Amer Networks E5Web GUI - Manual (Page 145)

3.3.2. Creating Custom Services
If the list of predefined cOS Core service objects does not meet the requirements for certain
traffic then a new service can be created. Reading this section will explain not only how new
services are created but also provides an understanding of the properties of predefined services.
The Type of service created can be one of the following:
• TCP/UDP Service
A service based on the UDP or TCP protocol or both. This type of service is discussed further
in this section.
• ICMP Service
A service based on the ICMP protocol. This is discussed further in Section 3.3.3, “ICMP Services”.
• IP Protocol Service A service based on a user defined protocol. This is discussed further in
Section 3.3.4, “Custom IP Protocol Services”.
• Service Group
A service group consisting of a number of services. This is discussed further in Section 3.3.5,
“Service Groups”.
TCP and UDP Based Services
Most applications use TCP and/or UDP as transport protocol for transferring data over IP
networks.
Transmission Control Protocol (TCP) is a connection-oriented protocol that includes mechanisms
for reliable point to point transmission of data. TCP is used by many common applications where
error-free transfers are mandatory, such as HTTP, FTP and SMTP.
UDP Orientated Applications
For applications where data delivery speed is of greatest importance, for example with streaming
audio and video, the User Datagram Protocol (UDP) is the preferred protocol. UDP is
connectionless, provides minimal transmission error recovery, and has a much lower overhead
when compared with TCP. Due to the lower overhead, UDP is also used for some non-streaming
services and in those cases the applications themselves must provide any error recovery
mechanisms.
TCP and UDP Service Definition
To define a TCP or UDP based protocol to cOS Core, a TCP/UDP service object is used. Apart from
a unique name describing the service, the object contains information about what protocol (TCP,
UDP or both) and what source and destination ports are applicable for the service.
Specifying Port Numbers
Port numbers are specified with all types of services and it is useful to understand how these can
be entered in user interfaces. They can be specified for both the Source Port and/or the
Destination Port of a service in the following ways:
Chapter 3: Fundamentals
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