Networking · Cluster
Network Operations
Diagnosis, configuration, and failure recovery.
- 01 Interface Configuration Order: Link State, Address Assignment, and Route Installation Why an interface can hold a valid address and still be unreachable, how duplicate address detection suspends usability, and which piece of state to inspect first.
- 02 Where a Packet Capture Sits Determines What It Shows How capture points on hosts, bridges, and taps differ in what they observe, and why segmentation offload and checksum offload make a local capture disagree with the wire.
- 03 Interface Drop Counters and What Each One Actually Attributes How kernels classify discarded packets into drop, error, and overrun counters, and why a clean counter set can coexist with a link that loses traffic.
- 04 Neighbour Cache Staleness and Peers That Become Unreachable How ARP and Neighbor Discovery entries age through reachable, stale, and probe states, and why a stale entry keeps sending traffic to an address that has moved.
- 05 Confirmed Commit and Automatic Rollback for Remote Configuration Changes How a candidate datastore plus a confirm timer bounds the damage from a configuration change that severs the connection used to make it, and where the mechanism fails.
- 06 Correlating Logs Across Devices When Clocks Disagree How clock offset and resolution error bound the accuracy of a merged timeline, and how to order events from independent devices without trusting their timestamps.
- 07 Link Aggregation Member Selection and the Mismatches That Stall It How frames are hashed onto bundle members, why a single flow cannot exceed one link, and which LACP negotiation failures leave a bundle passing some traffic.
- 08 Reading a BGP Session Failure From Its State and Its Last Error How the session states narrow a failure to transport, capability negotiation, or policy, and why a session that reaches Established can still exchange no routes.
- 09 Flow Sampling Error When Deciding Whether a Link Is Full How sampled flow records estimate volume, why small conversations disappear entirely, and how to tell sampling noise from a real change in traffic mix.
- 10 Draining a Router for Maintenance Without Dropping In-Flight Traffic How to withdraw a router from the forwarding path by changing what the control plane advertises, how long convergence takes, and why the drain interval must exceed it.