ZyXEL Communications P-2812HNU-51c, Руководство пользователя

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Chapter 5 WAN Setup
P-2812HNU-51c User’s Guide
95
The following table describes the fields in this screen.
Table 16 Layer 2 Interface Configuration
LABEL DESCRIPTION
ATM PVC
Configuration VPI (Virtual Path Identifier) and VCI (Virtual Channel Identifier) define
a virtual circuit. This section is available only when you configure an
ATM layer-2 interface.
VPI The valid range for the VPI is 0 to 255. Enter the VPI assigned to you.
VCI The valid range for the VCI is 32 to 65535 (0 to 31 is reserved for local
management of ATM traffic). Enter the VCI assigned to you.
Select DSL Link
Type Select EoA (Ethernet over ATM) to have an Ethenet header in the
packet, so that you can have multiple services/connections over one
PVC. You can set each connection to have its own MAC address or all
connections share one MAC address but use different VLAN IDs for
different services. EoA supports ENET ENCAP (IPoE), PPPoE and
RFC1483/2684 bridging encapsulation methods.
Select PPPoA (PPP over ATM) to allow just one PPPoA connection over
a PVC.
Select IPoA (IP over ATM) to allow just one RFC 1483 routing
connection over a PVC.
Encapsulation
Mode Select the method of multiplexing used by your ISP from the drop-
down list. Choices are:
• VC/MUX: In VC multiplexing, each protocol is carried on a single
ATM virtual circuit (VC). To transport multiple protocols, the P-
2812HNU-51c needs separate VCs. There is a binding between a
VC and the type of the network protocol carried on the VC. This
reduces payload overhead since there is no need to carry protocol
information in each Protocol Data Unit (PDU) payload.
• LLC/ENCAPSULATION: More than one protocol can be carried
over the same VC. This is available only when you select PPPoA in
the Select DSL Link Type field.
• LLC/SNAP-ROUTING: In LCC encapsulation, an IEEE 802.2
Logical Link Control (LLC) header is prefixed to each routed PDU to
identify the PDUs. The LCC header can be followed by an IEEE
802.1a SubNetwork Attachment Point (SNAP) header. This is
available only when you select IPoA in the Select DSL Link Type
field.
• LLC/SNAP-BRIDGING: In LCC encapsulation, bridged PDUs are
encapsulated by identifying the type of the bridged media in the
SNAP header. This is available only when you select EoA in the
Select DSL Link Type field.
Service Category Select UBR Without PCR or UBR With PCR for applications that are
non-time sensitive, such as e-mail.
Select CBR (Continuous Bit Rate) to specify fixed (always-on)
bandwidth for voice or data traffic.
Select Realtime VBR (real-time Variable Bit Rate) for applications
with bursty connections that require closely controlled delay and delay
variation.
Select Non Realtime VBR (non real-time Variable Bit Rate) for
connections that do not require closely controlled delay and delay
variation.