# Data Channel Offload: supported features

This page aims at summarizing all data channel features and their support status in the DCO modules across the supported platforms.\\
New features may be added over time, therefore keep an eye on this page if interested.

Please, also note that some features, like compression are considered to be legacy and expected to never be implemented in ovpn-dco. This is a design decision aimed at keeping ovpn-dco as simple as possible, while also taking the chance to drop those functionalities that are not consider useful anymore (or even harmful!).

## Supported features by platform

This table is constantly work in progress, therefore expect changes over time.

|**Feature**|**Windows**|**Linux**|**FreeBSD**|**Remark**|
|-|-|-|-|-|
|TUN mode (L3)| yes| yes| yes| |
|TAP mode (L2)| no| no| no| not planned|
|Mode: client, P2MP/server| client, server | client, server| client, server| |
|UDP as transport| yes| yes| yes| |
|TCP as transport| yes (not for server)| yes| no| |
|Ciphers| AES-GCM| AES-GCM| AES-GCM| |
| | ChaCha20-Poly1305 (Win11 only)| ChaCha20-Poly1305| ChaCha20-Poly1305| |
|AEAD Epoch Keys| no | no | no | desirable |
|Internal routes handling ```--iroute```| yes| standard system routes| yes (do not use identical route/iroute masks)| |
|Outside fragmentation (inside MTU 1500)| yes| handled by kernel| yes (to be tested)| |
|OpenVPN fragmentation (```--fragment```)| no| no| no| not planned|
|MSS mangling ```--mssfix```| yes| no (can be done via nft)| no (can be done via pf)| desirable|
|Compression| no| no| no| not planned|
|OCC packets in data channel| ?| no| ?| required for mtu-test (other use cases?) |
|RPF check (server only)| n/a| yes| ?|
|Topology other than subnet ```--topology net30\|p2p```| no| no| no| not planned|
|--float on TLS server|yes |yes|no|2.7_alpha3 needed to receive kernel notifications|
|--float on TLS client|no|no|no||