A fixed switch whose main ports are 100G or 400G is a different buy from a 10G leaf or a campus aggregation PID. Port faceplate comes first. Brand comes second.
Buyer rule: if servers are still 10G or 25G, stop. Use a leaf buying guide instead. This article is only for fixed platforms whose working ports are 100G or 400G.
What “fixed 100G / 400G class” actually means
On these PIDs the switch itself is the high-speed platform. You are not buying a 48 × 10G leaf that happens to have a few 100G uplinks. CE8850-32CQ-EI, RG-S6520-64CQ, and RG-S6580-48CQ8QC put 100G (and on one PID, 400G) on the working faceplate.
- Fabric / spine leaning: when most ports face other switches or dense 100G/400G links.
- High-density leaf leaning: when most ports face 100G servers or storage NICs.
- Not this class: S6805-54HF (48 × 10GE + 6 × 100GE) stays on a 10G leaf shortlist.
Three faceplates, three jobs
| Need | Start from | Faceplate | Listed capacity | Forwarding |
|---|---|---|---|---|
| About 32 × 100G | CE8850-32CQ-EI | 32 × 100GE QSFP28 + 2 × 10GE | 6.4 Tbps | 3,200 Mpps |
| Full 64 × 100G | RG-S6520-64CQ | 64 × 100GE QSFP28 | 12.8 Tbps | 4482 Mpps |
| 100G plus 400G | RG-S6580-48CQ8QC | 48 × 100GE DSFP + 8 × 400GE | 16.0 Tbps | 5350 Mpps |
CE8850-32CQ-EI
32 × 100GE QSFP28 + 2 × 10GE
6.4 Tbps · 3,200 Mpps
Start here when about 32 × 100G is enough and 400G is not required.
RG-S6520-64CQ
64 × 100GE QSFP28
12.8 Tbps · 4482 Mpps
Start here when every port is 100G and density must be 64.
RG-S6580-48CQ8QC
48 × 100GE DSFP + 8 × 400GE
16.0 Tbps · 5350 Mpps
Start here only when 400G ports are in the optic plan.
Faceplate planning before optics
Count the ports you will light on day one, then the ports you must reserve for the next known expansion. Do not buy 64 × 100G because the Tbps number looks larger if only twenty ports will ever be used.
Faceplate checklist
- How many 100G ports are lit on day one?
- How many 400G ports are required on day one?
- Will any QSFP28 port be broken out, and to what?
- Do you need the two 10G ports on CE8850-32CQ-EI?
- Is airflow front-to-back or back-to-front in this rack?
Optics, breakout, and usable design
Capacity and forwarding on the datasheet are not a substitute for an optic map. QSFP28 and QSFP-DD SKUs, reach, and breakout must be written on the RFQ. Breakout is only “supported” when the optic, the software train, and the peer device agree — ask for confirmation rather than assuming a brochure line.
| Decision | What to put on the RFQ |
|---|---|
| 100G only | QSFP28 optic type + reach + quantity per PID |
| 400G ports | QSFP-DD optic type + how many of the eight ports will be lit |
| Breakout | Exact breakout mode and peer NIC/switch PID |
| 10G adjunct | Whether CE8850’s 2 × 10GE SFP+ are in use |
Capacity vs usable requirement
6.4 Tbps, 12.8 Tbps, and 16.0 Tbps are not interchangeable scores. A design that never lights 400G gains nothing from the 16.0 Tbps figure on RG-S6580-48CQ8QC. A design that needs sixty-four 100G ports is a poor fit for a 32-port faceplate even if forwarding Mpps looks fine on paper.
Redundancy, airflow, power, rack
- PSU: both Ruijie PIDs list 1+1 hot-swap; CE8850 lists dual hot-swap — still confirm AC/DC and airflow with sales.
- Rack: RG-S6520-64CQ authorized data is 2U class (~88.1 mm). RG-S6580-48CQ8QC authorized data is 1U height with a deep chassis — confirm rail depth.
- Weight: plan roughly 9 kg (CE8850 class), ~20 kg (64CQ), ~16 kg (48CQ8QC) from authorized listings, then verify on the datasheet attached to the quote.
Migration from 100G toward 400G
If the fabric is 100G today and 400G is a dated cutover, say so. Buying RG-S6580-48CQ8QC “just in case” while lighting only 100G ports is a commercial choice, not a technical requirement — put the cutover date on the RFQ. If there is no 400G plan, prefer RG-S6520-64CQ or CE8850-32CQ-EI.
See the full side-by-side: RG-S6520-64CQ vs RG-S6580-48CQ8QC.
Common purchasing mistakes
- Putting a 10G leaf such as S6805-54HF on a 100G spine shortlist.
- Choosing the highest Tbps number without counting ports.
- Ignoring rack depth on the 400G PID.
- Mixing campus aggregation PIDs such as S5732-H48S6Q into a fixed 100G RFQ.
- Ordering optics after the switch arrives instead of on the same quote.
RFQ checklist
Guide: 100G fixed data-center switch buying guide · Request a quote
