Common protocols for cisco switches

There are three switch modes: storage forwarding, fast forwarding, and segmented forwarding.
1. CSMA/CD (Multi-Channel Access for carrier listeners with conflict detection)
Working principle: Listen to whether the channel is idle before sending. If it is idle, send it immediately. When sending the message, listen to it. If there is a conflict, immediately stop sending and wait for a random period of time, resend.
2. CDP: When a cisco device is started, CDP is automatically started, and the network administrator can obtain summary information about the directly connected device. CDP runs on the data link layer.
3. relay link: the trunk virtual link, which is a universal 802.1q (Virtual bridging LAN Standard) for global devices ).
4. DTP (dynamic relay Protocol): cisco proprietary protocol, which can only be used for relay links at the vswitch and vro fingertip, and supports automatic negotiation between ISL and 802.1q.
5. BPDU (data unit of the Bridge Protocol) are used by the Spanning Tree Algorithm to determine the information of the network topology and exchange the bridge ID and root path cost.
6. VTP Protocol: A Message Protocol that uses layer-7 frames to manage vlan addition, deletion, and rename on the basis of the entire network to achieve consistent vlan configuration.
7. STP (spanning tree protocol) Logically disconnects the network loop to prevent the generation of broadcast storms. Once a faulty line is in use, the logically disconnected line is connected again to continue data transmission.
8. PVST: runs a separate Spanning Tree Protocol instance for each virtual LAN, which has the role of Server Load balancer.

 

This article is from "fingertip white profiling"