CCNA Quick Reference Sheets (CCNA Exam 640-802)

Section 2. Redundant Switching and STP

Redundant Switched Topology Issues

A redundant topology has multiple connections to switches or other devices. Redundancy ensures that a single point of failure does not cause the entire switched network to fail. In the absence of the Spanning Tree Protocol (STP), Layer 2 redundancy can cause problems in a network, including broadcast storms, multiple copies of frames, multiple loops, and MAC address table instability. Figure 2-1 shows a redundant topology.

Figure 2-1. Redundant Switched Topology

Broadcast Storms

The flooding of broadcast frames can cause a broadcast storm (indefinite flooding of frames) ...