MTU is the largest PDU that can be passed or transmitted, in bytes, by an interface on a specific protocol.
- Default Layer 3 IPv4 MTU is 1500.
- Jumbo Ethernet MTU up to 9216
- WLAN MTU 7981
- FDDI MTU 4352
Some caveats here for CCNP Studies so far:
- Don’t mess with MTU unless you know what you’re doing. Most MTU’s are left at 1504 or 1514 unless it’s a 10gig link.
- Not required to match for EIGRP neighborship
- Just to make sure, use #ping command with large packet sizes or df-bit set over a link to test MTU