This chapter contains the following sections:
Information About Interfaces
All interfaces on the Cisco Nexus 1000V are Layer 2 Ethernet interfaces, which include access ports, trunk ports, private VLAN ports, and promiscuous ports.
An access port carries traffic for one VLAN. This type of port is a Layer 2 interface only.
Private VLAN Ports
Private VLANs (PVLANs) are used to segregate Layer 2 ISP traffic and convey it to a single router interface. PVLANs achieve device isolation by applying Layer 2 forwarding constraints that allow end devices to share the same IP subnet while being isolated by Layer 2. The use of larger subnets reduces address management overhead. Three separate port designations are used. Each has its own unique set of rules that regulate the ability of each connected endpoint to communicate with other connected endpoints within the same PVLAN domain.
For more information about PVLANs, see the Cisco Nexus 1000V Layer 2 Switching Configuration Guide
A promiscuous port can talk to all other types of ports. A promiscuous port can talk to isolated ports as well as community ports, and those ports can also talk to promiscuous ports.
For more information about promiscuous ports, see the Cisco Nexus 1000V Layer 2 Switching Configuration Guide .
A trunk port carries traffic for two or more VLANs. This port type is a Layer 2 interface only.
Virtual Ethernet Interfaces
Virtual Ethernet (vEthernet or vEth) interfaces are logical interfaces. Each vEthernet interface corresponds to a switch interface that is connected to a virtual port. The interface types are as follows:
- VM (interfaces connected to VM NICs)
- Service console
vEthernet interfaces are created on the Cisco Nexus 1000V to represent virtual ports in use on the distributed virtual switch.
You can use the management Ethernet interface to connect the device to a network for remote management using a Telnet client, the Simple Network Management Protocol (SNMP), or other management agents.
Port Channel Interfaces
A port channel is a logical interface that aggregates multiple physical interfaces. You can bundle up to eight individual links to physical ports into a port channel to improve bandwidth and redundancy. You can also use port channeling to load balance traffic across these channeled physical interfaces.
VEM Management of LACP
You can offload operation of the Line Aggregation Control Protocol (LACP) from the VSM to the VEMs to prevent a situation where LACP cannot be negotiated with the upstream switch when the VEM is disconnected from the VSM (referred to as headless mode). VEM management of LACP allows port channels to be reestablished after the reboot of a headless VEM.
Simplifying the Interface Configuration with Port Profiles
You can use a port profile to simplify the interface configuration. You can configure a port profile and then assign it to multiple interfaces to give them all the same configuration. Changes to the port profile are propagated to the configuration of any interface that is assigned to it.
We do not recommend that you override port profile configurations by making changes to the assigned interface configurations. You should make configuration changes to interfaces only to quickly test a change or to disable a port.
High Availability for Interfaces
Interfaces support stateful and stateless restarts. A stateful restart occurs during a supervisor switchover. After the switchover, the Cisco Nexus 1000V applies the run-time configuration.