1.10. Glossary

This section summarizes the terminology used in the Pia library. The same terminology may be used with different meanings in other documents.

Session Terminology

Glossary Description
Session Where a group of players are playing a game together. Sessions comprise the matchmaking session for the group on the server (or a local communication network) and a P2P mesh network for P2P communications.
Station (member) A device (player) participating in a session.
Session host The one station in a session that has session administrator privileges.
Client (session client)

All stations within the session other than the session host.
To make a distinction from the session host, the term session client is sometimes used.

Host migration

The process that transfers the role of the session host to one of the remaining stations when the session host leaves the session.
Matchmaking session (gathering) The session for a group of players that is hosted on the matchmaking server. In some cases, the matchmaking session is added to the matchmaking server before the players are connected to the P2P mesh network.

Mesh (P2P mesh network)

A P2P network created between stations in a session. Stations may be connected to the P2P mesh network directly or through another one of the stations in the session.

Network Topology The type of topology used to construct the P2P mesh network. For example, a full mesh network topology is used when all stations need to be able to communicate with each other directly. There are various other types of network topologies.

Communication Network Terminology

Glossary Description
Node A device connected to a network.
Link A connection between two nodes. In most cases, indicates a communication route over which two nodes can directly exchange data.
Network A communication network comprising multiple links.
Internet Has the same meaning as the generally used "Internet."
LAN A local IP network such as a home-based LAN or a wireless LAN.
UDS Network

A local network using UDS communications, a proprietary Nintendo communications format.

Internet Communication Terminology

Glossary

Description

Gateway Indicates a device that forms a bridge between a network (such as a LAN) and a network (such as the Internet). The wireless router used to access the Internet on a wireless LAN is a good example of a gateway.
NAT Network address translation. The IP address (and port number) conversion process performed when a gateway accesses the Internet from a LAN.
NAT Traversal The process and algorithm used to communicate with a console isolated by a network address translation.
MTU Maximum transmission unit. The maximum size value of data that can be sent during a single transmission over a communication network.

Data Communication-Specific Terminology

Glossary Description
Packet A piece of data sent and received over a network.
It comprises a header and a payload (the actual data portion).
Payload Indicates the actual data portion of what is usually a packet.
Unreliable Communication A communication method in which the send data is not guaranteed to be delivered to the send target.
Generally speaking, more data is exchanged using unreliable communication than with reliable communication. (Example: UDP.)
Reliable Communication A communication method in which the send data is guaranteed to be delivered to the send target.
When using reliable communication, there is no need to consider what to do when data does not arrive at the target (for example, TCP).
Note: Data does not reach the recipient if the recipient has left the session or if there is no response from the recipient for a prolonged period.
Unicast Indicates the sending of data to a specified single station.
Broadcast Indicates the sending of data to all stations other than the local device.
Latency Indicates the time from the start of the data's sending until that data is received by the other party (latency). (See Figure 1-1. Differences Between Latency and RTT.)
In general, latency is lower for local communication and higher for Internet communication.
RTT
(Round Trip Time)
Indicates the time needed for the following series of processes.
1. Some data is sent from station A to station B;
2. The data is received at station B and processed, and the results are returned to station A;
3. Station A receives the response from station B.
RTT has nearly the same definition as "round-trip latency," and in theory, it is just over twice the latency.
Jitter Latency and RTT scattering.
Note: The delay time for communication is not fixed. It changes in response to various factors.
Figure 1-1. Differences Between Latency and RTT

Pia Process Classification Terminology

Glossary Description
Initialization Processing handled by the Initialize()- and CreateInstance()-type functions.
It may involve allocating memory from the space allocated to the Pia library.
Startup Processing handled by the Startup() function.
Executed after initialization, this process puts the object into a usable state. This process does not allocate or deallocate memory.
Cleanup Processing handled by the Cleanup() function.
The opposite of the startup process, this process puts the object into an unusable state. This process does not allocate or deallocate memory.
Finalization Processing handled by the Finalize()- and DestroyInstance()-type functions.
The opposite of the initialization process, this process may involve deallocating the memory secured in initialization.