The EGS7228P supports the iEEE 802.1AB Link Layer Discovery Protocol
(LLDP) not the CDP since the LLDP is a vendor-neutral link layer protocol
unlike CDP which is proprietary for Cisco. 

Link Layer Discovery Protocol (LLDP) is the IEEE 802.1AB standard for
Switches to advertise their identity, major capabilities, and neighbors on
the 802 LAN. LLDP allows users to views the discovered information to
identify system topology and detect faulty configurations on theLAN. LLDP
is essentially a neighbor discovery protocol that uses Ethernet
connectivity to advertise information to devices on the same LAN and store
information about the network. The information transmitted in LLDP
advertisements flow in one direction only; from one device to its
neighbors. This information allows the device to quickly identify variety
of other devices, resulting in a LAN that interoperates smoothly and

LLDP transmits information as packets called LLDP Data Units
(LLDPDUs). A single LLDP Protocol Data Unit (LLDP PDU) is transmitted
within a single 802.3 Ethernetframe. A basic LLDPDU consists of a set of
TypeLength-Value elements (TLV), each of which contains information about
the device. A single LLDPDU contains multiple TLVs. TLVs are short
information elements that communicate complex data. Each TLV advertises a
single type of information.