Cisco NX-OS provides switching fabric availability through redundant switch fabric module implementation. You can configure a single Cisco Nexus 9504, 9508, or 9516 chassis with one to six switch fabric modules for capacity and redundancy. Each line card installed in the system automatically connects to and uses all functionally installed switch fabric modules. A failure of a switch fabric module triggers an automatic reallocation and balancing of traffic across the remaining active switch fabric modules. Replacing the failed fabric module reverses this process. After you insert the replacement fabric module and bring it online, traffic is again redistributed across all installed fabric modules and redundancy is restored.
Fabric modules are hot swappable. Hot swapping can temporarily disrupt traffic. To prevent the disruption of traffic when you hot-swap fabric modules, use the poweroff module slot-number command before you remove a fabric module and the no poweroff module slot-number command after you reinsert the fabric module.
To get line rate traffic with X9464PX, X9464TX, and X9432PQ line cards, you must insert four fabric modules into four fabric module slots (FM2, FM3, FM4, and FM6). Additional fabric modules will not provide additional redundancy for these line cards.
To get line rate traffic with X9564PX, X9564TX, and X9536PQ line cards, you must insert three fabric modules into the even fabric module slots (FM2, FM4, and FM6). Additional fabric modules will provide additional redundancy for these line cards. Each even fabric module provides redundancy for each odd fabric module failure (FM2 provides redundancy for FM1, FM4 provides redundancy for FM3, and FM6 provides redundancy for FM5).
To get line rate traffic with X9636PQ line cards, you must insert all six fabric modules. This line card is supported only in the 4-slot and 8-slot Cisco Nexus 9500 Series chassis.
Fabric modules with the network forwarding engine (NFE) can operate in two modes: full-rate mode (FRM) or oversubscribed mode (OSM). In OSM, all 32 40G ports are enabled on the NFE for a total I/O bandwidth of 1280G. In FRM, only 24 ports are enabled on the NFE for a total bandwidth of 960G at all packet sizes. In OSM, the NFE cannot run at line rate for a packet size of less than 200 bytes.
Fabric module NFEs run in FRM for Cisco NX-OS Releases 6.1(2)I1(x), 6.1(2)I2(1), and 6.1(2)I2(2). Starting with Cisco NX-OS Release 6.1(2)I2(2a), fabric module NFEs can run in FRM or OSM, but OSM is the default mode.
Some line cards cannot be powered up when the system fabric is operating in FRM. This table lists the line card types that are supported in each mode:
Operating Mode
Supported Line Cards
OSM
Allows a mix of all three line card types (X9400, X9500, X9600)
FRM
Allows a mix of X9500 and X9600 line cards (excluding the X9536PQ)
