Jumbo Frame Support for ThousandEyes Network Tests

Overview

We are extending ThousandEyes Enterprise Agent network testing with configurable jumbo frame probes. Jumbo frames carry more data than standard Ethernet frames, which typically support a maximum transmission unit (MTU) of 1,500 bytes. They help modern data centers move large volumes of traffic efficiently, including between servers within the data center.

Tests with small packets can succeed even when problems affect larger ones. This enhancement lets teams test larger packet sizes used by applications and uncover Path MTU mismatches, packet fragmentation, and silent packet loss. This helps validate that a network configured for jumbo frames can support the workloads that depend on it.

Feature Highlights

• Larger Test Packets: Configure Agent-to-Server Ping Payload Size and Agent-to-Agent UDP Payload Size or TCP maximum segment size (MSS) up to a packet size of 9,216 bytes. These settings expand testing beyond the previous 1,400-byte payload limit.

• Flexible Size Configuration: Use Auto to derive a value from the agent’s interface configuration, or Manual to choose a specific payload or MSS. Agent interfaces must support the resulting packet size, including protocol headers; Auto does not guarantee the maximum size.

• Path MTU Visibility: Use existing MTU discovery to find the largest packet size that can cross a path without fragmentation, up to 9,216 bytes. Path Visualization shows the minimum Path MTU and highlights which hops lower the Path MTU.

• Fixed Probes and MTU Discovery: Combine a manual size with MTU discovery to perform separate fixed-size and discovery measurements. Larger fixed probes can expose packet loss even when blocked network feedback messages (ICMP) prevent reliable Path MTU discovery.

Customer Benefits 

• Earlier Issue Detection: Identify problems that affect large packets before they disrupt storage transfers or other applications that rely on jumbo frames. 

• More Representative Monitoring: Validate network behavior using packet sizes that better reflect application traffic across high-throughput paths. 

• Greater Confidence in Changes: Compare test results before and after software upgrades, hardware refreshes, or configuration changes to confirm that jumbo frame networks continue to work as expected. 

With jumbo probes, ThousandEyes helps teams validate the packet sizes their applications depend on and investigate issues that standard-size tests can overlook.