Not Enough Bandwidth Legacy(NEBL)
Not Enough Bandwidth Legacy, or NEBL, is an Optimization mod that reduces the network traffic a Minecraft server sends to its players.
What it does
NEBL uses several methods to cut the data exchanged between server and client during play. Its authors compared raw uncompressed data with the compressed output and estimated a reduction to 7.6 percent of the original size, while measured values came to about 13.8 percent. In a vanilla test environment the server's outbound traffic fell to 18 percent of the original size. The mod is a backport of Enough Bandwidth, ported to older Minecraft versions with the original author's permission, and it works the same way as the original NEB.
NEBL targets common vanilla patterns. It batches many small network packets into one larger packet, held for up to 20 milliseconds before sending, and it delays forgetting chunks a player has left so that returning to them does not require resending the full chunk data. Packet headers are replaced with compact identifiers, which keeps overhead fixed at 3 to 4 bytes. The mod is open source under the GNU General Public License v3.0 or later, and it is published for Forge and NeoForge across the 1.12.2 – 1.21.1 range.
Key features
Compact packet headers
Packet identifiers are replaced with an index, so each mod's packet header takes a fixed 3 to 4 bytes instead of a long string.
Packet batching
Many small packets sent by vanilla are combined into one larger packet and sent after a 20 millisecond window.
Delayed chunk forgetting
Chunks the player leaves behind are kept for a while, so returning to them does not require resending full chunk data.
Compatibility blacklist
A compatibility mode with a blacklist lets server owners list packets that NEBL should skip, with a default list that includes Velocity-related packets.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
How it compares
BandwidthOptimizer is open source under the GNU Lesser General Public License v2.1 or later, built for Fabric, Forge, NeoForge and Quilt 1.19.2 – 26.2, and needs both client and server. ZstdMC is open source under the MIT License, only for NeoForge 1.21.1, and also needs both sides. ZSTD Compresser is open source under the GNU Affero General Public License v3.0 only, covers 1.20.1 – 1.21.1 on Fabric, Forge and NeoForge, and is client-side only.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Not Enough Bandwidth Legacy(NEBL) | Forge and NeoForge | 1.12.2 – 1.21.1 | Client and server | 2026-08-19 |
| BandwidthOptimizer | Fabric, Forge, NeoForge and Quilt | 1.19.2 – 26.2 | Client and server | 2026-10-12 |
| ZstdMC | NeoForge | 1.21.1 | Client and server | 2026-02-20 |
| ZSTD Compresser | Fabric, Forge and NeoForge | 1.20.1 – 1.21.1 | Client-side only | 2026-05-30 |
Questions
Does NEBL need to be installed on the server?
Which loaders does NEBL support?
What is the compatibility blacklist for?
In the catalog
Not Enough Bandwidth Legacy(NEBL) is one of 3,545 Optimization mods on ModsFinder, and one of 1,441 Optimization mods for Forge. 32,366 mods support Minecraft 1.21.1.
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What the author says
This is a backport of Not Enough Bandwidth. With the original author's permission, we have ported it to an older version of Minecraft, and its functionality is basically the same as the original NEB. NEBL uses various methods to save as much network traffic as possible during Minecraft gameplay, while remaining…
Official listing
- Modrinth page
- modrinth.com/mod/not-enough-bandwidth-legacy-nebl
- Owner
- MapleSugar365
- Published
- 2026-04-23
- Updated on Modrinth
- 2026-08-19
- Facts verified
- 2026-10-15