User guide

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buffers approach capacity, the modem signals the computer to stop while it
catches up on processing the data in the buffer. See CTS, RTS, xon/xoff.
fragmentation. Process of breaking a packet into smaller units so that they
can be sent over a network medium that cannot transmit the complete
packet as a unit.
frame. Logical grouping of information sent as a link-layer unit. Compare
datagram, packet.
FTP. File Transfer Protocol. Application protocol that lets one IP node trans-
fer files to and from another node.
FTP server. Host on network from which clients can transfer files.
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Hard MBytes. Setting the Hard MBytes parameter forces the renegotiation
of the IPSec Security Associations (SAs) at the configured Hard MByte value.
The value can be configured between 1 and 1,000,000 MB and refers to
data traffic passed.
Hard Seconds. Setting the Hard Seconds parameter forces the renegotia-
tion of the IPSec Security Associations (SAs) at the configured Hard Seconds
value. The value can be configured between 60 and 1,000,000 seconds.
A tunnel will start the process of renegotiation at the soft threshold and
renegotiation must happen by the hard limit or traffic over the tunnel is ter-
minated.
hardware handshake. Method of flow control using two control lines, usu-
ally Request to Send (RTS) and Clear to Send (CTS).
header. The portion of a packet, preceding the actual data, containing
source and destination addresses and error-checking fields.
HMAC. Hash-based Message Authentication Code