Distribution Layer Switches - Cisco RJ-45-to-AUX Brochure

Key Features and Benefits
The Catalyst 3900 has the following features:
Twenty shielded Token Ring ports for 150−ohm shielded twisted pair (STP) or 100−ohm unshielded
twisted pair (UTP) connectivity
FlexSlot accommodating two expansion modules or one double−wide module for future expansion
Nine−pin EIA/TIA−232 interface for local console or modem connectivity
Automatic 4−, 16−, and 32Mbps speed adaptation
TokenChannel switch interconnect
MAC address and protocol (DSAP/SNAP) filters
IEEE and IBM Spanning−Tree Protocol
The Catalyst 3920 provides the following features:
Twenty−four shielded Token Ring ports for 150−ohm STP or 100−ohm UTP connectivity
Nine−pin EIA/TIA−232 interface for local console or modem connectivity
Automatic 4−, 16− and 32Mbps speed adaptation
TokenChannel switch interconnect
MAC address and protocol (DSAP/SNAP) filters
Spanning−Tree Protocol
When you need to upgrade the Catalyst 3900 or 3920 IOS, you can do so by using the same serial port that is
used for configuration. You can upgrade code by using Trivial File Transfer Protocol (TFTP) from a TFTP
server or uploaded through the workstation using HyperTerminal. Table E.7 shows key features of the
Catalyst 3900 series.
Table E.7: The key features of the Cisco Catalyst 3900 series.
Feature
Ports
Stack slot
Expansion slots
Backplane
Processor
DRAM
Stackable

Distribution Layer Switches

The Distribution layer is the demarcation point between the Access and Core layers. This level terminates the
traffic that originates in the Access layer connections and summarizes the traffic before passing it along to the
Core layer. It can best be described as the layer that provides policy−based connectivity.
The main focus of the Distribution layer is to define the boundaries for the network and to provide packet
manipulation of the network traffic. It provides isolation from topology changes, manages the size of the
routing table, and aggregates network traffic.
In addition, interdomain traffic is redistributed at the Distribution layer, and static and dynamic route
redistribution occurs at this point. This layer is also commonly used as the point at which remote sites connect
to the network. Let's take a look at the different switches typically found at this layer.
In this section we'll be looking at the following switches:
3900
20/24/28
1
1 FlexSlot
520Mbps
Intel 960SA
Up to 8MB
Yes
364
3920
24
1
None
520Mbps
Intel 960SA
Up to 8MB
Yes