In computer networking, a network service is an appwication running at de network appwication wayer and above, dat provides data storage, manipuwation, presentation, communication or oder capabiwity which is often impwemented using a cwient-server or peer-to-peer architecture based on appwication wayer network protocows.
Each service is usuawwy provided by a server component running on one or more computers (often a dedicated server computer offering muwtipwe services) and accessed via a network by cwient components running on oder devices. However, de cwient and server components can bof be run on de same machine.
Cwients and servers wiww often have a user interface, and sometimes oder hardware associated wif it.
Exampwes are de Domain Name System (DNS) which transwates domain names to Internet protocow (IP) addresses and de Dynamic Host Configuration Protocow (DHCP) to assign networking configuration information to network hosts. Audentication servers identify and audenticate users, provide user account profiwes, and may wog usage statistics.
Oder network services incwude:
- Directory services
- Fiwe sharing
- Instant messaging
- Onwine game
- Fiwe server
- Voice over IP
- Video on demand
- Video tewephony
- Worwd Wide Web
- Simpwe Network Management Protocow
- Time service
- Wirewess sensor network
|Internet protocow suite|
In computer network programming, de appwication wayer is an abstraction wayer reserved for communications protocows and medods designed for process-to-process communications across an Internet Protocow (IP) computer network. Appwication wayer protocows use de underwying transport wayer protocows to estabwish host-to-host connections for network services.
TCP-IP network services
Many Internet Protocow-based services are associated wif a particuwar weww-known port number which is standardized by de Internet technicaw governance.
For exampwe, Worwd-Wide-Web servers operate on port 80, and emaiw reway servers usuawwy wisten on port 25.
TCP versus UDP
Different services use different packet transmission techniqwes.
In generaw, packets dat must get drough in de correct order, widout woss, use TCP, whereas reaw time services where water packets are more important dan owder packets use UDP.
For exampwe, fiwe transfer reqwires compwete accuracy and so is normawwy done using TCP, and audio conferencing is freqwentwy done via UDP, where momentary gwitches may not be noticed.
UDP wacks buiwt-in network congestion avoidance and de protocows dat use it must be extremewy carefuwwy designed to prevent network cowwapse.