User’s Manual of NS3550-24T/4S
483
CDP
CDP is an acronym for
C
isco
D
iscovery
P
rotocol.
D
DEI
DEI is an acronym for
D
rop
E
ligible
I
ndicator. It is a 1-bit field in the VLAN tag.
DES
DES is an acronym for
D
ata
E
ncryption
S
tandard. 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
D
ynamic
H
ost
C
onfiguration
P
rotocol. 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
address or other assignment policies. Specifically the option works by setting two sub-options: Circuit ID (option 1) and
Remote ID (option2). The Circuit ID sub-option is supposed to include information specific to which circuit the request
came in on. The Remote ID sub-option was designed to carry information relating to the remote host end of the circuit.
Summary of Contents for IFS NS3550-24T/4S
Page 1: ...P N 1072569 REV 00 05 ISS 11OCT12 IFS NS3550 24T 4S User Manual ...
Page 37: ...User s Manual of NS3550 24T 4S 37 ...
Page 96: ...96 Figure 4 4 6 Port Mirror Configuration Page Screenshot ...
Page 127: ...User s Manual of NS3550 24T 4S 127 Figure 4 6 10 Port 1 Port 6 VLAN Configuration ...
Page 184: ...184 Figure 4 9 14 Voice VLAN Configuration Page Screenshot ...
Page 204: ...204 Figure 4 11 4 Network Access Server Configuration Page Screenshot ...
Page 234: ...234 Figure 4 12 1 Port Limit Control Configuration Overview Page Screenshot ...
Page 250: ...250 Click to undo any changes made locally and revert to previously saved values ...
Page 297: ...User s Manual of NS3550 24T 4S 297 ...
Page 388: ...388 Example Show RADIUS statistics SWITCH security aaa statistics ...
Page 410: ...410 Parameters vid VLAN ID 1 4095 Default Setting disable ...