RPC 6/14/20161BALAJI K - AP

Design issues of RPC Programming with interfaces Call Semantics associated with RPC Transparency and related to procedure calls 6/14/20162BALAJI K - AP

1.Programming with interface Accessed from one module to other module Service provided: – Specify the procedure – Defining the argument type of each procedures Benefits: Abstraction only visible and not the implementation Programmer no need to learn the language 6/14/20163BALAJI K - AP

Interface Definition language (IDE) Allow procedures implemented in different language to invoke one another Ex: Struct person { String name; String place; long year; }; 6/14/20164BALAJI K - AP

interface personlist { readonly attribute string listname; void addperson (in person p); void getperson (in string name,out person p); long number(); } 6/14/20165BALAJI K - AP

2. RPC call semantics Retry request message (wait or assumed ) Duplicate filtering (one or more reply / requests) Retransmission of results (result message) 6/14/20166BALAJI K - AP

May be semantics Procedure execute once or not at all No of fault tolerance measures Type of failure: – Omission failure (request / reply message lost) – Crash failure (server side fails) 6/14/20167BALAJI K - AP

At most once semantics Invoke the semantics atleast once. Type of failure: – Crash failure – Arbitrary failure (resultant value is wrong) At least once semantics Procedure executed exactly once or no result 6/14/20168BALAJI K - AP

3.Transparency Hidden message passing to programmer Access transparency (local and remote procedures) 6/14/20169BALAJI K - AP

Group communication One – One (Unicast) One – One (multicast) Any process can join this group Eg: – Online conferencing Operation: – Join – Leave – Send – Receive 6/14/201610BALAJI K - AP

Characteristics Fault tolerance Finding discovery servers Better performance Propagation of event notification Class D internet address (224 to 239) IP ports (TCP – 20 & 21,UDP - 67, 68 & 69) Implementing IP packet Set of computers 6/14/201611BALAJI K - AP

Publisher publish provide event service Express their interest on particular event Match against events and delivery of event notification Application : Google infrastructure Financial information system Characteristics: Heterogeneity (hardware and software) Synchronicity (simultaneous) Publish subscribe systems 6/14/201612BALAJI K - AP

Programming model of system Channel based Topic based Content based Type based 6/14/201613BALAJI K - AP

Publishers Subscribers Publish adverti se subscri be modify 6/14/201614BALAJI K - AP

Publish: Disseminate an event o Subscribe: o Unsubscribe: o Modify o Advertise o Unadvertised 6/14/201615BALAJI K - AP