Packet Buffer Reference

FS Trident 3 Series (N5570 / N5850 / N8550 / N8560)

FS produces six Trident 3-based switch platforms covering access (10G/25G ToR) through spine (100G) deployments. All share the 32 MB unified shared buffer of the Broadcom Trident 3 ASIC.

Models

Model ASIC Ports Capacity Buffer
N5570-48S6C BCM56771 (Trident 3 X5) 48x 10G SFP+, 6x 100G QSFP28 1.08 Tbps 32 MB
N5850-48X6C BCM56771 (Trident 3 X5) 48x 10G RJ45, 6x 100G QSFP28 1.08 Tbps 32 MB
N8550-32C BCM56870 (Trident 3 X7) 32x 100G QSFP28, 2x 10G SFP+ 3.2 Tbps 32 MB
N8550-48B8C BCM56873 (Trident 3) 48x 25G SFP28, 8x 100G QSFP28, 2x 10G SFP+ 2.0 Tbps 32 MB
N8560-32C BCM56870 (Trident 3 X7) 32x 100G QSFP28, 2x 10G SFP+ 3.2 Tbps 32 MB
N8560-48BC BCM56873 (Trident 3) 48x 25G SFP28, 8x 100G QSFP28, 2x 10G SFP+ 2.0 Tbps 32 MB

The N8550 and N8560 lines target the same roles (spine/leaf at 100G and 25G) but the N8560 is a newer platform generation with updated hardware design.

Buffer Architecture

All six switches use Broadcom's 32 MB unified on-chip SRAM introduced with Trident 3. Unlike the segmented per-pipe buffer of the original Tomahawk, the entire 32 MB pool is accessible to all ports simultaneously under the control of a centralized MMU. Dynamic thresholding allows congested ports and queues to claim memory from the shared pool up to configurable maximums.

The X5-tier chips (BCM56771, used in N5570/N5850 access platforms) carry the same 32 MB buffer as the X7-tier BCM56870 — the difference is switching bandwidth (2.0 Tbps vs. 3.2 Tbps), not buffer capacity.

8 traffic classes (queues) are supported per port. The FleXGS programmable pipeline supports P4-influenced custom forwarding, and BroadView Gen3 telemetry enables real-time microburst visibility.

References

See Also