protocol testing is testing the performance and evaluate 
it in  working conditions

for wireless i have tried GlomoSim simulator, as it has
ability to test 100 nodes on single cpu and for thousands of
nodes multiprocessor and parallel version is reqd.

doegar

Protocol testing to find that protocol request /resposnse 
working properly your produt and to test performance 
that it

communication between two vendors(different product makers)is
done via the protocol messages based on international
standards.to check that we've to use the tools which
supports and generate the protocol messages.
I've used the tools..,
1)abacus 5000>>>>SIP,ISUP,H248
2)MGTS-ISUP protocol messages

Protocol testing is the testing the protocol's 
functionality. Any given protocol should function accordin 
to its RFC. Protcol testing involves testing functionality, 
protocol stack, interoperability, performance etc... 
I have tested SIP protocol using Ethereal tool. Ethereal is 
used to capture protocol packets and to analyze them. Some 
other tools we can use are Etherpeek, abacus 5000, Nethawk. 
Wireshark etc..

Protocol testing means to test the functionality of the
node(piece of software) which should compliance to some
standard message flow. For this one should take a
tester(Testing Unit) which should send standard messages to
the node(Item under test). Above all tester mentioned are
good but according to me K1297-G20(Tektronics)is the best
tester.
Advantages
1) Many standard Protocol are supported by this tester
2) One can add just new protocol supports easily
3) With introduction of G-20 its interface is really good,
one can easily learn.

Disadvantages
1) Load can't be tested with this, as this tester is windows
based with low processing capabilities
2) It is little bit costly as it give license per link per
protocol base
3) Support too have some issues
 
I think because of its high cost small companies don't use
it and also big shots doesn't have enough number K1297-G20

Protocol testing ensures proper functionality of various
elements of a message. It also ensures whether it has
designed as per specification.
   When we are talking about protocol testing then we must
be aware of two tools. i.e. Analyser and Simulator. Job of
analyser to ensures proper decoding along with Call and
session analysis. Job of simulator is to simulate various
entities of networking element.
e.g. In GSMA interface we may simulate BSC, where the system
under test may be MSC.
I ve used 
NetHawk EAST simulator 
Analyser: 
NetHawk M5,RADCOM, WIRESHARK etc.

Protocol testing is a big picture of compliance to 
Standards of IETF/RFC(request for Comments). Each protocol 
have defined actions for its functionality provided by a 
number. The standards are set and agreed upon by many 
engineers using internet. 
If any product is using this standatrds in their devices 
they are interopble with other vendor devices as both are 
meeting standards. For network protocols IXIA is the best 
tool for this compliance testing.

Protocol testing is usually used in companies working in the development and testing of communication devices, for example cisco, juniper, alcatel ... are working on the development of routers ,switches and other networking devices, here protocol testing means testing of routing and switching protocols, companies working in telecom domain, wireless domain,security domain may also do their respective protocol testing.

In generic protocol testing means the verification of the different rules mentioned in the protocol standard. This may be  checking the protocol packet structure, their algorithm ,different features supported or it may be interoperability or performance of the protocol ,

you may try http://www.zframez.com for some more detailed information about protocol testing.