Nortel BSG12aw 1.0, Руководство по настройке

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88 WAN advanced configuration
NN47928-500 NN47928-500
PPP Configuration
On the Point to Point Protocol (PPP) Configuration page you can configure the IP address of the
WAN 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. This
service supports applications such as voice, video, and circuit emulation.
CBR service class is designed for ATM virtual circuits (VC) that require a
static amount of bandwidth that is continuously available for the duration
of the active connection. An ATM VC configured as CBR can send cells at
peak cell rate (PCR) at any time for any duration. It can also send cells at
a rate less than PCR.
Variable Bit Rate (VBR)— negotiates the Peak Cell Rate (PCR), the
Sustainable Cell Rate (SCR), and the Maximum Burst Size (MBS). Typical
VBR sources are compressed voice and video. VBR strives to achieve the
best possible quality of the encoded media.
VBR-rt makes better use of
bandwidth if the traffic is bursty, since the ATM interface reserves
bandwidth equal to the SCR only.
Unspecified Bit Rate (UBR)— efficiently uses the remaining bandwidth,
which dynamically changes in time because of VBR service. Typical
applications are computer communications, such as file transfers and
e-mail. UBR service provides no feedback mechanism. If the network is
congested, 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 sends
variable length packets across an Asychronous Transfer Mode (ATM)
network. The type 5 adaptation layer is a simplified version of AAL3/4. The
AAL type of the cell defines the format of the payload in the ATM cells.
Virtual Channel Multiplexer (VC MUX)— only a single protocol can be
used on each VC and the protocol is negotiated during the connection
establishment phase.
MRU The Maximum Receivable Unit (MRU) value. MRU specifies the maximum
number of bytes received on a link.
Keep Alive Time Out The Keep Alive Time Out value, in seconds. If no Echo response packet is
received 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 Burst
Size (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