Port Speed Overview

Learn about port speed on a device or line card, support for multiple port speed details, guidelines and how to configure the port speed.

Introduction to Port Speed

Port speed refers to the maximum amount of data that the line card transmits through a port at any given second. Port speed is measured as follows:

Kilobits per second (Kbps)
Gigabits per second (Gbps)
Terabits per second (Tbps)

Table 1 describes the different types of port speed configuration.

Table 2 describes the naming formats for the channelized and non-channelized interfaces.

Table 3 lists the line cards and devices, the port profile configuration, and link to the same.

Configure Port Speed - PIC Level describes the port speed configuration at PIC Level - Chassis Hierarchy.

Configure Port Speed - Port Level describes the port speed configuration at Port Level - Chassis Hierarchy.

Configure Port Speed for Non-Channelized Interfaces describes the steps to configure the port speed for non-channelized interfaces from the [edit interfaces] hierarchy.

Configure Port Speed for Channelized Interfaces describes the steps to configure the port speed for channelized interfaces from the [edit interfaces] hierarchy.

Table 1: Types of Port Speed Configuration
Port Speed Configuration Type	Description
PIC or MIC Level	You can configure all the ports in one PIC or MIC to operate at the same speed. For example, you can configure all the ports of a PIC that support port speed of 100 Gbps to operate at 100 Gbps speed. If you do not specify the speed by using the `pic-mode` statement, then the port operates in the default speed.
Port Level	You can configure each port to operate at a different speed and thus enable each port. When you configure the port speed at the port level, you have the flexibility of operating the ports of the line card at different supported speeds. When you change the speed of a specific port in a given PIC using the `speed` statement, then only the speed of that port is modified. All other ports in the PIC remain unaffected. For example, you can configure four 10-Gigabit Ethernet interfaces on port 0, one 40-Gigabit Ethernet interface on port 1, and one 100-Gigabit Ethernet interface on port 2.

Interface Naming Conventions
What is Oversubscription?
Supported Line Cards and Devices

Interface Naming Conventions

Each interface name includes a unique identifier and follows a naming convention. When you configure the interface, use the interface name. You can either configure a port as a single interface (non channelized interface) or partition the port into smaller data channels or multiple interfaces (channelized interfaces).

When multiple interfaces are supported on a physical port, you use the colon (:) notation in the interface naming conventions as a delimiter to differentiate the multiple interfaces on a physical port. In the interface naming convention, xe-x/y/z:channel:

x refers to the FPC slot number.
y refers to the PIC slot number.
z refers to the physical port number.
channel refers to the number of channelized interfaces.

When the 40-Gigabit Ethernet interfaces (et-fpc/pic/port) are channelized as 10-Gigabit Ethernet interfaces, the interface appears in the xe-fpc/pic/port:channel format, and channel is a value of 0 through 3.

Table 2: Channelized and Non-Channelized Interface Naming Formats
Interfaces	Non-channelized Interfaces Naming Formats	Channelized Interfaces Naming Formats
10-Gigabit Ethernet Interfaces	Prefix is `xe-`. The interface name appears in the `xe-fpc/pic/port` format.	Prefix is `xe-`. The interface name appears in the `xe-fpc/pic/port:channel` format.
25-Gigabit Ethernet Interfaces, 40-Gigabit Ethernet Interfaces, 100-Gigabit Ethernet Interfaces, 200-Gigabit Ethernet Interfaces, and 400-Gigabit Ethernet Interfaces.	Prefix is `et-`. The interface name appears in the `et-fpc/pic/port` format.	Prefix is `et-`. The interface name appears in the `et-fpc/pic/port:channel` format.

What is Oversubscription?

Oversubscription occurs when you configure the speed of a port at the PIC level, and all ports that support that speed are enabled. To prevent oversubscription, you can configure the number of active ports that operate at the configured speed. Interfaces are created only for active ports. When oversubscription of Packet Forwarding Capacity is not supported, the demand on each Packet Forwarding Engine should be less than or equal to its forwarding capacity.

Supported Line Cards and Devices