This section describes the different types of interfaces supported by the device. The rest of the chapter describes configuration procedures for physical interface characteristics.

Devices within a single VLAN can communicate directly through any switch. Ports in different VLANs cannot exchange data without going through a routing device. With a standard Layer 2 device, ports in different VLANs have to exchange information through a router. By using the device with routing enabled, when you configure both VLAN 20 and VLAN 30 with an SVI to which an IP address is assigned, packets can be sent from Host A to Host B directly through the device with no need for an external router.

When the Network Advantage license is used on the device or the active device, the device uses the routing method to forward traffic between interfaces. If the Network Essentials license is used on the device or the active device, only basic routing (static routing and RIP) is supported. Whenever possible, to maintain high performance, forwarding is done by the device hardware. However, only IPv4 packets with Ethernet II encapsulation are routed in hardware.

The routing function can be enabled on all SVIs and routed ports. The device routes only IP traffic. When IP routing protocol parameters and address configuration are added to an SVI or routed port, any IP traffic received from these ports is routed.

The device supports these interface types:

• Physical ports: Device ports and routed ports

• VLANs: Switch virtual interfaces

• Port channels: EtherChannel interfaces

You can also configure a range of interfaces.

An interface on the device is represented by a 3-tuple notation that lists the module, subslot, and port.

To configure a physical interface (port), specify the interface type, module number, sub-slot number, and device port number, and enter interface configuration mode.

• Type: 25-Gigabit Ethernet (TwentyFiveGigE or twe) for 25 Gbps, 40-Gigabit Ethernet (FortyGigabitEthernet or fo) for 40 Gbps, and 100-Gigabit Ethernet (HundredGigE or hu) for 100Gbps.

• Module number: The module or slot number on the device.

• Subslot number: The subslot number is always 0.

• Port number: The interface number on the device. The port numbering starts with the far left port when facing the front of the device, for example, FortyGigabitEthernet1/0/1.

You can identify physical interfaces by physically checking the interface location on the device. You can also use the show privileged EXEC commands to display information about a specific interface or all the interfaces on the switch. The remainder of this chapter primarily provides physical interface configuration procedures.

To configure Layer 2 parameters, if the interface is in Layer 3 mode, you must enter the switchport interface configuration command without any parameters to put the interface into Layer 2 mode. This shuts down the interface and then re-enables it, which might generate messages on the device to which the interface is connected. When you put an interface that is in Layer 3 mode into Layer 2 mode, the previous configuration information related to the affected interface might be lost, and the interface is returned to its default configuration.

Note	The interface is in Layer 3 by default.

This table shows the Ethernet interface default configuration, including some features that apply only to Layer 2 interfaces.

Switch modules include SFP modules that support speeds up to 1 Gbps, SFP+ modules that support speeds up to 10 Gbps, SFP28 modules that support speeds up to 25 Gbps, QSFP modules that support speeds up to 40 Gbps and 100 Gbps.

The ethernet interfaces operate at full duplex mode. In full-duplex mode, two stations can send and receive traffic at the same time.

The Catalyst 9600 modular chassis supports up to four line cards and redundant supervisors. The supervisor has three Unified Access Data Path (UADP 3.0) ASICs connected to each other. Each UADP 3.0 ASIC provides a switching capacity of 1600Gbps full-duplex for the front panel interfaces, resulting in a total capacity of 4800 Gbps full-duplex switching capacity.

Each ASIC also provides a total of 1760 Gbps full-duplex inter-ASIC bandwidth, with 880 Gbps full-duplex to each of the other two ASICs.

The inter-ASIC connections use a broadcast network approach, to ensure that user data is available to all ASICs. In the worst-case scenario, where all traffic is inter-ASIC, the front panel bandwidth can be 2:1 oversubscribed compared to the interface-ASIC bandwidth. Most traffic scenarios (example north-to-south) will only require some traffic to be inter-ASIC.

When a Line card is installed on the chassis, one-third of its ports are connected to each ASIC. Which means, one set of ports on the line card are connected to ASIC 1, the second set to ASIC 2, and the third set of ports are connected to ASIC 3. You can view the port mapping on the line cards using the show platform software fed active ifm mapping command.

The device supports these types of Layer 3 interfaces:

• SVIs: You should configure SVIs for any VLANs for which you want to route traffic. SVIs are created when you enter a VLAN ID following the interface vlan global configuration command. To delete an SVI, use the no interface vlan global configuration command. You cannot delete interface VLAN 1.

  Note	When you create an SVI, it does not become active until it is associated with a physical port.

  When configuring SVIs, you can use the switchport autostate exclude command on a port to exclude that port from being included in determining SVI line-state. To disable autostate on the SVI, use the no autostate command on the SVI.

• Routed ports: Routed ports are physical ports configured to be in Layer 3 mode by using the no switchport interface configuration command.

• Layer 3 EtherChannel ports: EtherChannel interfaces made up of routed ports.

A Layer 3 device can have an IP address assigned to each routed port and SVI.

There is no defined limit to the number of SVIs and routed ports that can be configured in a device or in a device stack. However, the interrelationship between the number of SVIs and routed ports and the number of other features being configured might have an impact on CPU usage because of hardware limitations. If the device is using its maximum hardware resources, attempts to create a routed port or SVI have these results:

• If you try to create a new routed port, the device generates a message that there are not enough resources to convert the interface to a routed port, and the interface remains as a switchport.

• If you try to create an extended-range VLAN, an error message is generated, and the extended-range VLAN is rejected.

• If the device is notified by VLAN Trunking Protocol (VTP) of a new VLAN, it sends a message that there are not enough hardware resources available and shuts down the VLAN. The output of the show vlan user EXEC command shows the VLAN in a suspended state.

• If the device attempts to boot up with a configuration that has more VLANs and routed ports than hardware can support, the VLANs are created, but the routed ports are shut down, and the device sends a message that this was due to insufficient hardware resources.

Note

All Layer 3 interfaces require an IP address to route traffic. This procedure shows how to configure an interface as a Layer 3 interface and how to assign an IP address to an interface: If the physical port is in Layer 2 mode (the default), you must enter the no switchport interface configuration command to put the interface into Layer 3 mode. Entering a no switchport command disables and then re-enables the interface, which might generate messages on the device to which the interface is connected. Furthermore, when you put an interface that is in Layer 2 mode into Layer 3 mode, the previous configuration information related to the affected interface might be lost, and the interface is returned to its default configuration