what is the difference between Cisco FI and Cisco SAN

[Abhinav]

I have a question, what is the difference or application of the fiber interconnect switch FI (FI 6454) and SAN switch (MDS 9148). I understand that San uses it for fast switching of larger data between server and storage. Then why the FI for? Like FI6454 etc. I always seen hyperflex system are connected to FI switches and then from FI to MDS and MDS connects to Storage. Also, TOR is connected to further DC CORE. here why is the FI required and what is its purpose, can't the Hyperflex directly connect to SAN and SAN to storage?  Also, if we are using the iSCSI the san and FI is that really required? of just a nexus can do the JOB over ethernet.

[marce1000]

  - Ref : https://www.cisco.com/c/dam/en/us/solutions/collateral/enterprise-networks/enterprise-network-security/data-center-design-playbook.pdf
               Look at the mentioned components with find in the browser , then explore the right summary pane to explore differences ,

 M.

[M02@rt37 · Accepted solution]

Hello @Abhinav 

The FI plays a crucial role in Cisco's UCS and HyperFlex environments by acting as a central hub for managing and aggregating both networking and storage connections from servers. The FI consolidates Ethernet and FCoE traffic, providing a single point of management for server profiles, LAN, and SAN connectivity. This simplifies the overall infrastructure by reducing cabling complexity and ensuring consistent network configurations across all connected servers. In a HyperFlex setup, the FI facilitates the connection between the compute nodes and the upstream network, including both the LAN (through top-of-rack or core switches) and the SAN (through a SAN switch), which is essential for unified management and efficient resource allocation.

On the other hand, a SAN switch like the Cisco MDS9148 is designed specifically for high-performance, low-latency Fibre Channel networks, managing the dedicated storage traffic between servers (often through FIs) and storage arrays. The SAN switch ensures fast, secure, and reliable communication within the storage network, providing zoning and other storage-specific management features. While HyperFlex nodes could theoretically connect directly to a SAN switch, this would bypass the centralized management benefits of the FI, leading to more complex configurations and potentially inconsistent network setups. Even in environments using iSCSI, where storage traffic runs over Ethernet, the FI remains valuable for its role in aggregating and managing server connections, ensuring a streamlined, scalable infrastructure.