High Availability Approaches in Networking

Vocabulary flashcards covering key concepts from the lecture notes on high availability, redundancy, load balancing, and CDNs.

High Availability (HA)

A design approach to keep network services running with minimal downtime by using redundancy, load balancing, and scalable infrastructure.

Network Redundancy

The practice of ensuring networks stay up by creating multiple pathways and duplicate components (servers, NICs, cables, switches, routers).

Redundant Network Paths

Multiple routes between devices and to the Internet to avoid a single point of failure and enable failover.

Network Interface Card (NIC) Redundancy / NIC Teaming / Link Aggregation

Combining multiple NICs into a single logical group to provide fault tolerance and increased throughput.

Load Balancing

Distributing traffic across multiple servers or NICs to maximize performance and reliability.

Shared Load / Virtual NIC

Four NICs grouped to operate as one virtual NIC, delivering combined throughput (e.g., 4x100 Mbps = 400 Mbps).

Active-Active

A HA configuration where multiple systems run simultaneously and share load; failure of one link reduces throughput but service remains available.

Active-Passive

A HA configuration where a standby system remains idle until the primary fails; standby takes over to preserve service.

Throughput

The data transfer rate; can be increased by NIC aggregation (e.g., 2 Gbps with two 1 Gbps links).

Switches and Routers Redundancy

Configuring multiple trunk ports and cables so a switch can be serviced by more than one router, with failover.

Fiber Optic Trunk Ports

Using fiber cables on trunk ports to provide high-speed, redundant connections between network devices.

Content Delivery Network (CDN)

A geographically distributed network of servers that caches content closer to users to reduce latency and reroute traffic during failures.

Load Balancer

A device or service that distributes incoming traffic across multiple servers, monitors health, and reroutes around failed nodes.

Always-On Battery Backup (UPS)

Uninterruptible power supply system that stores energy and keeps critical systems running during outages; can provide power for extended periods depending on size.

Power Redundancy: Active-Active vs Active-Passive

Active-Active uses multiple power sources simultaneously to supply loads at all times; Active-Passive uses a standby source that only activates on failure.