ZyXEL Communications P-660N-T1A, Руководство пользователя

Страница: 73 / 322

Chapter 6 WAN Setup
P-660N-T1A User’s Guide
73
Multicast Multicast packets are sent to a group of computers on the LAN and are
an alternative to unicast packets (packets sent to one computer) and
broadcast packets (packets sent to every computer).
Internet Group Multicast Protocol (IGMP) is a network-layer protocol
used to establish membership in a multicast group. The ZyXEL Device
supports
IGMP-v1 , IGMP-v2 and IGMP-v3 . Select None to disable
it.
ATM QoS
ATM QoS Type
Select CBR (Continuous Bit Rate) to specify fixed (always-on)
bandwidth for voice or data traffic. Select UBR (Unspecified Bit Rate)
for applications that are non-time sensitive, such as e-mail. Select
rtVBR (real-time Variable Bit Rate) type for applications with bursty
connections that require closely controlled delay and delay variation.
Select
nrtVBR (non real-time Variable Bit Rate) type for connections
that do not require closely controlled delay and delay variation.
Peak Cell Rate Divide the DSL line rate (bps) by 424 (the size of an ATM cell) to find
the Peak Cell Rate (PCR). This is the maximum rate at which the
sender can send cells. Type the PCR here.
Sustain Cell
Rate
The Sustain Cell Rate (SCR) sets the average cell rate (long-term)
that can be transmitted. Type the SCR, which must be less than the
PCR. Note that system default is 0 cells/sec.
Maximum
Burst Size
Maximum Burst Size (MBS) refers to the maximum number of cells
that can be sent at the peak rate. Type the MBS, which is less than
65535.
MTU
MTU
The Maximum Transmission Unit (MTU) defines the size of the largest
packet allowed on an interface or connection. Enter the MTU in this
field.
For ENET ENCAP, the MTU value is 1500.
For PPPoE, the MTU value is 1492.
For PPPoA and RFC 1483, the MTU is 65535.
Back Click this to return to the previous screen without saving.
Apply Click this to save your changes.
Cancel Click this to restore your previously saved settings.
Table 15 Network > WAN > Internet Connection: Advanced Setup (continued)
LABEL DESCRIPTION