Layer 4 load balancing operates at the transport layer (OSI Layer 4), using TCP/UDP protocols to distribute traffic based on information like IP addresses and port numbers, without inspecting the application-layer content (Layer 7). Let's evaluate each option:
A). Nginx: Nginx is a versatile web server and reverse proxy that supports both Layer 4 and Layer
7 load balancing. In its Layer 4 mode (e.g., with the stream module), it balances TCP/UDP traffic, making it a Layer 4 load balancing technology. This is widely used in Huawei's CloudFabric DCN solutions for traffic distribution. TRUE.
B). PPP (Point-to-Point Protocol): PPP is a Layer 2 protocol used for establishing direct connections between two nodes, typically in WAN scenarios (e.g., dial-up or VPNs). It does not perform load balancing at Layer 4 or any layer, as it's a point-to-point encapsulation protocol.
FALSE.
C). LVS (Linux Virtual Server): LVS is a high-performance, open-source load balancing solution integrated into the Linux kernel. It operates at Layer 4, using techniques like NAT, IP tunneling, or direct routing to distribute TCP/UDP traffic across backend servers. It's a core Layer 4 technology in enterprise DCNs. TRUE.
D). HAProxy: HAProxy is a high-availability load balancer that supports both Layer 4 (TCP mode) and Layer 7 (HTTP mode). In TCP mode, it balances traffic based on Layer 4 attributes, making it a Layer 4 load balancing technology. It's commonly deployed in Huawei DCN environments.
TRUE.
Thus, A (Nginx), C (LVS), and D (HAProxy) are Layer 4 load balancing technologies. PPP is not.