Black Box Explains...Media converters that are really switches.
A media converter is a device that converts from one media type to another, for instance, from twisted pair to fiber to take advantage of fiber’s greater range. A traditional... more/see it nowmedia converter is a two-port Layer 1 device that performs a simple conversion of only the physical interface. It’s transparent to data and doesn't “see” or manipulate data in any way.
An Ethernet switch can also convert one media type to another, but it also creates a separate collision domain for each switch port, so that each packet is routed only to the destination device, rather than around to multiple devices on a network segment. Because switches are “smarter” than traditional media converters, they enable additional features such as multiple ports and copper ports that autosense for speed and duplex.
Switches are beginning to replace traditional 2-port media converters, leading to some fuzziness in terminology. Small 4- or 6-port Ethernet switches are very commonly called media converters. In fact, anytime you see a “Layer 2” media converter or a media converter with more than two ports, it’s really a small Ethernet switch.
Black Box Explains...Ethernet hubs vs. Ethernet switches.
Although hubs and switches look very similar and are connected to the network in much the same way, there is a significant difference in the way they function.
What is a... more/see it nowhub?
An Ethernet hub is the basic building block of a twisted-pair (10BASE-T or 100BASE-TX) Ethernet network. Hubs do little more than act as a physical connection. They link PCs and peripherals and enable them to communicate over a network. All data coming into the hub travels to all stations connected to the hub. Because a hub doesnt use management or addressing, it simply divides the 10- or 100-Mbps bandwidth among users. If two stations are transferring high volumes of data between them, the network performance of all stations on that hub will suffer. Hubs are good choices for small- or home-office networks, particularly if bandwidth concerns are minimal.
What is a switch?
An Ethernet switch, on the other hand, provides a central connection in an Ethernet network in which each connected device has its own dedicated link with full bandwidth. Switches divide LAN data into smaller, easier-to-manage segments and send data only to the PCs it needs to reach. They allot a full 10 or 100 Mbps to each user with addressing and management features. As a result, every port on the switch represents a dedicated 10- or 100-Mbps pathway. Because users connected to a switch do not have to share bandwidth, a switch offers relief from the network congestion a shared hub can cause.
What to consider when selecting an Ethernet hub:
• Stackability. Select a stackable hub connected with a special cable so you can start with one hub and add others as you need more ports. The entire stack functions as one device.
• Manageability. Choose an SNMP-manageable hub if you have a large, managed network.
What to consider when selecting an Ethernet switch:
• Manageability. Ethernet switches intended for large managed networks feature built-in management, usually SNMP.
• OSI Layer operation. Most Ethernet switches operate at “Layer 2,” which is for the physical network addresses (MAC addresses). Layer 3 switches use network addresses, and incorporate routing functions to actively calculate the best way to send a packet to its destination. Very advanced Ethernet switches, often known as routing switches, operate on OSI Layer 4 and route network traffic according to the application.
• Modular construction. A modular switch enables you to populate a chassis with modules of different speeds and media types. Because you can easily change modules, the modular switch is an adaptable solution for large, growing networks.
• Stackability. Some Ethernet switches can be connected to form a stack of two or more switches that functions as a single network device. This enables you to start with fewer ports and add them as your network grows. collapse
The difference between unmanaged, managed, and Web-smart switches
With regard to management options, the three primary classes of switches are unmanaged, managed, and Web smart. Which you choose depends largely on the size of your network and how... more/see it nowmuch control you need over that network.
Unmanaged switches are basic plug-and-play switches with no remote configuration, management, or monitoring options, although many can be locally monitored and configured via LED indicators and DIP switches. These inexpensive switches are typically used in small networks or to add temporary workgroups to larger networks.
Managed switches support Simple Network Management Protocol (SNMP) via embedded agents and have a command line interface (CLI) that can be accessed via serial console, Telnet, and Secure Shell. These switches can often be configured and managed as groups. More recent managed switches may also support a Web interface for management through a Web browser.
These high-end switches enable network managers to remotely access a wide range of capabilities including:
Enabling and disabling individual ports or port Auto MDI/MDI-X.
Port bandwidth and duplex control.
IP address management.
MAC address filtering.
Port mirroring to monitor network traffic.
Prioritization of ports for quality of service (QoS).
802.1X network access control.
Link aggregation or trunking.
Managed switches, with their extensive management capabilities, are at home in large enterprise networks where network administrators need to monitor and control a large number of network devices. Managed switches support redundancy protocols for increased network availability.
Web-smart switches—sometimes called smart switches or Web-managed switches—have become a popular option for mid-sized networks that require management. They offer access to switch management features such as port monitoring, link aggregation, and VPN through a simple Web interface via an embedded Web browser. What these switches generally do not have is SNMP management capabilities or a CLI. Web-smart switches must usually be managed individually rather than in groups.
Although the management features found in a Web-smart switch are less extensive than those found in a fully managed switch, these switches are becoming smarter with many now offering many of the features of a fully managed switch. Like managed switches, they also support redundancy protocols for increased network availability.