Network Products by Layer
L1 Physical
Circuits, ports, facilities and points of presence. There is almost no programmability here — what you compare is carrier coverage, rack specs and CPE hardware.
L2 Data Link
Layer 2 in the cloud is mostly 'virtualized away': the VPC emulates L2 with a VXLAN overlay while banning broadcast flooding, MAC spoofing and promiscuous mode.
L3 Network
The densest layer for network products: addressing, routing, inter-network connectivity, internet ingress/egress and L3 firewalling are all decided here — and it shows the 'many vendors per capability' pattern most clearly.
L4 Transport
Forwarding and permitting by port and connection: L4 load balancing, security groups and port mapping live here, and it is the most competitive layer for load balancer vendors.
L5 Session
In cloud products L5 is rarely a standalone product — it shows up as session persistence, remote access and long-lived connection handling, and remote access is steadily being replaced by ZTNA.
L6 Presentation
Encryption, certificates, compression and encoding — in cloud this mostly means certificate and key management plus TLS termination on gateways, and vendor choice is driven largely by compliance and trust requirements.
L7 Application
The layer that understands business semantics: name resolution, L7 routing, canary releases, rate limiting, authentication and web attack protection — and the most fiercely contested market for security and CDN vendors.
Cross-layer · Management & Observability
Not part of any single layer, but it decides whether you can see what is happening in all of them — the working surface for troubleshooting and operations, and a stronghold for third-party SaaS vendors.