FEC (Forward Error Correction) is a very effective method to minimize radio channel impairments.
Basically the sender inserts some redundant data into its messages. This redundancy allows the re-
ceiver to detect and correct errors (to some extent). The improvement comes at the expense of the
user data rate. The lower the FEC ratio, the better the capability of error correction and the lower the
user data rate. The User data rate = Modulation rate x FEC ratio.
Optimization*
List box: On, Off
Default = Off
Optimization is applicable in Router mode for packets directed to Radio channel. It watches packets
on individual radio links and optimizes both the traffic to the counterpart of a link and the sharing of the
Radio channel capacity among the links.
On an individual link the optimizer supervises the traffic and it tries to join short packets when oppor-
tunity comes. However in case of heavy load on one link (e.g. FTP download) it splits the continuous
stream of packets and creates a window for the other links. To minimize the actual load, Zlib compression
(with LZ77 decimation and Huffman coding) and other sophisticated methods are used.
In addition a special TCP optimiser is used for TCP/IP connections. It supervises every TCP session
and eliminates redundant packets. It also compresses TCP headers in a very efficient way. The overall
effect of the Optimization depends on many factors (data content, packet lengths, network layout etc.),
the total increase of network throughput can be anything from 0 to 200%, or even more in special cases.
Note
: Apart from this Optimization, there is an independent compression on the Radio channel, which
works in both Operating modes, Bridge and Router. This compression is always On.
Encryption
AES 256 (Advanced Encryption Standard) can be used to protect your data from an intrusion on Radio
channel. When AES 256 is On, control block of 16 Bytes length is attached to each frame on Radio
channel. AES requires an encryption key. The length of key is 256 bits (32 Bytes, 64 hexa chars). The
same key must be stored in all units within the network.
List box: Off, AES 256
Default = Off
When AES 256
Key mode
List box: Pass Phrase, Manual
Default = Pass Phrase
•
Pass phrase
It is not necessary to fill in 32 Bytes of hexa chars in order to set the encryption key. The key can
be automatically generated based on a Pass phrase. Fill in your Pass phrase (any printable ASCII
character, min. 1 char., max. 128 char.). The same Pass phrase must be set in all units within the
network
•
Manual
The key can be configured manually (fill in 32 Bytes of 64 hexa chars) or it can be randomly generated
using Generate button. The same key must be in all units within the network, i.e. it has to be gener-
ated only in one unit and copied to the others.
MTU [bytes]*
Default = 1500 Bytes [70 - 1500] (max. packet size)
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© RACOM s.r.o. – RipEX Radio modem & Router
Advanced Configuration
Содержание RipEX 1.5
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