Chapter 6 Broadband
VMG1312-B Series User’s Guide
94
6.3 The 3G Backup Screen
Use this screen t o configure your 3G set t ings. Click Ne t w or k Set t ing > Br oadband > 3 G
Backup.
Encapsulation
Mode
Select t he m ethod of m ultiplexing used by your I SP from the drop-down list box . Choices
are:
• LLC/ SNAP- BRI DGI N G: I n LCC encapsulat ion, bridged PDUs are encapsulat ed by
ident ifying the t ype of t he bridged m edia in t he SNAP header. This is available only when
you select I PoE or PPPoE in t he Select DSL Link Type field.
• VC/ MUX: I n VC m ult iplexing, each prot ocol is car ried on a single ATM virt ual circuit
(VC) . To t ransport m ultiple protocols, the Device needs separate VCs. Ther e is a binding
between a VC and t he t ype of the network prot ocol carried on the VC. This reduces
payload overhead since t here is no need t o carry prot ocol inform ation in each Protocol
Data Unit (PDU) payload.
• LLC/ EN CAPSULATI ON : More t han one protocol can be carried over t he sam e VC. This
is available only w hen you select PPPoA in the En capsu lation field.
• LLC/ SNAP- ROUTI NG: I n LCC encapsulation, an I EEE 802.2 Logical Link Cont rol ( LLC)
header is prefixed to each rout ed PDU t o ident ify t he PDUs. The LCC header can be
followed by an I EEE 802.1a SubNet work At tachment Point (SNAP) header. This is
available only when you select I PoA in t he Enca psula t ion field.
Service
Category
Select UBR W it hout PCR or UBR W it h PCR for applicat ions that are non- t im e sensit ive,
such as e- m ail.
Select CBR ( Continuous Bit Rat e) to specify fixed (always- on) bandwidth for voice or data
traffic.
Select Non Realtim e VBR ( non real-tim e Variable Bit Rat e) for connect ions t hat do not
require closely controlled delay and delay variat ion.
Select Realtim e VBR (real- t im e Variable Bit Rat e) for applications with bursty connect ions
that require closely controlled delay and delay variation.
Peak Cell Rat e Divide the DSL line rat e ( bps) by 424 ( t he size of an ATM cell) t o find t he Peak Cell Rat e
( PCR). This is the m axim um rate at which the sender can send cells. Ty pe the PCR here.This
field is not available when you select UBR W ithout PCR.
Su st ain ab le Cell
Rat e
The Sustainable Cell Rat e ( SCR) set s the average cell rat e ( long- t erm ) t hat can be
transm itted. Type t he SCR, w hich m ust be less t han t he PCR. Note that system default is 0
cells/ sec.
This field is available only when you select N on Realt im e VBR or Re a ltim e VBR.
Maxim um Bur st
Size
Maxim um Burst Size ( MBS) refers t o the m axim um num ber of cells t hat can be sent at the
peak rate. Type the MBS, which is less t han 65535.
This field is available only when you select N on Realt im e VBR or Re a ltim e VBR.
QoS
Rat e Lim it Ent er t he rate lim it for the connect ion. This is t he m axim um transmission rat e allowed for
traffic on this connect ion.
Apply Click Apply t o save your changes.
Cancel Click Cance l to exit this screen without saving.
Table 10 Bridge Mode (ADSL over ATM) (cont inued)
LABEL DESCRIPTION
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