MULTICAST SERVICE
In ReadOne/WriteAll and ReadFirst/WriteAll model, SG load balancer will turn
a unicast request into a multicast request to make it received by all servers
in a server group. We call this kind of service multicast service.
The requirement of a multicast service
- UDP based
- Synchronized request-reply
- Deterministic session handle/key
This guarantees a request has same meaning on all servers
- Unique ID for each pair of request and reply
The service program designer has to implement the packet analyzer API for
its own protocol. A packet analyzer is used by NATD to parse the request/reply
packet of a multicast service, return the unique id of them and check whether
a request is write or not. Currently the packet analyzer for Sun RPC is available.
- Set IP option when making write reply
We provides a set of multicast support routines for service program to return
its write result in the IP option header.
- Update properties on SG
a library of feedback protocol is available for service program to update
properties on SG load balancer.
