Configuring the Interface Speed

You can configure the interface speed on the following interfaces:

• Management Ethernet Interface on M-series and T-series Routing Platforms
• Gigabit Ethernet Interfaces on J-series Services Routers
• Fast Ethernet Interface
• Tri-Rate Ethernet Copper Interface
• SONET/SDH Interface

Management Ethernet Interface on M-series and T-series Routing Platforms

By default, the M-series and T-series routing platforms management Ethernet interface, fxp0, autonegotiates whether to operate at 10 megabits per second (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 in the [edit chassis] configuration hierarchy, as described in the JUNOS System Basics Configuration Guide).

To configure the management Ethernet interface to operate at 10 Mbps or 100 Mbps, include the speed statement at the [edit interfaces fxp0] hierarchy level:

For information about configuring the link mode, see Configuring the Link Characteristics on Ethernet Interfaces.

Note: The fxp0 interface does not support CoS.

Gigabit Ethernet Interfaces on J-series Services Routers

By default, Gigabit Ethernet interfaces (both built-in and PIMs) for J-series Services Routers autonegotiate whether to operate at 10 megabits per second (Mbps), 100 Mbps, or 1000 Mbps.

To configure a J-series Gigabit Ethernet interface to operate at 10 Mbps, 100 Mbps, or 1000 Mbps, include the speed statement at the [edit interfaces ge-pim/0/port] hierarchy level:

For information about configuring the link mode, see Configuring the Link Characteristics on Ethernet Interfaces.

Fast Ethernet Interface

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.

Note: When you manually configure Fast Ethernet interfaces on the M-series and T-series routers, link mode and speed must both be configured. If both these values are not configured, the router uses autonegotiation for the link and ignores the user-configured settings.

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:

For information about configuring the link mode, see Configuring the Link Characteristics on Ethernet Interfaces.

Tri-Rate Ethernet Copper Interface

By default, the Tri-Rate Ethernet copper interfaces on MX-series routers operate at 1 Gbps. Tri-Rate Ethernet copper interfaces can also be configured to operate at 10 Mbps, 100 Mbps, or 1 Gbps.

Note: When you configure the Tri-Rate Ethernet copper interface to operate at 1 Gbps, autonegotiation must be enabled.

Note: Half-duplex mode is not supported on Tri-Rate Ethernet copper interfaces.

To configure a Tri-Rate Ethernet copper interface to operate at 10 Mbps, 100 Mbps, or 1 Gbps, include the speed statement at the [edit interfaces ge-fpc/pic/port] hierarchy level:

For information about configuring the link mode, see Configuring the Link Characteristics on Ethernet Interfaces.

SONET/SDH Interface

You can configure the speed of SONET/SDH interfaces on next-generation SONET/SDH Type 1 and Type 2 PICs with SFP. The speed you select is dependent upon whether the PIC is in concatenated or nonconcatenated mode. In concatenated mode, the bandwidth of the interface is in a single channel. In nonconcatenated mode, the PIC operates in channelized (multiplexed) mode.

Table 21 shows the mode combinations for the next-generation SONET/SDH Type 1 PICs with SFP.

Table 21: Type 1 PIC Mode Combinations

Table 22 shows the mode combinations for the next-generation SONET/SDH Type 2 PICs with SFP.

Table 22: Type 2 PIC Mode Combinations

By default, SONET/SDH PICs operate in concatenated mode. To specify interface speed in concatenated mode, include the speed statement with options at the [edit interfaces so-fpc/pic/port] hierarchy level:

For example, each port of the 4-port OC12 PIC can be configured to be in OC3 or OC12 speed independently when this PIC is in 4xOC12 concatenated mode.

To specify interface speed in nonconcatenated mode, include the speed statement at the [edit interfaces so-fpc/pic/port.channel] hierarchy level:

To configure the PIC to operate in channelized (multiplexed) mode, include the no-concatenate statement at the [edit chassis fpc slot-number pic pic-number] hierarchy level.

For more information about using the no-concatenate statement, see the JUNOS System Basics Configuration Guide.

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