Use this buying guide when the switch you are purchasing is itself a fixed 100G or 400G platform. It is not a server-leaf guide for 10G/25G NICs and not a campus PoE guide.
If servers are 10G or 25G, open the data-center leaf buying guide instead.
CE8850-32CQ-EI
RG-S6520-64CQ
RG-S6580-48CQ8QCGrounded specification matrix
| Model | Faceplate | Capacity | Forwarding | PSU | Rack note |
|---|---|---|---|---|---|
| CE8850-32CQ-EI | 32 × 100GE + 2 × 10GE | 6.4 Tbps | 3,200 Mpps | Dual hot-swap | ~1U; ~442×420×43.6 mm |
| RG-S6520-64CQ | 64 × 100GE QSFP28 | 12.8 Tbps | 4482 Mpps | 1+1 | 2U class; ~442×450×88.1 mm |
| RG-S6580-48CQ8QC | 48 × 100GE + 8 × 400GE | 16.0 Tbps | 5350 Mpps | 1+1 | 1U height; confirm ~700 mm depth |
Buyer decision workflow
| If your answer is… | Then shortlist… |
|---|---|
| Servers/links need ≤32 × 100G and no 400G | CE8850-32CQ-EI |
| Every port is 100G and density must be 64 | RG-S6520-64CQ |
| 400G ports are on the optic plan now | RG-S6580-48CQ8QC |
| Servers are 10G with 100G uplinks only | Leave this guide — use S6805-54HF class / leaf guide |
| Campus GE/10G aggregation | Leave this guide — use 10G aggregation guide |
Oversubscription, capacity, forwarding
Write the north/south bandwidth target before comparing Tbps marketing lines. Forwarding Mpps matters for small-packet designs; many storage/AI fabrics are bandwidth-bound first. Do not treat a higher Tbps figure as an automatic win.
Optics, breakout, redundancy, airflow
- List optic PID families on the RFQ (SR/DR/FR/LR class as applicable) — do not order “QSFP28 generic”.
- Breakout only when peer NICs and software trains are named.
- Require 1+1 or dual PSU language on the quote response.
- State airflow direction for the row.
Common mistakes
- RFQ mixes campus PoE PIDs with fixed 100G spines.
- Buying 400G ports with no 400G optic budget.
- Ignoring 2U height on RG-S6520-64CQ.
- Assuming breakout without naming the peer.
Questions before RFQ
How many 100G ports will be lit on day one?
That number usually decides 32 vs 64 before brand does.
Are any 400G optics already specified?
If yes, start from RG-S6580-48CQ8QC. If no, do not buy 400G ports for decoration.
Is this definitely not a 10G leaf?
If server NICs are 10G, use the leaf guide. S6805-54HF is the Batch-3 example of that class.
What documentation do you need with the quote?
Ask for the datasheet pages covering ports, capacity, PSU, and dimensions when your design review requires them.