed, causing the 4-member VC to partition into two segments (0-1 and 2-3). This breaks the ring topology essential for VC operation and triggers mastership re-election in partition 2. The failure of the VCP interconnect is likely due to physical cable failure, port malfunction, or transceiver issues on the stacking cables between switches 1 and 2.
Remediation Plan
1. Immediately verify physical VCP cable connections between VC members 1 and 2, check for loose connections or damaged stacking cables. 2. Examine VCP port status and statistics on both members using 'show virtual-chassis status' and 'show virtual-chassis vc-port'. 3. If cables appear intact, swap VCP cables or try alternate VCP ports if available. 4. Check for transceiver failures and replace if necessary. 5. If hardware replacement is required, consider temporary network reconfiguration to restore connectivity to the 96 affected access ports. 6. Once VCP connectivity is restored, monitor VC convergence and verify all members rejoin properly.
Tested: 2026-03-30Monitors: 2 | Incidents: 2Test ID: cmnck5l3806wiobqei8lvwcpw