Nokia M11 T66220, Руководство пользователя

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Nokia M11 User’s Manual
E
Copyright Nokia Networks Oy C33833001SE_00 2-6
NAPT may restrict the operation of some IP applications. NAPT also
operates as a simple IP firewall because translation is only allowed
when the first packet is transmitted from the LAN. This means that the
NAPT table entry is created only when a packet is sent from the home
network to the Internet. With pinhole capability, the user can add static
entries to the NAPT table allowing the translation always in both
directions. This capability is used to add servers (HTTP, NNTP, and
FTP), which are visible to the public IP network via the VCC, on the
LAN subnet.
Dynamic Host Configuration
M11 can act as a Dynamic Host Configuration Protocol (DHCP)
server for the PCs on the end-user home network. In this mode, M11
can assign up to 253 IP addresses to the PCs on the home network. M11
can also act as a DHCP relay agent and relay the DHCP requests to an
external DHCP server.
ATM and ADSL
M11 supports up to 8 simultaneous VCCs and supports UBR
(Unspecified bit rate) traffic shaping on all VCCs. The maximum
transmit rate on each VCC is the ADSL upstream capacity. If more
than one VCC is transmitting simultaneously, the ADSL upstream
capacity is temporarily shared between these VCCs. When one VCC is
idle, the bandwidth is used by another VCC. M11 also supports limited
CBR on upstream (see Transmit priority selection in this chapter).
The ADSL transmission is based on the DMT line code. M11 provides
a DMT line rate up to 8 Mbit/s downstream and up to 1 Mbit/s
upstream. The DMT transceiver is rate adaptive and capable of
providing faster rates over short distances or slower rates over long
distances. The transceiver adapts itself to the line conditions. M11
supports also ADSL Lite. In the ADSL Lite mode, the maximum line
rates are 1536 kbit/s downstream and 512 kbit/s upstream.
The ATM over ADSL transmission is based on ITU-T G.992.1. ADSL
Lite is based on ITU-T G.992.2.
Rate adaptation is done in steps of 32 kbit/s. The ADSL interface of
M11 functions completely automatically and all configuration related
to the ADSL connection is done at the access multiplexer in the
operator’s premises. The network operator can set the data rates as a
part of the network management functionality provided by Nokia D
DSLAM.