Catalyst 9300: StackWise-480 vs StackWise-1T vs VSS

Cisco's Catalyst 9300 family spans three different stacking architectures and it is easy to buy the wrong one. StackWise-320, StackWise-480 and StackWise-1T are not firmware options — they are hardware-dependent, they mix only under specific rules, and they deliver very different ring throughput. This article separates the three and positions them against the VSS/Virtual-style designs used elsewhere in the campus.

Which platform gets which stacking mode

• Catalyst 9300X (modular uplink) — StackWise-1T, 1 Tbps of stacking bandwidth, stacks with other 9300X at 1T and with 9300 SKUs at 480 Gbps.
• Catalyst 9300 (modular uplink) — StackWise-480, up to eight members, dedicated rear stack cables.
• Catalyst 9300L / 9300LM (fixed uplink) — StackWise-320 using the C9300L-STACK-KIT, and they cannot stack with modular-uplink models at all.

Per-ring throughput is where the difference becomes concrete: Cisco's white paper quotes 90 Gbps per ring and six rings for StackWise-1T (540 Gbps per full ring), 40 Gbps per ring and six rings for StackWise-480 (240 Gbps), and 40 Gbps per ring with four rings for StackWise-320 (160 Gbps).

Roles, SSO and NSF

A stack elects one active and one standby; every additional member is a plain member. The active and hot-standby pair synchronise state with SSO, while NSF lets the newly elected active switch keep forwarding from its last known FIB while it rebuilds control-plane state. That combination is what makes an access-stack failure a link-flap rather than an outage.

show switch
show switch stack-ports
show switch stack-ring activity
show redundancy
show switch detail

show switch stack-ports is the fast check after a cabling change — a broken ring still forwards, but traffic takes the long way round.

StackWise versus VSS and StackWise Virtual

StackWise uses dedicated rear cables and a single control plane with a distributed data plane, typically for access closets with high port density and PoE. VSS (Catalyst 4500/6500) and StackWise Virtual (Catalyst 9500/9600) create one logical switch from two chassis over regular uplinks, and they bring their own dual-active detection requirements — an EtherChannel-based fast-hello mechanism, a PAgP or BFD-based peer keepalive, and careful management of the dual-active recovery mode. If you are choosing between the two, ask whether the requirement is port density in a wiring closet (StackWise) or chassis-level redundancy at the distribution layer (VSS/StackWise Virtual).

Licensing and mixed-mode cautions

Members must run the same licence level to stack; higher-scale 9300 SKUs stack only with like models; and mixed 9300X/9300 stacks negotiate down to 480 Gbps. Plan the stack membership on paper before the hardware arrives — a stack that "works" at the wrong bandwidth is a capacity incident waiting for a busy Monday morning.

Related reading: StackWise Virtual dual-active detection, Catalyst 9000 smart licensing troubleshooting, Nexus 9300 vs 9500 platform selection.

原文链接：https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-9300-series-switches/white-paper-c11-741468.html