
 
 HUT Comms.
 Lab, Timo O. Korhonen
 
 
 
  
  
  
  
  
  
 Practical network
 stratums
 nOSI is seldom
 realized as
 itself but several layers are
 melted
 together into stratums
nIn this example
 X.25 packet
 network operates on ATM
  based SDH access stratums.
nATM forms an efficient
 info pipe where
 no
 address checking or
 error
 correction is done
 but it is left for
 lower
 layers
 n
  
 
  
  
   
   
   
   
   
   
   
   
   
   
   
   
  
  
  
 
  
 