Describes how the ACI architecture addresses traditional data center design limitations by supporting increased east-west traffic demands and utilizing a spine-leaf topology to improve network efficiency.
The ACI architecture is a spine-leaf network design that optimizes modern data center traffic by decoupling Layer 2 domains from the underlying Layer 3 infrastructure using VXLAN.
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Supports increased east-west traffic demands driven by modern application designs.
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Provides a single switch abstraction for bridging and routing capabilities.
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Enables Layer 2 adjacency for virtual machine mobility and clustering software across the fabric.
Traffic Flow and Fabric Architecture
Traditional data center designs rely on north-south traffic patterns and Spanning Tree Protocol, which often results in blocked links and suboptimal paths. The ACI fabric improves upon these designs through the following mechanisms:
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Encapsulation and policy application at the fabric entry point.
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Forwarding across the fabric through a spine switch with a maximum of two hops.
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Utilization of IS-IS and COOP for endpoint-to-endpoint communication.
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Implementation of MP-BGP for propagating routing information between software-defined networks and external routers.
The following figure illustrates the ACI fabric architecture.
