Round Robin and Least Connection were the standard load balancer choices for years. Yet the core algorithm that modern LBs like Envoy and AWS ALB ship as their headline option is Least Outstanding Requests, and its practical implementation is Power of Two Choices. This post traces the evolution path along which the unit of routing decisions moved from connection to request.
Isolation, routing, connectivity, security — VPC’s four axes pulled into one place, framed around the decisions backend engineers actually face.
Three practical topics for operating TLS on top of the basic handshake. Session resumption and 0-RTT cut the repeated cost, mTLS authenticates the client too, and ACME automates certificate issuance and renewal.
TLS builds a secure channel over an untrusted network by providing confidentiality, integrity, and authentication. A walkthrough of symmetric/asymmetric hybrid encryption, the TLS 1.2 handshake, the certificate and PKI trust model, and what TLS 1.3 improved.
HTTP/1.1 processes requests and responses sequentially. HTTP/2 changed this with multiplexing, binary framing, and header compression. A summary of the differences between the two protocols and gRPC, which runs on HTTP/2.
Two transport protocols that backend developers encounter constantly. A summary of TCP and UDP — connection establishment, reliability guarantees, flow/congestion control mechanisms, and selection criteria.
L2 switch, L3 routing, L4/L7 load balancer — where the layer numbers attached to everyday networking terms come from. How the OSI model maps to TCP/IP, and what each number refers to.