UCS Switch Mode: Statements and Configuration | CCIE Data Center Exam Preparation

UCS Switch Mode

Question

Which two statements about UCS switch mode are true? (Choose two.)

Answers

Explanations

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A. B. C. D. E.

Explanation.

UCS switch mode refers to the Ethernet switching mode of the fabric interconnects in a Cisco Unified Computing System (UCS). This mode determines how traffic is handled between servers, between servers and the fabric interconnects, and between the fabric interconnects and the network.

The two true statements about UCS switch mode are:

A. Disjoint Layer 2 networks are supported only when the Ethernet switching mode of the fabric interconnects is configured for switch mode. In UCS, disjoint Layer 2 networks are those in which different sets of servers cannot communicate with each other directly, even though they are connected to the same fabric interconnects. In switch mode, UCS supports disjoint Layer 2 networks by creating a separate bridge domain for each set of servers that cannot communicate with each other. The fabric interconnects use VLANs to separate traffic for each bridge domain.

B. Server-to-server multicast and broadcast traffic is sent through all uplink ports in the same VLAN. In switch mode, when a server sends multicast or broadcast traffic to other servers in the same VLAN, the traffic is forwarded through all uplink ports in that VLAN. This ensures that all servers receive the traffic, regardless of which uplink port they are connected to.

The other options are false:

C. Broadcast packets flood out of all ports except the port that it was received on. In switch mode, broadcast packets are flooded out of all ports in the same VLAN, including the port that received the broadcast packet.

D. Switch mode is the default Ethernet switching mode. The default Ethernet switching mode in UCS is end-host mode, not switch mode.

E. Ethernet switching mode must be used only if the fabric interconnect is connected directly to a router. Ethernet switching mode can be used when the fabric interconnects are connected to a switch or a router. It is not mandatory to use Ethernet switching mode only when the fabric interconnects are connected directly to a router.