Lantronix C 7/01, Руководство пользователя

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Introduction Network Protocols
1-3
Network Protocols
Device Servers use IP protocols for network communications. The supported protocols are
ARP, UDP, TCP, ICMP, Telnet, TFTP, DHCP, HTTP, SNMP, and BOOTP. For
connections to the serial port, TCP, UDP, or Telnet protocols are used. Firmware updates
can be performed using TFTP.
The Internet Protocol (IP) defines addressing, routing, and data block handling over the
network. The Transmission Control Protocol (TCP) assures that no data is lost or
duplicated, and that everything sent to the connection arrives correctly at the target.
For typical datagram applications in which devices interact with other devices without
maintaining a point-to-point connection, User Datagram Protocol (UDP) is used.
Packing Algorithms
Two firmware selectable packing algorithms define how and when packets are sent to the
network. The standard algorithm is optimized for applications in which the Device Server
is used in a local environment, allowing for very small delays for single characters while
keeping the packet count low. The alternate packing algorithm minimizes the packet count
on the network, and is especially useful in applications in a routed Wide Area Network
(WAN). Adjusting parameters in this mode can economize the network data stream.
Ethernet (MAC) Address
The Ethernet address is also referred to as the hardware address or the MAC address. The
first three bytes of the Ethernet Address are fixed (e.g., 00-20-4A), identifying the unit as
a Lantronix product. The fourth, fifth, and sixth bytes are unique numbers assigned to each
Device Server.
Figure 1-1: Sample Ethernet Address
Internet Protocol (IP) Address
Every device connected to an IP network must have a unique IP address. This address is
used to reference the specific Device Server.
Port Numbers
Every TCP connection and every UDP datagram is defined by a destination IP address and
a port number. For example, a Telnet application commonly uses port number 23. A port
number is similar to an extension on a PBX system.
00-20-4A-14-01-18 or 00:20:4A:14:01:18