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PASSEDvendor / juniper_mx_bgp_session_flap
Juniper MX Router BGP Session Flap
A Juniper MX480 border router experiences BGP session flapping with two upstream ISPs due to a line card memory error, causing route oscillation and intermittent internet connectivity for the entire organization.
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 | 29 linked | |
| Cascade Escalation | Yes | Yes | |
| Remediation | — | Remote Hands — Corax contacts on-site support via call, email, or API |
Scenario Conditions
Juniper MX480 as border router. Two eBGP sessions to upstream ISPs. Line card MPC7E memory parity error. BGP sessions flapping every 2-5 minutes. Full routing table (950K+ routes). 2000 users affected.
Injected Error Messages (3)
juniper MX480 BGP session instability — eBGP session to ISP-A (AS64501) flapping every 2-5 minutes, juniper line card MPC7E-MRATE reporting memory parity errors, BGP NOTIFICATION sent: hold timer expired, route table oscillation affecting 950000 prefixes, juniper rpd process consuming high resources during reconvergence
juniper MX480 eBGP peer 203.0.113.1 (ISP-A) session down — juniper BGP state: idle, last flap 2 minutes ago, BGP session has flapped 18 times in last hour, juniper routing engine receiving correctable memory errors from FPC slot 2, route dampening not configured, full internet routing table reconverging on each flap
intermittent internet outage caused by juniper MX480 BGP route oscillation — upstream BGP sessions cycling between established and idle states, juniper border router losing and re-learning 950K routes every 2-5 minutes, internet unreachable during convergence windows of 30-90 seconds per flap event
Neural Engine Root Cause Analysis
The Juniper MX480 border router is experiencing a cascade failure initiated by hardware issues on the MPC7E-MRATE line card reporting memory parity errors. These memory errors are causing instability in the RPD (Routing Protocol Daemon) process, leading to resource exhaustion and BGP session instability with ISP-A (AS64501). The BGP session flapping every 2-5 minutes is triggering hold timer expirations and causing massive route table oscillation affecting 950,000 prefixes, which explains the 12 correlated incidents occurring simultaneously.
Remediation Plan
1. Immediately contact ISP-A to coordinate traffic engineering and potentially activate backup paths. 2. Access Juniper MX480 CLI and disable the failing MPC7E-MRATE line card to prevent further memory parity errors. 3. Restart the RPD process to clear resource consumption issues. 4. Monitor BGP session stability and route convergence. 5. If BGP stabilizes, gradually re-enable traffic flows. 6. Schedule emergency hardware replacement for the faulty line card. 7. Implement temporary route filtering to reduce convergence impact if needed.
Tested: 2026-03-30Monitors: 3 | Incidents: 3Test ID: cmnck5lwh06wjobqeqyvjpocs