3Com SuperStack II PathBuilder S330 Reference Manual

Also see for S330: Reference guide

Contents

Configuring Virtual Circuits 129Configuring VirtualCircuitsAfter you have configured the modules and ports on the PathBuilder S330/S310switch, you can start setting up virtual circuits. A virtual circuit is a bi-directionalpath between data ports of connecting ATM units. You should have a circuit plandeveloped in advance.The PathBuilder S330/S310 switch supports both VPCs (virtual path connections)and VCCs (virtual channel connections). A virtual path is an aggregate collectionof virtual channels for the purpose of assigning the channels to a single physicallayer. A virtual channel is a connection between data ports.n You define a VPC at the connecting units by assigning it a Virtual Path Identifier(VPI) for each direction of transmission.n You define a VCC at the connecting units by assigning it a Virtual PathIdentifier (VPI) and a Virtual Channel Identifier (VCI) for each direction oftransmission. You can connect one or more virtual circuits to a data port byassigning each a different VPI and VCI. The VPI and VCI numbers are normallyassigned as a pair: VPI/VCI.When you add a virtual circuit, you make a connection from the selected port tofor traffic to flow through the PathBuilder S330/S310 switch and across the ATMWAN service. Typically, the VPI and VCI numbers for one side of the circuit areassigned by the network service provider or local IS administrator—depending onwhether your network is a public or private ATM network.The port VPI/VCI ATM circuit designators must match the application beingsupported. For example, if an OC3/STM-1 multi-mode fiber module is installed inthe Side B slot of the PathBuilder S330/S310 switch and is connected to a LANATM switch device, then the Rx VPI/VCI for the ATM LAN interface must match theTx VPI/VCI for the OC3/STM-1 UNI module and vice versa. This ensures the firststep in making the connection into the PathBuilder S330 switch.Supported Classes ofVirtual CircuitsThe PathBuilder S330/S310 switch supports four classes of virtual circuits;PVC — Standard VP/VCC permanent virtual circuits connecting various type ofdata ports. For details about setting up PVC virtual circuits, see “Adding PVCVirtual Circuits” later in this chapter.RS-366 Template — Video-associated virtual circuit templates. When the circuitdefined by an RS-366 template is activated, it supports dialed video conferencingover an ATM network. For details setting up RS-366 virtual circuit templates, see“Defining RS-366 (Video) Virtual Circuit Templates” later in this section.VCM VCC — Voice Compression module VCC virtual circuits. VCM VCC circuitscarry individual voice, fax, modem, or data connections. For details about settingup VCM VCC circuits, see “Adding Voice Compression Module VCC Circuits” laterin this chapter.VCM Subchannel — Voice Compression module subchannel circuits. VCMsubchannel circuits carry multiple voice samples from a single DS0. For detailsabout setting up subchannel circuits, see “Adding VCM Subchannel Circuits” laterin this chapter.