Supplement
R&S NRP
1144.1400.12-04- Supplement
2
E-1
VXI11
The VXI11 protocol uses ONC RPC (open network computing remote procedure calls), making it
possible to call R&S NRP functions at the source code level as if they were running locally on the
controller. The following figure shows the relationships of the relevant protocol layers in the OSI
reference model.
A p p l i c a t i o n
V X I 1 1
N e t w o r k I n s t r u m e n t
P r e s e n t a t i o n
X D R ( D a t a r e p r e s e n t a t i o n )
S e s s i o n
O N C R P C
T r a n s p o r t
T C P
N e t w o r k
I P
D a t a L i n k
E t h e r n e t / 8 0 2 . 3
P h y s i c a l
1 0 / 1 0 0 B A S E - T
The VXI11 protocol stack in the OSI reference model
A VXI11 remote-control connection consists of three channels (core, abort and interrupt) which can be
used to set up as many links as desired. The concept of links makes it possible to connect a
network
instrument
client
in a controller with a number of logical measurement
devices
in a host computer via a
single VXI11 remote-control connection. A link is then set up to each logical device. It is also possible to
set up several links to one logical device, provided that several servers are running on the network
instrument host or a network instrument client is being served by several controllers. To prevent
problems caused by several controllers simultaneously accessing one device, links can be locked. A
locked link has exclusive access rights to a particular device. Accesses via other links are then not
possible. An exception is an abort via the abort channel, which can be executed at any time and also
aborts the execution of commands via other links.
C o r e C h a n n e l
A b o r t C h a n n e l
I n t e r r u p t C h a n n e l
L i n k 1
L i n k 2
L i n k n
L i n k 1 , L i n k 2 , L i n k n
N e t w o r k
I n s t r u m e n t
C l i e n t
C o n t r o l l e r
N e t w o r k I n s t r u m e n t H o s t
L i n k 1
L i n k 2
L i n k n
L i n k 1 , L i n k 2 , L i n k n
N e t w o r k
I n s t r u m e n t
S e r v e r
R & S N R P
: N e t w o r k I n s t r u m e n t H o s t
D e v i c e
Diagram of a VXI11 connection with several links
