Data Center Networking

Network Architecture and Design

Data center networking begins with the selection of a network architecture. Two common choices are:

1. Three-Tier Architecture - This architecture utilizes three layers of network switches: a core layer that provides network transmission, a distribution layer that aggregates and distributes traffic between layers, and an access layer that connects to storage devices and servers in the data center. 
2. Two-Tier/Spine-Leaf Architecture - This architecture utilizes two layers of network switches: a spine layer that functions as the network’s core and handles packet routing, and a leaf layer consisting of numerous access switches that connect to storage and servers in the data center. Every access switch in the leaf layer is directly connected to every core switch in the spine layer, ensuring consistent, low-latency data transfer between servers in the data center.

Spine-leaf architectures are the most common choice for modern data centers based on their improved scalability, redundancy, and low latency when transferring data between servers hosted in the same data center.

After choosing a network architecture, the next step is to design the network. A network architect draws or builds a network diagram to illustrate the physical, virtual, and logical organization of network devices and IT infrastructure that will power the network.

Physical Network Infrastructure

After deciding on a network architecture and designing the network, the next step is to build the network by implementing and configuring physical network infrastructure. This includes physical network devices like:

• Switches - Switches connect devices inside the network and allow those devices to communicate by exchanging data packets between them.
• Routers - Routers are network devices that connect different networks together and determine the best path for data transfer between those networks. Routers in a data center are used to connect the internal data center network with external networks, such as the public Internet.
• Firewalls - Firewalls monitor and control traffic at the network perimeter based on defined security rules, protecting against unauthorized data access and blocking cyber attacks against the network.
• Load Balancers - Load balancers distribute incoming network traffic across multiple servers to prevent individual servers from being overwhelmed by traffic spikes.
• Gateways - Gateways serve as network entry/exit points where network traffic may be translated from one communication protocol to another. There are multiple types of gateways, including VPN gateways that enable remote network access and cloud gateways that connect the data center with public cloud services.
• Cabling - Copper cabling may be used for short-distance connections, but fiber optic cabling is best for enabling high-bandwidth connections between devices, even over long distances.

Virtualization and SDNs

Data center operators can use virtualization technology to create multiple virtual networks on the same physical infrastructure, a strategy that allows for multiple tenants with their own private networks on the same physical servers.

Software-defined networks are also frequently implemented to abstract the network control plane away from the underlying physical infrastructure and enable centralized network control and automation.

External Connectivity

Once the internal data center network has been established, the next step for data center operators is to establish connections with external services. This includes:

• Internet Connectivity - Connecting the data center with the Internet enables public access to applications, websites, and other services hosted on servers inside the data center.
• Cloud Connectivity - Direct cloud connectivity enabling high-performance hybrid cloud architectures and ensures consistent low-latency data transfer.
• Data Center Interconnection - Connecting the data center with other data centers in different locations supports use cases like data back-up, disaster recovery, and load balancing.

Network Infrastructure Monitoring

Data center operators use network infrastructure monitoring software tools to track and manage the availability, performance, and security status of their network infrastructure. Network infrastructure monitoring allows data center operators to:

• Proactively identify and remediate network performance issues or traffic bottlenecks to avoid slowdowns and optimize end-user experiences.
• Proactively identify and remediate security threats against the network to prevent data breaches and avoid unplanned operational downtime.
• Proactively detect service outages or hardware failures and rapidly initiate disaster recovery protocols to safeguard customer operations.
• Efficiently manage network resources and reduce costs.

Network Automation and Orchestration

Data center engineers and technicians often implement automation technologies to streamline the process of configuring, managing, and operating networks in the data center. Automation can help with tasks like:

• Configuration Management - Automatically updating or applying configuration settings to network devices based on predefined policies.
• Resource Provisioning - Automating the allocation of storage, compute, network, or virtualization resources based on customer requests.
• Security - Data center SOC teams use automation to monitor the network for Indicators of Compromise (IoCs), scan networks for emerging vulnerabilities, enforce security policies and audit compliance with legal requirements.

Network orchestration technology is also used to coordinate service delivery across multiple applications and automate workflows.