Users Guide

Table Of Contents
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
VLANs Link MTU cannot be higher than 1518 bytes and its IP MTU cannot be higher than 1500 bytes.
Packet handling during MTU mismatch
When you configure the MTU size on an interface, ensure that the MTU size of both ingress and egress
interfaces are set to the same value for IPv4 traffic to work correctly. If there is an MTU mismatch
between the ingress and egress interface, there may be a high CPU usage. If egress interface MTU size is
smaller than the ingress interface, packets may get fragmented.
The following describes the difference between Link MTU and IP MTU.
Layer 2
Overhead
Difference between Link MTU and IP MTU
Ethernet
(untagged)
18 bytes
VLAN Tag Tag 22 bytes
Untagged Packet
with VLAN-Stack
Header
22 bytes
Tagged Packet
with VLAN-Stack
Header
26 bytes
Related
Commands
mtu set the link MTU for an Ethernet interface.
ip name-server
Enter up to six IPv4 addresses of name servers. The order you enter the addresses determines the order of their use.
Syntax
ip name-server ipv4-address [ipv4-address2...ipv4-address6]
To remove a name server, use the no ip name-server ip-address command.
Parameters
ipv4-address
Enter the IPv4 address, in dotted decimal format, of the name server to be used.
ipv4-address2...
ipv4-address6
(OPTIONAL) Enter up five more IPv4 addresses, in dotted decimal format, of name
servers to be used. Separate the addresses with a space.
Defaults No name servers are configured.
Command Modes CONFIGURATION
Command
History
This guide is platform-specific. For command information about other platforms, see the relevant Dell
EMC Networking OS Command Line Reference Guide.
Version Description
9.10(0.1) Introduced on the S6010-ON and S4048T-ON.
9.10(0.0) Introduced on the S3148.
9.10(0.0) Introduced on the S6100ON.
9.8(2.0) Introduced on the S3100 series.
9.8(1.0) Introduced on the Z9100ON.
9.8(0.0P5) Introduced on the S4048-ON.
IPv4 Routing 791