AudioCodes Mediant 1000B User Manual page 141

User's Manual
Parameter
MTU
mtu
[DeviceTable_MTU]
Version 7.2
on this Ethernet Group are discarded.
Note: Only one Ethernet Device can be configured as Untagged
per associated Ethernet Group. In other words, if multiple
Ethernet Devices are associated with the same Ethernet Group,
only one of these Ethernet Devices can be configured to
Untagged; all the others must be configured to Tagged.
Defines the Maximum Transmission Unit (MTU) in bytes per
VLAN (Ethernet Device).
The valid value is 68 to1,500. The default is 1,500.
Note:

MTU is not applicable to SBC Direct Media traffic and to
debug recording traffic.

If your first Ethernet Device is configured with an untagged
VLAN, its MTU value is the maximum MTU that can be
configured for all other Ethernet Devices that are associated
with the same Ethernet Group. In other words, if you
configure additional Ethernet Devices (tagged VLANs) that
are associated with the same Ethernet Group, their MTUs
must be equal to or less than the MTU of the first Ethernet
Device (untagged VLAN). For example, if the untagged VLAN
is configured with MTU of 100 bytes, you can configure a
tagged VLAN with an MTU value of either 100 bytes or less.

If your first Ethernet Device is configured with a tagged VLAN
and you later configure an additional Ethernet Device with an
untagged VLAN that is associated with the same Ethernet
Group, the MTU of the untagged VLAN must be equal to or
greater than the highest MTU value configured out of all the
Ethernet Devices (VLANs) associated with the Ethernet
Group. For example, if VLAN 1 is configured with the highest
MTU (100 bytes) out of all your VLANs, you can configure an
untagged VLAN with an MTU value of either 100 bytes or
greater.
141
Description
Mediant 1000B Gateway & E-SBC
12. Network