Nokia 7705 SAR - Page 372

7705 SAR Interfaces
372
Interface Configuration Guide
3HE 11011 AAAC TQZZA Edition: 01
mtu
Syntax mtu mtu-bytes
no mtu
Context config>port>ethernet
config>port>dsl
config>port>gpon
Description This command configures the maximum payload MTU size for an Ethernet port, v-port on
Ethernet Ring adapter card, DSL, or GPON port (for ring Ethernet ports, the MTU value is
fixed at 9728 bytes).
The port-level MTU parameter indirectly defines the largest physical packet the port can
transmit or the far-end Ethernet port can receive. Packets to be transmitted over a given port
that are larger than the MTU of the port will be fragmented or discarded, depending on
whether the DF bit is set in the packet header.
If the port mode or encapsulation type is changed, the MTU assumes the default values of
the new mode or encapsulation type.
The no form of this command restores the default values.
Default The default MTU value depends on the port type, mode, and encapsulation as listed in
Table 25.
Parameters mtu-bytes — sets the maximum allowable size of the MTU, expressed as an integer (see
Table 25)
Values 128 to 9732 bytes (Ethernet ports)
512 to 9732 bytes (DSL ports on 7705 SAR-Wx)
512 to 2106 bytes (DSL and GPON ports on 7705 SAR-M)
Table 25 Port MTU Default and Maximum Values
Port Type Mode Encap Type Default (bytes) Max MTU (bytes)
10/100 Ethernet
1
Access/
Network
null 1514
9724
2
dot1q 1518
9728
2
qinq
3
1522 (access only)
9732 (access only)
2
GigE SFP
1
and
10-GigE SFP+
Access/
Network
null 1514 (access)
1572 (network)
9724 (access and
network)
dot1q 1518 (access)
1572 (network)
9728 (access and
network)
qinq
3
1522 (access only) 9732 (access only)