Mobile Computing · Cluster
Mobile Networking
Radio state, offline behavior, and retries.
- 01 Radio Resource Control States and the Tail Timer After the Last Byte Why a cellular radio stays powered for seconds after a transfer ends, what each connection state costs, and how the spacing of requests decides which transitions are paid.
- 02 What a Connectivity Callback Reports and What It Cannot Why the operating system reports a network as available before it can reach anything, and which checks distinguish a captive portal from an outage from a broken name lookup.
- 03 Counting Round Trips Before the First Payload Byte A cold request on a phone crosses radio setup, name resolution, a transport handshake, and a TLS handshake before any application data moves, and each layer can be shortened.
- 04 Retry Classification When the Failure Arrives as a Timeout A timeout is the absence of an answer, not a statement that the request failed, and the decision to retry depends on whether the server can tell a duplicate from a first attempt.
- 05 The Durable Outbox: Committing Locally Before the Network Agrees How an app records an intended write on disk, drains it in order, and survives process death, so that a user action is never lost to a failed request.
- 06 Replaying a Queue Against State That Has Moved On When queued writes finally reach the server, the world may have changed beneath them; version vectors, field-level merge rules, and conflict surfacing decide what survives.
- 07 Push Notification as a Store-and-Forward Channel Why mobile push cannot be a socket the server writes to, how the vendor service buffers and delivers, and what the delivery guarantees do and do not include.
- 08 Open Connections When the Device Changes Its Address A handover replaces the address under a live socket; why TCP cannot follow it, how QUIC connection identifiers and path validation allow migration, and what a rebinding costs.
- 09 Radio Tail Energy and the Cost of the Second Request Energy per byte is not a constant on a cellular radio; it depends on how long the radio stays powered, which makes request spacing a first-order energy decision.
- 10 Retry Storms When a Network Comes Back Recovery is harder than outage: every queued client retries at once, and the mechanisms that keep a system stable are jitter, admission control, and a drain rate the server can sustain.