Winmate Inc. 1200 Benutzerhandbuch

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42 

 
This section explains some of the simple network concepts concerning wireless 
LAN’s and networking in general. 
 
Topics covered are: 

 

Packet Fragmentation

 

 

Encryption

 

 

Subnetting

 

 

 
Packet fragmentation means splitting a data packet into several smaller packets.   
We need to fragment packets because of: 

o  Hardware limits – some hardware do not support packets up to certain 

threshold. 

o  Operating system buffer constraints – depending on the system memory, 

buffer overflow means lost of data and waste bandwidth in unnecessary 
retransmissions. Breaking packets into smaller segment means system will 
have extra memory and extra time in processing those smaller data packets. 

o  Protocol limits – some protocol specify maximum permitted size of a packet. 

E.g. an ATM cell packet is restricted to 53 bytes. 

o  Reduce channel occupancy – routers can process smaller packets faster than 

larger packets, result in smaller packet stays in router shorter time. This will 
result in more throughputs and reduce the likelihood router dropping packets. 

 
Advantages of packet fragmentation: 

  Easier and faster processing time for routers. 
  Less delay compare to larger packets 
  Less likelihood of routers dropping packets when traffic in network is heavy. 

This is because the processing time for fragmented packets is lower. 

 
Disadvantages for packet fragmentation: 

  Additional header information in the packet header result in less data can be 

stored in a single packet. 

  Unnecessary packet fragmentation if traffic in network is low. 
  Reassemble fragmented packets requires extra time.