# Ethernet: jumbo frame size 9600 bytes exceeds interface MTU 1500 on eth0, packet dropped

- **ID:** `networking/ethernet-jumbo-frame-mtu-exceeded`
- **Domain:** networking
- **Category:** network_error
- **Verification:** ai_generated
- **Fix Rate:** 76%

## Root Cause

A device attempted to send a jumbo frame larger than the interface MTU, causing the packet to be dropped at the data link layer without fragmentation.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| Linux kernel 6.1.0 | active | — | — |
| Cisco IOS 15.2(7)E | active | — | — |
| Mellanox ConnectX-5 firmware 16.32.1016 | active | — | — |

## Workarounds

1. **Increase the interface MTU to accommodate jumbo frames: `ip link set dev eth0 mtu 9000` on Linux, or `mtu 9000` in interface config on Cisco switches.** (95% success)
   ```
   Increase the interface MTU to accommodate jumbo frames: `ip link set dev eth0 mtu 9000` on Linux, or `mtu 9000` in interface config on Cisco switches.
   ```
2. **Ensure all devices in the path support jumbo frames by checking with `ping -M do -s 8972 <destination>` (Linux) to test large packet delivery.** (85% success)
   ```
   Ensure all devices in the path support jumbo frames by checking with `ping -M do -s 8972 <destination>` (Linux) to test large packet delivery.
   ```
3. **Segment the network so jumbo frames are only used in dedicated storage or backup VLANs with consistent MTU settings.** (80% success)
   ```
   Segment the network so jumbo frames are only used in dedicated storage or backup VLANs with consistent MTU settings.
   ```

## Dead Ends

- **** — Jumbo frames are Layer 2 constructs; IP fragmentation applies to Layer 3 and cannot split an Ethernet frame. (95% fail)
- **** — Application buffers do not control frame size; the NIC driver segments data into MTU-sized frames. (70% fail)
- **** — An MTU of 0 is invalid and causes the interface to fail to transmit any packets. (90% fail)