Dell C9000 Series Reference Manual page 951

The following is a list of the Dell Networking OS version history for this command.
Version
9.9(0.0)
9.2(1.0)
8.3.19.0
8.3.11.1
8.3.7.0
8.1.1.0
7.5.1.0
6.2.1.0
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.
When you enter the no mtu command, the system reduces the IP MTU value to 1536
bytes.
Link MTU and IP MTU considerations for port channels and VLANs are as follows.
port channels:
•
•
VLANs:
•
•
•
The following shows the difference between Link MTU and IP MTU.
Layer 2
Overhead
Ethernet
(untagged)
VLAN Tag
Description
Introduced on the C9010.
Introduced on the Z9500.
Introduced on the S4820T.
Introduced on the Z9000.
Introduced on the S4810.
Introduced on the E-Series ExaScale.
Introduced on the C-Series.
Introduced on the E-Series.
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. For 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.
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. For 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.
Link MTU and IP MTU Delta
18 bytes
22 bytes
Interfaces 951