Dell Force10 MXL Blade MXL 10/40GbE Switch IO Module FTOS Command Line Referen - Page 253

Parameters value Enter a maximum frame size in bytes. Range: 594 to 9252 MXL Switch Range: 594 to 12000 Default: 1554 Defaults 1554 Command Modes INTERFACE Command History Version 8.3.16.1 Introduced on MXL 10/40GbE Switch IO Module Usage Information If the packet includes a Layer 2 header, the difference between the link MTU and IP MTU (ip mtu command) must be enough bytes to include the Layer 2 header: • The IP MTU will get adjusted automatically when the Layer 2 MTU is configured with the mtu command. When you enter the no mtu command, FTOS reduces the IP MTU value to 1536 bytes. Link MTU and IP MTU considerations for port channels and VLANs are as follows. port channels: • All members must have the same link MTU value and the same IP MTU value. • The port channel link MTU and IP MTU must be less than or equal to the link MTU and IP MTU values configured on the channel members. Example: if the members have a link MTU of 2100 and an IP MTU 2000, the port channel's MTU values cannot be higher than 2100 for link MTU or 2000 bytes for IP MTU. VLANs: • All members of a VLAN must have same IP MTU value. • Members can have different Link MTU values. Tagged members must have a link MTU 4 bytes higher than untagged members to account for the packet tag. • The VLAN link MTU and IP MTU must be less than or equal to the link MTU and IP MTU values configured on the VLAN members. Example The VLAN contains tagged members with Link MTU of 1522 and IP MTU of 1500 and untagged members with Link MTU of 1518 and IP MTU of 1500. The VLAN's Link MTU cannot be higher than 1518 bytes and its IP MTU cannot be higher than 1500 bytes. Table 14-3. Difference between Link MTU and IP MTU Layer 2 Overhead Ethernet (untagged) VLAN Tag Untagged Packet with VLAN-Stack Header Tagged Packet with VLAN-Stack Header Link MTU and IP MTU Delta 18 bytes 22 bytes 22 bytes 26 bytes Interfaces | 253