Dent

---
name: dent
description: "Expert coverage of DENT (DentOS) open-source NOS for enterprise edge and retail networking: Linux switchdev model, PoE management, FRRouting, standard Linux networking tools, Amazon Just Walk Out deployments, and enterprise branch/retail use cases. Use for \"DENT\", \"DentOS\", \"switchdev\", \"enterprise edge NOS\", \"open source switch\", \"Just Walk Out\", \"Linux NOS edge\". Do NOT use for cross-vendor comparison, platform selection, or category-wide architecture -- use the `dc-fabric` skill."
license: MIT
---

# DENT (DentOS)

This skill covers DENT (DentOS), the Linux Foundation open-source NOS for distributed enterprise edge and retail networking. Current version: DentOS 3.0 "Cynthia". Areas of expertise include:

- Linux switchdev driver model: Kernel-native hardware offload, ip/bridge/tc tooling
- PoE/PoE+ management: Power over Ethernet for cameras, APs, VoIP phones, sensors
- FRRouting (FRR): BGP, OSPF for branch uplinks and WAN connectivity
- Standard Linux networking: iproute2, bridge, tc, netfilter, iptables
- NETCONF/RESTCONF and YANG models for programmatic management (DentOS 3.0)
- Amazon Just Walk Out Technology infrastructure
- Enterprise edge, retail, and branch use cases

## How to Approach Tasks

1. **Classify** the request:
   - **Architecture** -- switchdev model, Linux kernel networking, hardware offload
   - **Configuration** -- Standard Linux networking commands (ip, bridge, tc)
   - **PoE management** -- Power budget, port priority, device power classification
   - **Routing** -- FRR configuration for branch uplinks (BGP, OSPF)
   - **Automation** -- NETCONF/YANG, Ansible, standard Linux automation
   - **Use case design** -- Retail, warehouse, branch, campus edge deployment

2. **Understand the switchdev difference** -- DENT uses the Linux kernel switchdev driver model, not SAI. This means Linux's own routing table is the source of truth, and standard Linux tools work directly. Hardware acceleration is transparent.

3. **Analyze** -- Apply DENT-specific reasoning. DENT is purpose-built for enterprise edge, not data center. Consider PoE budget, port density, simplified management, and cost sensitivity.

4. **Recommend** -- Provide actionable guidance using standard Linux commands and FRR configuration.

## switchdev vs SAI

DENT's fundamental architectural difference from SONiC is the use of Linux kernel switchdev:

| Aspect | DENT (switchdev) | SONiC (SAI) |
|---|---|---|
| **Abstraction** | Linux kernel switchdev driver | SAI vendor library |
| **Route programming** | Linux routing stack -> kernel -> ASIC offload | SwSS -> syncd -> vendor SAI |
| **OS integration** | Native Linux tooling works directly | Requires SONiC-specific CLI/API |
| **Management** | ip, bridge, tc, iproute2, iptables | SONiC CLI, ConfigDB, YANG |
| **ASIC support** | Kernel driver per ASIC family | Vendor-provided SAI per ASIC |
| **Transparency** | Full Linux stack visibility | Abstracted behind SAI |

switchdev means the Linux kernel's routing table is the source of truth. Forwarding entries are "offloaded" to the ASIC automatically when the switchdev driver supports the operation. If a feature cannot be offloaded, it falls back to software forwarding in the kernel.

## Core Capabilities

### L2 Switching

```bash
# Create a VLAN-aware bridge
ip link add name br0 type bridge vlan_filtering 1
ip link set br0 up

# Add ports to bridge
ip link set swp1 master br0
ip link set swp2 master br0

# Configure VLANs
bridge vlan add vid 100 dev swp1
bridge vlan add vid 100 dev swp2 pvid untagged

# Show bridge MAC table
bridge fdb show

# STP/RSTP
# Managed via standard Linux bridge STP support
```

### L3 Routing

```bash
# Configure IP on interface
ip addr add 192.168.1.1/24 dev swp1

# Static route
ip route add 10.0.0.0/8 via 192.168.1.254

# Show routing table (these routes are offloaded to ASIC via switchdev)
ip route show

# Verify hardware offload
ip route show | grep offload   # "offload" flag indicates ASIC programming
```

### PoE Management

PoE/PoE+ is critical for DENT's target deployments:

- **Port power control** -- Enable/disable PoE per port
- **Power budget** -- Monitor total switch power budget and per-port consumption
- **Priority** -- Set port priority for power allocation when budget is constrained
- **Device classification** -- IEEE 802.3af (15.4W), 802.3at (30W), 802.3bt (60/90W)
- **Use cases**: IP cameras, wireless APs, VoIP phones, IoT sensors, entry/exit gates

### NAT

```bash
# NAT via Linux netfilter (offloaded to ASIC where supported)
iptables -t nat -A POSTROUTING -o swp48 -j MASQUERADE
```

### FRRouting

Same FRR stack as SONiC, Cumulus Linux, and OPNsense:

```
# FRR configuration for branch BGP uplink
router bgp 65500
  bgp router-id 10.0.0.1
  neighbor 10.0.0.2 remote-as 65000
  address-family ipv4 unicast
    network 192.168.0.0/16
```

### Network Management (DentOS 3.0)

- **YANG models** -- Data models for programmatic configuration
- **NETCONF/RESTCONF** -- Model-driven management interfaces
- **Rapid release cycle** -- Faster security patches and feature updates

## Target Use Cases

DENT targets environments where SONiC is over-engineered and proprietary NOS is over-priced:

| Use Case | Requirements | Why DENT |
|---|---|---|
| **Retail stores** | High port density, PoE, simplified management | Cost-effective, open source, PoE-native |
| **Warehouses** | Sensor/device connectivity, automation | Linux tooling, API-driven |
| **Branch offices** | WAN uplink routing, local switching | FRR routing, standard Linux |
| **Campus edge** | Access switching, PoE for APs/phones | Replace proprietary with open hardware |

### Amazon Just Walk Out

Amazon uses DentOS for cashierless retail (Just Walk Out Technology):

- Connects thousands of edge devices: cameras, weight sensors, entry/exit gates, access points
- Deployed across Amazon Go stores and partner retail locations
- Demonstrates production readiness for high-density PoE branch networking
- Amazon is a DENT founding member and primary industrial driver

## Common Pitfalls

1. **Assuming DENT is for data centers** -- DENT targets enterprise edge, not DC fabric. For data center leaf/spine, use SONiC instead.

2. **Expecting vendor CLI** -- DENT uses standard Linux tools (ip, bridge, tc), not Cisco-like CLI. Teams must be comfortable with Linux networking.

3. **Ignoring PoE budget** -- PoE switches have finite power budgets. Plan total power consumption before deploying high-power devices (802.3bt cameras, multi-radio APs).

4. **Not verifying hardware offload** -- Check `ip route show` for the "offload" flag. Routes without this flag are forwarded in software (slower, higher CPU).

5. **Treating switchdev as SAI** -- switchdev and SAI are fundamentally different abstractions. Do not apply SONiC troubleshooting patterns to DENT; use standard Linux tools instead.