Cisco Systems 5.2.x Auto Smartports macro to run automatically, An optional Dhcp relay class that

Chapter 11 Register DMPs

Concepts

C	Return to Top
CDP	Cisco Discovery Protocol. DMPs and other devices that support CDP can communicate facts about
	themselves, amongst themselves, over any physical network medium that supports Subnetwork Access
	Protocol (SNAP) encapsulation. CDP uses the data link layer, which connects physical network media
	to upper-layer protocols. And because CDP operates at this level, two or more CDP devices that support
	different network layer protocols (for example, IP and Novell IPX) can learn about each other.
	Specifically, CDP causes devices to advertise not only their existence, but also their platform types,
	protocols, IP addresses, and SNMP-agent addresses to neighboring devices on their LAN switch or
	WAN. And when their connected switch is Medianet-ready, device identification can also trigger an
	Auto Smartports macro to run automatically.
	Thus, CDP facilitates discovery — by network management applications — of Cisco devices that are
	neighbors of known devices. And this is particularly useful when such previously undiscovered
	neighbors use lower-layer, transparent protocols. After they possess information about such devices,
	network management applications can send SNMP queries to them.
	In addition, CDP detects native VLAN and port duplex mismatches.
D	Return to Top
DHCP	Dynamic Host Configuration Protocol. A standard method for devices to request, and servers to
	allocate, IP addresses in a network without human intervention.
DHCP option 125	An optional DHCP relay class that:
	• Injects “vendor-identifying, vendor-specific information” into the request (within a DHCP
	DISCOVER message) to receive a dynamic IP address.
	• Identifies the type of client sending the DHCP DISCOVER message.
	In turn, a DHCP server that is configured to support Option 125 can relay the client-generated request
	to some other DHCP server. This mechanism allows an organization to designate DHCP servers for
	clients that meet particular criteria. For example, you might want all of your DMPs to receive their
	IP addresses from a DHCP server that you reserve for this purpose exclusively.

	User Guide for Cisco Digital Media Manager 5.2.x
OL-15762-03		11-3