Mtu Configuration Guidelines; Table 24: Mtu Default Values - Alcatel-Lucent 7750 SR OS Interface Configuration Manual

MTU Configuration Guidelines

Observe the following general rules when planning your service and physical MTU
configurations:
•
•
•
•
Default MTU Values
Table 24
and encapsulation.

Table 24: MTU Default Values

Ethernet
Ethernet
Fast Ethernet
Other Ethernet
SONET path or TDM channel
SONET path or TDM channel
SONET path or TDM channel
SONET path or TDM channel
SONET path or TDM channel
SONET path or TDM channel
*The default MTU for Ethernet ports other than Fast Ethernet is actually the lesser of 9212 and
any MTU limitations imposed by hardware which is typically 16K.
7750 SR OS Interface Configuration Guide
The 7750 SR must contend with MTU limitations at many service points. The physical
(access and network) port, service, and SDP MTU values must be individually defined.
Identify the ports that will be designated as network ports intended to carry service traffic.
MTU values should not be modified frequently.
MTU values must conform to both of the following conditions:
→ The service MTU must be less than or equal to the SDP path MTU.
→ The service MTU must be less than or equal to the access port (SAP) MTU.
displays the default MTU values which are dependent upon the (sub-) port type, mode,
Port Type
Interface Configuration
Mode Encap Type
access null
access dot1q
network —
network —
access BCP-null
access BCP-Dot1q
access IPCP
network —
access frame-relay
access atm
Default
(bytes)
1514
1518
1514
9212*
1518
1522
1502
9208
1578
1524
Page 135