Exploring Redundant Connections For Reliability In Data Center Environments

Data centers play a key role in modern business operations. It’s therefore vital for them to operate reliably. To minimize the potential for disruptions, data centers are designed to be highly resilient. In particular, they implement high levels of redundancy. Here is a quick guide to what you need to know about leveraging redundancy in data centers.

Understanding redundant connections

Redundant network connections are backup pathways that ensure continuous network connectivity and data transmission in the event of a primary network failure. There are generally two parts to redundant network connections in data centers. These are physical redundancy and logical redundancy.

Physical redundancy

Physical redundancy in network connectivity refers to the use of multiple physical components to create backup pathways for data transmission. In data centers, this involves duplicating hardware such as cables, switches, routers, and network interfaces to ensure that if one component fails, another can immediately take over.

Logical redundancy

Logical redundancy involves creating multiple logical pathways for data over the same or overlapping physical infrastructure. This type of redundancy is achieved through network protocols and software configurations that enable data to be rerouted automatically in case of a failure.

Ways to implement physical redundancy in data center networks

Here is an overview of five of the main ways to implement physical redundancy in data center networks.

Dual power supplies

Implementing dual power supplies involves equipping servers and network devices with two independent power units. Each power supply is connected to a different power source, ensuring that if one power source fails, the other can immediately take over. By distributing the power load between the two supplies, the system also enhances efficiency and extends the lifespan of the power units.

Redundant network interface cards (NICs)

Redundant Network Interface Cards (NICs) provide multiple physical network connections for a single server or device. Each NIC connects to different network switches, offering an alternative path for data if one NIC or switch fails. This setup enhances network reliability by ensuring that the server remains connected even during hardware malfunctions.

Dual cabling

Dual cabling involves running two separate network cables from a device to different network switches or routers. These cables follow diverse physical paths to avoid single points of failure, such as accidental cuts or hardware issues. This method ensures that if one cable is damaged, the other can continue to carry the data traffic.

Redundant switches and routers

Using redundant switches and routers means deploying multiple, identical network devices to handle the same traffic load. These devices are typically set up in parallel, with each connected to different network segments. Redundancy protocols like HSRP (Hot Standby Router Protocol) or VRRP (Virtual Router Redundancy Protocol) can be used to manage failover processes.

Diverse path routing

Diverse path routing involves setting up multiple physical paths for network traffic between endpoints within the data center. This can be achieved by connecting devices through different physical routes that do not overlap, reducing the risk of a single point of failure affecting connectivity.

Ways to implement logical redundancy in data center networks

Here is an overview of five of the main ways to implement logical redundancy in data center networks.

Routing protocols (OSPF/BGP)

Implementing routing protocols like OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol) ensures logical redundancy by dynamically managing and rerouting traffic in case of link or device failures.

OSPF is used within an autonomous system (intra-domain) and quickly adapts to changes in the network topology, recalculating the shortest path for data packets. BGP manages routing between different autonomous systems (inter-domain), ensuring continuous connectivity even if some external paths fail.

Link aggregation (LACP)

Link Aggregation Control Protocol (LACP) combines multiple physical links into a single logical link to increase bandwidth and provide redundancy. If one link in the aggregation group fails, LACP automatically redistributes the traffic across the remaining links, ensuring uninterrupted data transmission.

Virtual LANs (VLANs)

VLANs (Virtual Local Area Networks) create logically segmented networks within the same physical infrastructure, isolating traffic for security and performance purposes. By configuring multiple VLANs, network administrators can ensure that a failure in one VLAN does not affect the others, thus providing logical redundancy.

Spanning tree protocol (STP)

Spanning Tree Protocol (STP) is designed to prevent network loops in Ethernet networks by creating a loop-free logical topology. STP detects and disables redundant paths in the network, placing them in a standby state. If an active path fails, STP reactivates the redundant paths, allowing traffic to reroute through these alternative links.

Load balancers

Load balancers distribute network traffic across multiple servers or network paths, ensuring even load distribution and redundancy. By monitoring the health of servers and network paths, load balancers can detect failures and reroute traffic to healthy nodes, preventing service interruptions.