Archive for the ‘HP’ Category

Discovery Protocols on Cisco, HP, and Force10 Switches/Routers – CDP and LLDP

Saturday, April 23rd, 2011

The Cisco Discovery Protocol (CDP) is a Cisco proprietary Data Link Layer network protocol used to share information about other directly connected Cisco equipment. CDP can also be used in place of dynamic routing protocols in simple networks. Cisco devices send CDP announcements out each connected network interface to the multicast destination address 01-00-0C-CC-CC-CC. By default CDP announcements are sent every 60 seconds. The “show cdp neighbors” command that you are probably familiar with basically displays stored information that has been collected from other devices. Further, the CDP data is also accessible via snmp. The holdtime, which specifies the lifetime of an entry in the table, by default is 180 seconds. (more…)