Data Centre - Definition
A facility housing computer systems and components, including servers, storage systems, and networking equipment.
Data Centre - Purpose
Provides centralized data storage, processing, and dissemination services for organizations.
Data Centre - Importance
Essential for supporting web services, cloud computing, and large-scale computational tasks.
Data Centre - Historical Context
Data centres have evolved from simple server rooms to complex facilities.
Data Centre - Key drivers
Demand for large-scale computing services.
Applications in web search, online social networks, and scientific computations.
Data Centre - Challenges
Increasing resource requirements.
Bottlenecks in inter-node communication bandwidth.
Majority of traffic is internal within the Data Centre Network (DCN).
Data Centre Networking Basics - Components
Servers: Transition from high-end enterprise servers to low-cost, large-scale server deployments.
Networking Infrastructure: Needs to support extensive inter-server communication.
Data Centre Networking Basics - Trends
Shift towards commoditization using large numbers of affordable servers.
Aggregate reliability mitigates individual server vulnerability.
Data Centre Networking Basics - Networking Challenges
Traditional enterprise solutions are insufficient for large-scale needs.
Movement towards scalable, commodity-based networking components.
Desirable Features for Data Centre Networks
Support for a large number of servers (100k+ hosts).
High capacity and bandwidth between servers.
Full access to resource pools with flexible network allocation.
High utilization and reliability.
Backward compatibility and energy efficiency.
Scalability and cost-effectiveness.
High Performance Computing (HPC)
Designed for applications requiring significant computational power.
Examples: Financial systems and scientific computing utilizing technologies like InfiniBand and Myrinet.
High Performance Computing (HPC) - Advantages
High bandwidth and low latency.
Simple setup and low maintenance complexity.
High Performance Computing (HPC) - Disadvantages
High costs due to non-commodity equipment.
Incompatibility with TCP/IP applications.
Networking Approach
Utilizes off-the-shelf networking equipment such as Ethernet networks.
Networking Approach - Advancements
Switches with more ports and higher bandwidth capabilities.
Leverages ongoing technology improvements for cost-effective solutions.
Networking Approach - Pros
Cost-effective and backward-compatible.
Networking Approach - Cons
Challenges in building scalable and efficient Data Centre Networks (DCNs).
Conventional Data Centre Networks Architecture - Structure
Commodity servers and networking elements arranged in racks.
Conventional Data Centre Networks Architecture - Topologies
Top-of-Rack (ToR): Network switches located on top of server racks.
End-of-Row (EoR): Centralized switching for entire rows of racks.
Conventional Data Centre Networks Architecture - Architecture Levels
Core: High-level routing and backbone connectivity.
Aggregation: Intermediate layer connecting core and access levels.
Access/Edge: Connects directly to servers and devices.
Data Centre Networks Issues - Challenge in Conventional Architectures
Resource Fragmentation: Inefficient resource allocation across the network.
Server-to-Server Bandwidth: Limited by high oversubscription ratios (few:1 to hundreds:1).
Service Isolation: Difficulties in segregating services within shared environments.
TCP Incast Problem: Network congestion due to simultaneous data requests from multiple servers.
Fat Tree Concept - Core Idea
Balances uplink and downlink bandwidths, creating a non-blocking and non-interfering network
Fat Tree Concept - Architecture
Hierarchical network design resembling a tree structure, expanding bandwidth as it ascends.
Fat Tree Concept - Features
Equal uplink and downlink bandwidth.
Scalable and flexible design, suitable for large-scale data centers.
