DCII: Cisco FabricPath Overview

Cisco FabricPath Overview:
• Why? STP problems: blocks certain ports to ensure a loop-free network ➡️ unused bandwidth, not necessarily optimal forwarding path for all traffic
• How? Replace STP with [L2] IS-IS (separate process from L3 IS-IS) ➡️ no blocked ports + ECMP

Cisco FabricPath Header:
• FabricPath uses MAC-in-MAC encapsulation
• switches encapsulate Ethernet frames using FabricPath headers
• contains 48-bit outer SA, 48-bit outer DA, and 32-bit Cisco FabricPath tag