ZyXEL Communications P-660HNU-Fx User Manual

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Chapter 5 Broadband
ADSL Series User’s Guide
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5.3  Technical Reference
The following section contains additional technical information about the ZyXEL Device features 
described in this chapter.
Encapsulation
Be sure to use the encapsulation method required by your ISP. The ZyXEL Device can work in 
bridge mode or routing mode. When the ZyXEL Device is in routing mode, it supports the following 
methods.
IP over Ethernet 
IP over Ethernet (IPoE) is an alternative to PPPoE. IP packets are being delivered across an 
Ethernet network, without using PPP encapsulation. They are routed between the Ethernet interface 
and the WAN interface and then formatted so that they can be understood in a bridged 
environment. For instance, it encapsulates routed Ethernet frames into bridged Ethernet cells. 
PPP over Ethernet
Point-to-Point Protocol over Ethernet (PPPoE) provides access control and billing functionality in a 
manner similar to dial-up services using PPP. PPPoE is an IETF standard (RFC 2516) specifying how 
a personal computer (PC) interacts with a broadband modem (DSL, cable, wireless, etc.) 
connection. 
Encapsulation Mode
The encapsulation method of multiplexing used by your is LLC/SNAP-BRIDGING. In 
LCC encapsulation, bridged PDUs are encapsulated by identifying the type of the 
bridged media in the SNAP header. 
Service Category
Select UBR Without PCR for applications that are non-time sensitive, such as e-mail. 
Select CBR (Constant Bit Rate) to specify fixed (always-on) bandwidth for voice or 
data traffic. 
Select Non Realtime VBR (non real-time Variable Bit Rate) for connections that do 
not require closely controlled delay and delay variation.
Select Realtime VBR (real-time Variable Bit Rate) for applications with bursty 
connections that 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.
Sustainable 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. 
Apply
Click Apply to save your changes.
Back
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Table 14   
Broadband Add/Edit: Bridge (ADSL) (continued)
Label
DESCRIPTION