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Implementing Remote Procedure Calls
Andrew Birrell and Bruce Nelson
Presented by
Conventional Procedure Calls
main proc1 proc5 proc2 proc3 proc4 proc6 proc7 proc8
Implementing Remote Procedure Calls Andrew Birrell and Bruce Nelson - - PowerPoint PPT Presentation
Implementing Remote Procedure Calls Andrew Birrell and Bruce Nelson - - PowerPoint PPT Presentation
Implementing Remote Procedure Calls Andrew Birrell and Bruce Nelson Presented by Kai Cong Conventional Procedure Calls main proc 1 proc 2 proc 3 proc 4 proc 5 proc 6 proc 7 proc 8 Within a program on a single computer!!! Extension of the
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Extension of the Procedural Model
main proc1 proc5 proc2 proc3 proc4 proc6 proc7 proc8
computer1 computer2 across a netWork betWeen programs
- n different computers!!!
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4
Remote Procedure Call (RPC)
Client Server Computing Blocked Blocked Blocked
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RPC – How it works
client
procedure call
client stub
locate (un)marshal (de)serialize send (receive)
server
procedure
server stub
(un)marshal (de)serialize receive (send)
client process server process RPC Runtime module RPC Runtime module
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Issues
- Binding
- Passing data
- Implementation
- Exceptions
- RPC systems
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- The binding operation is to bind an importer
- f an interface to an exporter of an interface.
- After binding, calls made by the importer
invoke procedures implemented by the remote exporter.
- static binding vs dynamic binding
Binding
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- static binding(not presented by the paper)
– hard coded stub – simple – efficient – not flexible – stub recompilation is necessary if the location
- f the server changes
– use of redundant servers is not possible
Static Binding
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- dynamic binding
– Interface: type and instance – Database
- load balancing
– flexible – redundant servers is possible
Dynamic Binding
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client
procedure call
client stub
bind (un)marshal (de)serialize find send receive
RPC Runtime module
server procedure server stub
register (un)marshal (de)serialize receive send
client process server process
Database
2 4 5 6 7 1 3
Dynamic Binding
RPC Runtime module
7
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Issues
- Binding
- Passing data
- Implementation
- Exceptions
- RPC systems
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Passing Data
- Can't use the stack!
- Can't use shared memory!
- Generally use message passing
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Passing data
Build a message that includes:
- Who and what's being called
- Identity of the caller
- Data values in known byte order
- Using an intermediate data representation
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Issues
- Binding
- Passing data
- Implementation
- Exceptions
- RPC systems
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Implementation
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Implementation
- Function prototype is (almost) all that's
needed to build the client stub
– Also need binding information
- Function prototype is (almost) all that's
needed to build server stub
– Also need method to wait for message
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Implementation
- Stub compiler
– Generates stubs for client and server – Language dependent – Compile into machine-independent format
- Transport protocol
– PUP, XML, SOAP, DCOM, CORBA, …
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Implementation
Clients
Threaded
Servers
Event Driven
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Issues
- Binding
- Passing data
- Implementation
- Exceptions
- RPC systems
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- What can happen in "normal" procedures?
– Procedure generates an exception – Procedure infinite loops – Procedure generates wrong results
Exceptions
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Exceptions
- What can happen in "remote" procedures?
– Client stub generates an exception – Transmission failure
- knowable failure
- unknowable failure
– Remote procedure generates an exception – Remote procedure infinite loops – Remote procedure generates wrong results
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Issues
- Binding
- Passing data
- Implementation
- Exceptions
- RPC systems
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RPC Systems
- Sun RPC
- DCE RPC
- DCOM
- CORBA
- Java RMI
- XML RPC, SOAP/.NET, AJAX, REST
- Protocol Buffers (Google)
- Thrift (Facebook)
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Conclusion
- Remote Procedure Call should look and feel
like local call
- Remote Procedure Call should be independent
- f where it executes
- Remote Procedure Call should be "efficient“