Udp - Novell NETWARE 6-DOCUMENTATION Manual

UDP

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NetWare TCP/IP Administration Guide
identify which port the process uses. The port must be in the range of 1,024 to
65,535.
UDP identifies applications through ports. The protocol defines two types of
protocol ports: well-known port assignments and dynamically bound ports.
For well-known port assignments, certain UDP port numbers are reserved for
particular applications. Then the application can direct UDP datagrams to that
port.
UDP enables multiple clients to use the same port number and different IP
addresses. The arriving UDP datagrams are delivered to the client that
matches both the destination port number and address. (A socket consists of
an IP address and the port number.) If there is no matching client or if the
ICMP destination is unreachable then a port unreachable message is sent and
the packet is dropped.
The UDP datagram is encapsulated in an IP datagram that, in turn, is
encapsulated in physical frames.
encapsulated in an IP datagram, which, in turn, is encapsulated in an Ethernet
frame. It also illustrates how the concept of layering, discussed at the
beginning of this section, affects the construction of packets sent across the
network.
Figure 3 on page 17 shows a UDP datagram