Bill of Materials: build this AI fabric for real
2 spines, 3 leaves, BGP unnumbered on FRRouting. Open-networking white-box switches running SONiC, which uses FRR, so the lab config carries straight over.
← Back to the lab · Prices approx., at time of recording, Oct 2026.
1Summary
| Line item | Qty | Unit price | Extended |
|---|---|---|---|
| SONiC network OS (runs FRR) | 5 | free | $0.00 |
| Edgecore AS7726-32X spine (32x100G, AC) | 2 | $9,180.99 | $18,361.98 |
| Edgecore AS7326-56X leaf (48x25G + 8x100G, AC) | 3 | $8,345.99 | $25,037.97 |
| 100G QSFP28 DAC, 2 m (leaf to spine) | 6 | $142.99 | $857.94 |
| 25G SFP28 DAC, 2 m (leaf to server) | 3 | $51.99 | $155.97 |
| Dual-port 25G SFP28 NIC (ConnectX-6 Lx) | 3 | $317.99 | $953.97 |
| Linux servers (any Linux box you have) | 3 | BYO | not counted |
| Total (fabric + cabling + NICs) | $45,367.83 |
Prices approx., at time of recording, Oct 2026. Servers are whatever Linux boxes you already have, so they are not in the total. Before tax, shipping, and rack/power.
Watch the leaf listing: one popular AS7326-56X listing (AVENDOR, $7,228.99) is the −48V DC power version for telco racks. For a normal rack with AC power, choose the AC model (dual AC PSUs) linked below.
2Components
SONiC (Software for Open Networking in the Cloud)
- Open-source Linux network OS, open-sourced by Microsoft in 2016, now under the Linux Foundation
- Uses FRRouting for BGP, the same routing suite as the lab
- Installs onto white-box switches through ONIE
Role in the topology: Runs on every spine and leaf. Your router bgp / BGP-unnumbered config from the lab carries over almost line for line.
Edgecore AS7726-32X (DCS204)
- 32 × 100G QSFP28 ports
- Broadcom Trident 3
- ONIE installer, so you can load SONiC
- Dual AC power, front-to-back airflow (7726-32X-O-AC-F-US)
Role in the topology: spine1 and spine2. Every leaf has one 100G uplink to each spine, so ECMP has two equal paths.
Edgecore AS7326-56X (DCS203)
- 48 × 25G SFP28 down to servers
- 8 × 100G QSFP28 up to spines
- ONIE, SONiC-ready
- Dual AC PSUs, front-to-back airflow
Role in the topology: leaf1, leaf2, leaf3. Two 100G uplinks each (one per spine), 25G down to the GPU/compute host.
100G QSFP28 passive DAC, 2 m (MCP1600-C002E30N)
- 100GbE (100GBASE-CR4) passive copper, QSFP28 both ends
- No optics, no power draw, lowest latency
- 2 m reaches across adjacent racks; 1 m version is $125.99
Role in the topology: The 6 fabric links: 3 leaves × 2 spines. These are the point-to-point links BGP unnumbered peers over with IPv6 link-local addresses.
25G SFP28 passive DAC, 2 m (Dell 470-ACFB)
- 25GbE SFP28 to SFP28 direct-attach copper
- New, sealed
- Standard MSA cable; any SFP28 DAC of this length works
Role in the topology: One per server: leaf SFP28 port to the server NIC.
Linux server + dual-port 25G SFP28 NIC (ConnectX-6 Lx MCX631102AN-ADAT)
- Servers: any Linux box with a free PCIe slot
- NIC: 2 × 25G SFP28, PCIe 4.0 x8
- RoCE-capable, standard in-box Linux driver (mlx5)
Role in the topology: host1, host2, host3, one per leaf. Second port is there if you later dual-home hosts to two leaves.
The free version: GNS3 + FRR containers
Exactly what we built in the lesson: the same 2-spine / 3-leaf topology, the same FRR BGP-unnumbered config, ECMP and BFD, all on one machine.
← Build it free in the lab