Lucent Technologies PortMaster User Manual
Page 323

Glossary
Glossary-13
filter
Generally, a process or device that screens network traffic for certain characteristics, such 
as source address, destination address, or protocol, and determines whether to forward or 
discard that traffic based on the established criteria. 
filter table
A database used to store filters.
Flash RAM
See nonvolatile RAM.
flow control
A technique for ensuring that a transmitting entity, such as a modem, does not 
overwhelm a receiving entity with data. When the buffers on the receiving device are 
full, a message is sent to the sending device to suspend the transmission until the data in 
the buffers has been processed. Flow control can be software-based, or hardware-based.
FRAD
Frame Relay access device. A network device that links any non-Frame Relay connection 
to a Frame Relay WAN.
frame
A packaging structure for network data and control information. A frame consists of a 
destination address, source address, length field, data, padding, and frame check 
sequence. The 802.3 standard for Ethernet specifies that the minimum size data frame is 
64 bytes and the maximum size data frame is 1518 bytes.
Frame Relay
An industry-standard switched data link layer protocol that handles multiple virtual 
circuits using high-level data link layer control (HDLC) encapsulation between connected 
devices. It is used across the interface between user devices (for example, hosts and 
routers) and network equipment (for example, switching nodes). Frame Relay is more 
efficient than X.25, the protocol it replaced.
Frame Relay access device
See FRAD.
FTP
File Transfer Protocol. A TCP/IP protocol used to transfer files between network hosts.
