Cisco Discovery Protocol (CDP) Statistics on the 200/300 Series Managed Switches

Objectives

Cisco Discovery Protocol (CDP) is a Link-Layer Cisco proprietary protocol that allows Cisco devices to communicate regardless of IP connectivity. It is used primarily to communicate protocol addresses and device capabilities. CDP sends frames containing Type Length Values (TLVs), which are fields containing different properties of the port and/or connection.

The article explains the information on the CDP Statistics page of the 200/300 Series Managed Switches.

Applicable Devices

• SF/SG 200 and SF/SG 300 Series Managed Switches

Software Version

• v1.2.7.76

CDP Statistics

Step 1. Log in to the web configuration utility and choose Administration > Discovery - CDP > CDP Statistics. The CDP Statistics page opens:

Step 2. Click the radio button next to the desired time interval in the Refresh Rate field to set how often the information below is refreshed.

The CDP statistics information is displayed in the following fields:

• Received — Displays statistics for the number of CDP packets received.

– Version 1 — The number of Version 1 CDP packets the switch has received.

– Version 2 — The number of Version 2 CDP packets the switch has received. Version 2 packets contain more information about the neighbor than Version 1 packets, such as the duplex status of the neighbor connection (Half or full duplex), the power consumption, and an error detection mechanism which provides faster error lookup in the connection with the neighbor device.

– Total — The total number of CDP packets the switch has received.

• Transmitted — Displays statistics for the number of CDP packets transmitted.

– Version 1 — The number of Version 1 CDP packets the switch has transmitted.

– Version 2 — The number of Version 2 CDP packets the switch has transmitted.

– Total — The total number of CDP packets the switch has transmitted.

• CDP Error Statistics — Displays the number of CDP errors by type.

– Illegal Checksum — The number of CDP packets with a bad checksum. This means the packet has been corrupted.

– Other Errors — The number of CDP packets that have errors other than illegal checksum. This is usually due to a mismatch in TLV types being transmitted.

– Neighbors Over Maximum — The number of CDP packets that have been dropped due to lack of memory.

Step 3. (Optional) To clear the CDP Received and Transmitted counters, click Clear Counters.