GarrettCom 6K8 manual Frame Buffering and Flow Control

Page 20

Magnum 6K8-Series Industrial Field Switch

Installation and User Guide 03/06)

The Magnum 6K8-Series switching hardware supports the IEEE 802.1p standard and fulfills its role in support of QOS, giving packet processing priority to priority tagged packets according to the 802.1p standard. In addition to hardware support for QOS, the MNS software (Rel3) supports two priority queues that can be shared across the eight levels of defined packet priorities for application-specific priority control by the user through software configuration settings.

2.2.8Frame Buffering and Flow Control

Magnum 6K8-Series’s are store-and-forward switches. Each frame (or packet)

is loaded into the Switch’s memory and inspected before forwarding can occur. This technique ensures that all forwarded frames are of a valid length and have the correct CRC, i.e., are good packets. This eliminates the propagation of bad packets, enabling all of the available bandwidth to be used for valid information.

While other switching technologies (such as "cut-through" or "express") impose minimal frame latency, they will also permit bad frames to propagate out to the Ethernet segments connected. The "cut-through" technique permits collision fragment frames (which are a result of late collisions) to be forwarded which add to the network traffic. Since there is no way to filter frames with a bad CRC (the entire frame must be present in order for CRC to be calculated), the result of indiscriminate cut- through forwarding is greater traffic congestion, especially at peak activity. Since collisions and bad packets are more likely when traffic is heavy, the result of store-and- forward operation is that more bandwidth is available for good packets when the traffic load is greatest.

When the Magnum 6K8-Series Switch detects that its free buffer queue space is low, the Switch sends industry standard (full-duplex only) PAUSE packets out to the devices sending packets to cause “flow control”. This tells the sending devices to temporarily stop sending traffic, which allows a traffic catch-up to occur without dropping packets. Then, normal packet buffering and processing resumes. This flow- control sequence occurs in a fraction of a second and is transparent to an observer.

Another feature implemented in Magnum 6K8-Series Switches is a collision-based flow- control mechanism (when operating at half-duplex only). When the Switch detects that its free buffer queue space is low, the Switch prevents more frames from entering by forcing a collision signal on all receiving half-duplex ports in order to stop incoming traffic. The flow control option is user configurable (enable/disable) through the setport command of MSN-6K software as per the requirement of a network.

www . GarrettCom . com

15

Image 20
Contents Industrial Field Switch Trademarks Contacting GarrettCom, Inc Canadian EmissionIntroduction Table of ContentsInstallation Troubleshooting Overview Repeater Port Modules RPMs, 6 types for Ethernet mediaTechnical Specifications PerformanceNetwork Standards and Compliance, hardware Maximum 10 Mbps Ethernet Segment LengthsFiber Single-mode connector types Alarm Relay ContactsManagement Console connector Power Supply InternalDC Power Supply Options Per-port MDI or Mdix on RJ-45Mountings Agency Approvals Magnum 6K8Magnum 6K8 Port Modules Configuration OptionsOrdering Information GBIC1000Mb Transceiver options for Mangum 6K8-Series Introduction Inspecting the Package and Product Product Description Magnum 6K8-Series 6K8 1a Magnum 6K8-Series, Industrial Field Switch Www . GarrettCom . com Eight-port SFF fiber modules 6K8-MTRJ, 6K8-MLC, 100Mb Fiber Eight-Port Copper Module, 6K8-RJ45 Six-Port 4 + 2Combo Modules, 4@ 10/100 RJ-45 and 2@100MbFiber4@RJ-45 + 2@ 100Mb ST or SCFour-Port 10 Mb and 100Mb mm Fiber ST Modules Gigabit 1000Mbps port modules Packet Prioritization, 802.1p QOSFrame Buffering and Flow Control Managed Network Software MNS-6K for Magnum 6K8-Series „ Managed switching for high performance Ethernet LANs „ Large selection of built-in fiber options at 10/100/1000MbApplications Magnum 6K25 Control Center Scada Locating Magnum 6K8-Series Switches Mounting InstructionsConnecting Ethernet Media Connecting Fiber Optic ST-type, twist-lockIeee Standard Media Type Max. Distance Port Module Fiber CopperMedia Ieee Standard Connecting Fiber Optic SC-type, Snap-InConnecting Single-Mode Fiber Optic Twisted Pair CAT 5E 1000BASE-T RJ-45 Www . GarrettCom . com Quantity Description Installing DIN-RAIL variable brackets on Magnum 6K8Din-Rail kit Installation procedures Www . GarrettCom . com Mounting Dimensions for 6K8 with metal brackets Powering the Magnum 6K8-Series Industrial Field Switch 6K8-Series Port Module 6KPMV Installation Preparation for Installing and Removing 6KPMVs from 6K8’s StopDaughter board Power LED, Pin J5 Power Supply, Pin Dssv Installing 6KPM Cards in the Magnum 6K8-Series 2a a Magnum 6K8 unit with main boardmotherboard onlyFemale latch connector 2b Granddaughter Board shown separately6KPMV Cards into a Magnum 6K8-Series Securely latching up Www . GarrettCom . com Connecting a Management Console Terminal to Magnum 6K8 Retaining screws shown by arrows Remove 6KPM CardRemoving a 6KPM Card Enlarged view of Magnum 6K8-Series Console Port areaDB-9 Console port connector 1 RS-232 DB-9 Console Com port Serial port pin assignmentsAddress Learning Switching FunctionalityFiltering and Forwarding Dual LEDs Status on TOP and Front of the 6K8-Series unit Auto-CrossMDIX and Auto-negotiation, for RJ-45 portsOn with port activity for 10 Mbps and 100Mbps operation OFF for half duplexWww . GarrettCom . com Flow-control, Ieee 802.3x Standard 6KP4V ’cvrIntroduction Magnum 6K8 Industrial Field Switch Port Modules 6KPMV Module DescriptionDual-mode ST-type connectors 6KP4-F10ST, 4@10Mb multi-mode FX-ST twist lock Module Connector Www . GarrettCom . com 5 6KP8-MTRJ, 8 @100Mb multi-mode FX , Mtrj Small-Form-factor Port@ 100Mbps Multi-Mode Fiber portMtrj type ports. The small size Mtrj connectors provides an Magnum 6KP8-45MTModule is a combo module with Copper and fiber Small Form Factor9 6KP8-RJ45 Twisted Pair, 10/100Mb 8-Port 45-2MT eight port Module is a GBIC-SXSC Gigabit fiber1000Mb, multi-mode SC Connector 11a GBIC-LXSC Gigabit fiber 1000Mb, multi-mode SC Connector @ 1000Mb Fiber SC + 2@ 100Mb SCBefore Calling for Assistance No Problem Found When Calling for AssistanceReturn Material Authorization RMA Procedure Appendix B Internal DC Power Supply Options Shipping and Packaging InformationB2.0 -48VDC, 24VDC and 125VDC POWER, Theory of Operation B3.0B4.0 6K8-SERIES, -48V, 24, 125 or 5VDC Installation B4.1 UL Requirements for DC-powered units B5.0 OperationC3.0 DUAL-SOURCE OPTION, Theory of Operation C5.0 Installation C5.1 UL RequirementsC6.0 Ordering Information Optional Example Magnum 6K8 -24VDC
Related manuals
Manual 76 pages 56.37 Kb