Overview
1-2
Introduction
The 2E253-49R is a 48-port high-speed network switching device that supports traditional
switching (bridging) and Cabletron Systems SecureFast Switching Virtual Network technology.
The optional HSIMs provide one or more additional ports for high speed uplinks to networking
technologies such as Fast Ethernet, Gigabit Ethernet, Fiber Distributed Data Interface (FDDI),
Wide Area Networks (WANs), and Asynchronous Transfer Mode (ATM). The HSIMs also provide
additional Fast Ethernet ports in varying media types. The optional VHSIMs provide very high
speed uplinks to networking technologies such as Gigabit Ethernet and ATM.
The 2E253-49R ports can be configured to control frame traffic in several ways, including
prioritizing traffic flow according to protocol type. The 2E253-49R can also be configured to
establish Virtual Local Area Networks (VLANs) and control the flow of frames associated with
each VLAN according to priority and Ether type. Detailed information about VLANs is provided
in the Cabletron Systems SmartSwitch Series 2E253, 2H252, 2H253, and 2H258 Local
Management User’s Guide.
The 2E253-49R may be used as a tabletop unit or can be installed in a standard 19-inch rack using
the supplied rack mounting hardware.
The 2E253-49R has two universal ac power supplies with automatic voltage sensing that allows
operation using 100–125 or 200–240 Vac, 50/60 Hz. The power supplies load share 50% (+/-5%)
of the power required by the device. If one power supply fails, the remaining power supply
assumes the entire load of the device without interruption to network traffic. Each power supply
module supports its own ac input connection, which allows the user to connect each power supply
to a different ac power circuit.
1.1.1
Connectivity
The 2E253-49R connects to Ethernet networks or workstations through four 50-pin RJ21
connectors. Each connector is wired for 12 ports. These ports support Unshielded Twisted Pair
(UTP) cables with an impedance between 85 and 111 ohms at lengths up to 100 meters. The ports
are IEEE 802.3 10BASE-T compliant.
The device also has a slot for an optional HSIM or VHSIM to provide additional connectivity to
various networking technologies.
1.1.2
Full Duplex Switched Ethernet
Each switched Ethernet port supports full Ethernet communications and can be configured to
operate in Full Duplex Switched Ethernet (FDSE) mode. FDSE allows each port to provide a
dedicated 20 Mbps bandwidth for file server or high-end workstation connections.
