Added support for CDP and EDP in the latest NetTool and LinkRunner, which will greatly improve the network status information provided to users during fault diagnosis. CDP is the abbreviation of Cisco Discovery Protocol; EDP is the abbreviation of Extreme Discovery Protocol. This article describes the use of CDP and EDP protocols and the information available from LR and NT during network diagnostics.
Technical Background:
Many network management software use the "Automatic Discovery" function to track topology changes and conditions. However, most software only reaches the third layer at most, and the device is directed to the route table/ARP table, groups IP subnets. However, topology discovery on the second layer is quite lacking, but it is an important information for Fault Diagnosis: for example, the path in which the switch and other devices connect to each other, displays the relative positions of clients, switches, routers, and servers. This feature already has good solutions in Optiview and ES network products of fluke networks, such as Trace SwitchRoute.
Device vendors have released their own proprietary protocols for managing layer 2 network conditions, such as Cisco's CDP Protocol Cisco Discovery Protocol) and Extreme Networks's EDP Protocol Extreme Discovery Protocol) enterasys Networks's CDP Protocol Cabletron Discovery Protocol) and Nortel Networks's NDP Protocol Nortel Discovery Protocol. CDP developed by Cisco is widely used in CISCO products.
CDP Cisco Discovery Protocol
Cisco Discovery Protocol CDP is basically used to obtain Protocol addresses of adjacent devices and platforms for discovering these devices. CDP can also provide related interface information for vro use. CDP is an independent media protocol that runs on all devices manufactured by Cisco, including routers, bridges, access servers, and switches.
Each device configured with CDP sends periodic information, including the lifetime or retention time. Each device also pays attention to the periodic CDP information sent by other devices to learn information about adjacent devices. CDP version 2 is the most widely used version of this Protocol. It has higher smart device tracking performance.
CDP is a convenient Fault Diagnosis tool that allows you to easily determine the direction of a fault. It is a typical troubleshooting tool in the fault diagnosis method. IOS provides comprehensive information about neighboring devices. It is the result of executing show cdp neighbor detail on a network device. The broadcast information of CDP includes the device name, IP address, Local interface number, device type, IOS version, product model, and interface number of the neighboring device. The EDP Principles and Methods of Extreme are basically the same as those of CDP.
CDP and EDP are the information of the adjacent devices advertised by the vswitch and vro. After receiving the information, the neighboring devices will not broadcast the information to other devices. However, devices of different vendors broadcast and forward these packets because they do not recognize CDP or EDP.
NetTool and LinkRunner support CDP and EDP protocols
According to NetTool's analysis on CDP protocol, the port information of the switch with the closest connection to NT and supporting CDP is obtained, as shown in:
NetTool reports that the network device is a Cisco Catalyst 2950 T, 24-port switch named 2950T-GIG. The management IP address is 10.196.197.149, the port number is FastEthernet0/8, and is in vlan1. This means that the PC Connected to NetTool is located in VLAN1. If there are only Cisco devices in the network, the port connecting to the PC is FastEthernet0/8. Or, there may be other hubs or non-Cisco switches between 2950T-GIG and PC.
You can also obtain port information for LR, including IP address (10.196.197.151), MAC address (Cisco-2950), and the port number (FastEthernet0/2) of the LR peer ).
If the switch does not enable or does not support CDP, a prompt is displayed.
