By default, both of the built-in Fast Ethernet ports on the M7i router FIC autonegotiate whether to operate at 10 Mbps or 100 Mbps. All other interfaces automatically choose the correct speed based on the PIC type and whether the PIC is configured to operate in multiplexed mode (using the no-concatenate statement at the [edit chassis] hierarchy level, as described in the JUNOS System Basics Configuration Guide).
If the link partner does not support autonegotiation, configure either Fast Ethernet port manually to match its link partner's speed and link mode. When the link mode is configured, autonegotiation is disabled.
To configure a Fast Ethernet port on the FIC to operate at 10 Mbps or 100 Mbps, include the speed statement at the [edit interfaces fe-fpc/pic/port] hierarchy level:
- [edit interfaces fe-fpc/pic/port]
-
speed (10m | 100m);
For information about configuring the link mode, see Configuring the Link Characteristics.