User's Manual

User’s Manual of MGSW-MGSD Series
CCM
CCM is an acronym for Continuity Check Message. It is a OAM frame transmitted from a MEP to it's peer MEP and
used to implement CC functionality.
CDP
CDP is an acronym for Cisco Discovery Protocol.
D
DEI
DEI is an acronym for Drop Eligible Indicator. It is a 1-bit field in the VLAN tag.
DES
DES is an acronym for Data Encryption Standard. It provides a complete description of a mathematical algorithm for
encrypting (enciphering) and decrypting (deciphering) binary coded information.
Encrypting data converts it to an unintelligible form called cipher. Decrypting cipher converts the data back to its
original form called plaintext. The algorithm described in this standard specifies both enciphering and deciphering
operations which are based on a binary number called a key.
DHCP
DHCP is an acronym for Dynamic Host Configuration Protocol. It is a protocol used for assigning dynamic IP
addresses to devices on a network.
DHCP used by networked computers (clients) to obtain IP addresses and other parameters such as the default
gateway, subnet mask, and IP addresses of DNS servers from a DHCP server.
The DHCP server ensures that all IP addresses are unique, for example, no IP address is assigned to a second client
while the first client's assignment is valid (its lease has not expired). Therefore, IP address pool management is done
by the server and not by a human network administrator.
Dynamic addressing simplifies network administration because the software keeps track of IP addresses rather than
requiring an administrator to manage the task. This means that a new computer can be added to a network without the
hassle of manually assigning it a unique IP address.
DHCP Relay
DHCP Relay is used to forward and to transfer DHCP messages between the clients and the server when they are not
on the same subnet domain.
The DHCP option 82 enables a DHCP relay agent to insert specific information into a DHCP request packets when
forwarding client DHCP packets to a DHCP server and remove the specific information from a DHCP reply packets
when forwarding server DHCP packets to a DHCP client. The DHCP server can use this information to implement IP
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