88 WAN advanced configurationNN47928-500NN47928-500PPP ConfigurationOn the Point to Point Protocol (PPP) Configuration page you can configure the IP address of theWAN PPP.To access this page, select Configuration, WAN, DSL, IP Configuration tab.QoS The required Quality of Service (QoS) parameter.Options:Constant Bit Rate (CBR)— reserves a constant amount of bandwidth. Thisservice supports applications such as voice, video, and circuit emulation.CBR service class is designed for ATM virtual circuits (VC) that require astatic amount of bandwidth that is continuously available for the durationof the active connection. An ATM VC configured as CBR can send cells atpeak cell rate (PCR) at any time for any duration. It can also send cells ata rate less than PCR.Variable Bit Rate (VBR)— negotiates the Peak Cell Rate (PCR), theSustainable Cell Rate (SCR), and the Maximum Burst Size (MBS). TypicalVBR sources are compressed voice and video. VBR strives to achieve thebest possible quality of the encoded media. VBR-rt makes better use ofbandwidth if the traffic is bursty, since the ATM interface reservesbandwidth equal to the SCR only.Unspecified Bit Rate (UBR)— efficiently uses the remaining bandwidth,which dynamically changes in time because of VBR service. Typicalapplications are computer communications, such as file transfers ande-mail. UBR service provides no feedback mechanism. If the network iscongested, UBR cells can be lost.The default value is UBR.Encapsulation The encapsulation type.Options:ATM Adaptation Layer 5/Sub Network Access Protocol (AAL5/SNAP)—multiple protocols can be transmitted on the same VC. AAL5 sendsvariable length packets across an Asychronous Transfer Mode (ATM)network. The type 5 adaptation layer is a simplified version of AAL3/4. TheAAL type of the cell defines the format of the payload in the ATM cells.Virtual Channel Multiplexer (VC MUX)— only a single protocol can beused on each VC and the protocol is negotiated during the connectionestablishment phase.MRU The Maximum Receivable Unit (MRU) value. MRU specifies the maximumnumber of bytes received on a link.Keep Alive Time Out The Keep Alive Time Out value, in seconds. If no Echo response packet isreceived within the time-out value, the connection is lost.The default value is 10.PCR/SCR/MBS The traffic parameter of the DSL modem.Peak Cell Rate (PCR) / Sustainable Cell Rate (SCR) and Maximum BurstSize (MBS).The range for PCR/SCR/MBS is 0 to 65535.The default value for PCR and SCR is 4000.The default value for MBS is 10.Variable Value
