Enterasys Networks 2H252-25R manual Flow Control, Garp Switch Operation

Overview

Administrators can configure up to four rate limit rules per port; however, each rule must not include conflicting 802.1p priority values. In order to control traffic inbound and outbound on the same port, two rate limit rules must be configured (one inbound and one outbound). Since the rate limiting operation occurs after the processing of the multi-layer classification rules, the two features can be combined to provide application-aware rate limiting.

NOTE: This traffic rate function is not supported on ports connected to SmartTrunk port.

For more information about the application of Traffic Rate Policing, refer to SmartSwitch Series 2E253, 2H252, 2H253, and 2H258 Local Management User’s Guide.

1.1.9Flow Control

Flow control is a method of managing the flow of frames between two devices. It ensures that a transmitting device does not overwhelm a receiving device with data. This is accomplished by the transmitting device pausing its transmission while the receiving device processes the frames already received.

The 2H252-25R supports the following two types of flow control:

•Frame based 802.3x

•Back pressure

Frame based 802.3x flow control is supported on all Ethernet ports operating in the full duplex mode. Flow control can be enabled or disabled on a port-by-port basis.

Back pressure flow control is supported on all Ethernet ports operating in the standard mode of operation. Flow control can be enabled or disabled on a port-by-port basis.

1.1.10 GARP Switch Operation

Some or all ports on the switch may be activated to operate under the Generic Attribute Registration Protocol (GARP) applications, GARP VLAN Registration Protocol (GVRP) and/or GARP Multicast Registration Protocol (GMRP).

GARP is a protocol, or set of rules, that outlines a mechanism for propagating the port state and/or user information throughout a bridged LAN to keep track of users and VLANs on the network fabric. MAC bridges and end users alike can take part in the registration and de-registration of GARP attributes such as VLAN and multicast group membership. For more details on how GVRP and GMRP handle frames under GARP, and how to configure the switch ports to take advantage of this operation, refer to SmartSwitch Series 2E253, 2H252, 2H253 and 2H258 Local Management User’s Guide.

Introduction 1-5