Which of the following are ways that Cisco VIC adapters can communicate? (Choose three.)
- by using cut-through switching
- by using store-and-forward switching
- by using a bare-metal OS driver
- by using pass-through switching
- by using software and a Nexus 1000v
Cisco virtual interface card (VIC) adapters support three communication methods: by using software and a Cisco Nexus 1000v virtual switch, by using pass-through switching, and by using a bare-metal operating system (OS) driver. Cisco VICs integrate with virtualized environments to enable the creation of virtual network interface cards (vNICs) in virtual machines (VMs). Traffic between VMs is controlled by the hypervisor when using software and a Cisco Nexus 1000v virtual switch. Cisco describes the software-based method of handling traffic by using a Cisco Nexus 1000v virtual switch as Virtual Network Link (VN-Link).
Pass-through switching, which Cisco describes as hardware-based VN-Link, is a faster and more efficient means for Cisco VIC adapters to handle traffic between VMs. Pass-through switching uses application-specific integrated circuit (ASIC) hardware switching, which reduces overhead because the switching occurs in the fabric instead of relying on software. Pass-through switching also enables administrators to apply network policies between VMs in a fashion similar to how traffic policies are applied between traditional physical network devices.
Cisco VIC adapters forward traffic similar to other Cisco Unified Computing System (UCS) adapters when installed in a server that is configured with a single bare-metal OS without virtualization. It is therefore possible to use a Cisco VIC adapter with OS drivers to create static vNICs on a server in a nonvirtualized environment.
Cisco VIC adapters do not communicate by using store-and-forward switching. However, switches can be configured to use store-and-forward switching. A switch that uses store-and-forward switching receives the entire frame before forwarding the frame. By receiving the entire frame, the switch can verify that no cyclic redundancy check (CRC) errors are present in the frame; this helps prevent the forwarding of frames with errors. Cisco VIC adapters are hardware interface components that support virtualized network environments.
Cisco VIC adapters do not communicate by using cut-through switching. The cut-through switching method is a switch forwarding method that begins forwarding a frame as soon as the frame’s destination address is received, which is after the first six bytes of the packet are copied. Thus the switch begins forwarding the frame before the frame is fully received, which helps reduce latency. However, with the cut-through method, the frame is not checked for errors prior to being forwarded.