Network Engineering
MTU Path Discovery Reference
Search MTU and PMTUD concepts — Ethernet MTU, VXLAN overhead, PMTUD black holes, MSS clamping, and jumbo frame requirements across network paths.
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About this tool
MTU Path Discovery Reference
The MTU Path Discovery Reference covers Ethernet MTU, VXLAN/overlay overhead, PMTUD black hole detection, MSS clamping, and jumbo frame end-to-end requirements.
• Look up VXLAN MTU overhead before configuring a physical underlay network
• Understand PMTUD black hole symptoms before debugging a TCP stall
• Find MSS clamping configuration for a PMTUD-blocking environment
• Check jumbo frame path requirements before enabling 9000 byte MTU
Next step
Bandwidth-Delay Product Calculator — Calculate TCP bandwidth-delay product and required buffer sizes for high-throughput links.
Open Bandwidth-Delay Product Calculator →
FAQ
What does this tool tell you?
The MTU Path Discovery Reference covers Ethernet MTU, VXLAN/overlay overhead, PMTUD black hole detection, MSS clamping, and jumbo frame end-to-end requirements.
What affects the result most?
MTU = Maximum Transmission Unit: Ethernet default 1500 bytes, jumbo frames 9000 bytes. Path MTU Discovery: sends DF-bit set packets, reduces size on ICMP Type 3 Code 4 response. PMTUD black hole: firewalls block ICMP — TCP sessions stall, never completes handshake effectively.
How should I use the result?
Use this tool to orient quickly to the concepts, field names, or values you are about to look up in a full specification or vendor documentation. It summarizes the common cases; the authoritative source remains whichever standard or vendor doc defines the values themselves.
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