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This chapter contains introductory information about the SuperStack® Switch management software and how it can be used in your network. It covers the following topics:
Your Switch contains software that allows you to change and monitor the way it works. This management software is not required to get the Switch working, but if you do use it, you may improve the efficiency of the Switch and therefore improve the overall performance of your network.
Table 3 describes the software features that are supported by units in the Switch 1100/3300 and 610/630 family.
Units in the Switch 1100/3300 family can be interconnected so that they form a stack, that is, a group of devices that are managed as a single device.
Stackability is not supported by the Switch 610/630 units.
You can interconnect these Switch units together in two ways:
For information about stacking Switch units, refer to Chapter 2 of the relevant Switch User Guide.
Units in the Switch 3300/630 family support Store and Forward packet forwarding mode. In this mode, received packets are buffered entirely before they are forwarded, which ensures that only good packets are forwarded to their destination.
Units in the Switch 1100/610 family support three forwarding modes in addition to Store and Forward:
For information about setting the forwarding mode for units in the Switch 1100/610 family, see "Configuring the Advanced Stack Settings".
All the ports on your Switch can be set to one of two duplex modes:
To communicate effectively, both ends of a link must use the same duplex mode. If the link uses an auto-negotiating connection, this is done automatically. If the link uses a connection that is not auto-negotiating, both ends must be set to half duplex or full duplex manually.
For more information about setting the duplex mode of a port, see "Configuring a Port".
All the ports on your Switch support flow control, which is a congestion control mechanism. Congestion is caused by one or more devices sending traffic to an already overloaded port on the Switch. Flow control prevents packet loss and inhibits the devices from generating more packets until the period of congestion ends.
Flow control is implemented in two ways:
For information about enabling flow control on a port, see "Configuring a Port".
Your Switch supports IEEE 802.1p traffic prioritization, which allows data that has been assigned a high priority to be forwarded through the Switch without being obstructed by other data. The system works by using the multiple traffic queues that are present in the hardware of the Switch - high priority traffic is forwarded on a different queue from other traffic, and it is always given preference over the other traffic.
Traffic prioritization can be useful for critical applications that require a high Class of Service (CoS) from the network. This could include:
If you use IEEE 802.1p traffic prioritization, we recommend that all relevant ports on your Switch are placed in one or more Virtual LANs (VLANs) using 802.1Q tagging. For a brief explanation of VLANs, see "Virtual LANs". For a detailed explanation of VLANs and 802.1Q tagging, see "Virtual LANs (VLANs)".
Your Switch supports PACE (Priority Access Control Enabled) which is a 3Com proprietary feature that allows multimedia traffic to move across a network effectively.
PACE provides two main features:
For information about enabling PACE on an individual port, see "Configuring a Port". For information about enabling PACE on a whole Switch or stack, see "Configuring the Advanced Stack Settings".
Each port on your Switch can use a security feature that guards against unauthorized users connecting devices to your network. When security is enabled on a port, it enters Single Address Learning Mode. In this mode, the Switch:
Once the first address is learned:
For more information about enabling security on a port, see "Configuring a Port".
The resilient link feature of the Switch enables you to protect critical links and prevent network downtime should those links fail. Setting up resilience ensures that if a main communication link fails, a standby duplicate link immediately and automatically takes over the task of the main link. Each main and standby link pair is referred to as a resilient link pair.
Resilient links are a simple method of creating redundancy that provides you with an instant reaction to link failure. Resilient links are quick to set up, you have full control over their configuration, and the port at the other end of the resilient link does not have to support any resilience feature.
For more information about resilient links, see "Setting Up Resilient Links" .
Your Switch supports port trunks - connections that allow devices to communicate using up to four links in parallel. Port trunks provide two benefits:
For more information about port trunks, see "Port Trunks" .
Your Switch supports Broadcast Storm Control, a system that automatically creates an alarm for each port to monitor the level of broadcast traffic on that port. If the broadcast traffic level rises to 2976 frames per second, the broadcast traffic on the port is blocked until the broadcast traffic level drops to 1488 frames per second. This system prevents the overwhelming broadcast traffic that can result from network equipment which is faulty or configured incorrectly.
For more information about enabling Broadcast Storm Control, see "Configuring the Advanced Stack Settings".
Your Switch provides supports for up to 16 Virtual LANs (VLANs). A VLAN is a flexible group of devices that can be located anywhere in a network, but they communicate as if they are on the same physical segment. With VLANs, you can segment your network without being restricted by physical connections - a drawback of traditional network design. As an example, with VLANs you can segment your network according to:
For more information, see "Virtual LANs (VLANs)".
Your Switch supports FastIP, a system that reduces the load on routing devices when VLANs are implemented on your network.
Devices within different VLANs can only communicate using a routing device; if there is a large amount of inter-VLAN traffic, the router can become overloaded and network performance can be affected. FastIP allows your endstations and Switch units to find secure short-cuts for inter-VLAN traffic that bypass the routing device altogether.
For more information about FastIP, see "FastIP".
Your Switch supports two multicast filtering systems:
These systems allow the Switch to forward multicast traffic to the endstations that are interested rather than broadcasting the traffic to the whole network.
For more information, see "Multicast Filtering".
Your Switch supports the Spanning Tree Protocol (STP), a bridge-based system that makes your network more resilient to link failure and also provides a protection from loops - one of the major causes of broadcast storms.
STP allows you to implement parallel paths for network traffic and uses a loop-detection process to:
For information about STP, see "Spanning Tree Protocol". For information about enabling STP, see "Configuring the Advanced Stack Settings".
Your Switch supports RMON (Remote Monitoring), a system that allows you to monitor LANs remotely. The Switch contains RMON probe software that continually collects statistics about the LAN segments connected to the Switch. If you have a management workstation with an RMON management application, the Switch can transfer these statistics to your workstation on request or when a pre-defined threshold is crossed.
For more information, see "RMON".
Your Switch supports roving analysis, a system that allows you to attach a network analyzer to one port and use it to monitor the traffic of other ports on the Switch. The system works by enabling you to define an analysis port (the port that is connected to the analyzer), and a monitor port (the port that is to be monitored). Once the pair are defined, and you enable the system, the Switch takes all the traffic going in and out of the monitor port and copies it to the analysis port.
Roving analysis is used when you need the functions of a network analyzer, but do not want to change the physical characteristics of the monitored segment by attaching an analyzer to that segment.
For information about setting up roving analysis ports, see "Setting Up Roving Analysis Ports".
Your Switch can be managed using three methods:
For information about setting up your Switch for management, see "Setting Up for Management".
Table 4 shows the default settings of units in the Switch 1100/3300 and 610/630 family. If you initialize one of these Switch units, it is returned to these defaults.