Dell PowerConnect 2708 User Manual

Also see for 2724 - PowerConnect Switch: Appendix Datasheet Getting started guide

Contents

Dell PowerConnect 2708 User Manual Manual pdf 9 page image

9FeaturesGeneral FeaturesHead of Line Blocking PreventionHead of Line (HOL) blocking results in traffic delays and frame loss caused by traffic competingfor the same egress port resources. HOL blocking queues packets, and the packets at the head ofthe queue are forwarded before packets at the end of the queue. By default, the device is configuredso that the HOL blocking prevention mechanism is active at all times, except when QoS (Qualityof Service), Flow Control or Back Pressure is active on a port where the HOL blocking preventionmechanism is disabled on the whole system.Management Modes• Unmanaged Mode — Operates independent of user-configuration. The switch does not havean IP address, nor is there a web management interface and thus cannot be managed. This isthe system default. From Unmanaged Mode, when the Managed Mode button is pressed, theswitch enters Managed Mode with the default IP address of 192.168.2.1.• Managed Mode — Provides switch management through a web interface, and maintains thedevice configuration through power cycles. From Managed Mode, when the Managed Modebutton is pressed, the switch enters Unmanaged Mode.• Secure Mode (PowerConnect 2748 only) — Secure Mode works by the user configuringthe switch in Managed Mode and then enabling Secure Mode. Once enabled, it preventsusers from making any further configuration changes to the switch. This is done by removingthe IP address to the switch so that it becomes inaccessible. In Secure Mode the switchretains configuration through power cycles just like Managed Mode. To use Secure Mode, theuser puts the switch in Managed Mode, configures the switch as desired, and then switches toSecure Mode via the web interface. To exit Secure Mode, the user presses the Managed Modebutton. From Secure Mode when the Managed Mode button is pressed, the switch entersManaged Mode default configuration with the default IP address of 192.168.2.1.Back Pressure SupportOn half-duplex links, the receiving port prevents buffer overflows by occupying the link so that it isunavailable for additional incoming traffic. The user may enable or disable this feature on aper-port basis. The default status on all ports is set to OFF. However, this applies to links operatingat Half Duplex only.