10.6.3. Access Points with HG 3575 
An HG 3575 is used as the central board for each access point. Access
points are only connected to the central system via IP. A maximum of
83 access points can be configured in a system.
As regards addresses, a distinction must be made between “networked“
and “direct link“ access points.
“Networked“ access points are in a different network segment to
the central system and can therefore only be reached via a router.
“Direct Link“ access points are connected in the same network
segment as the central system.
The OpenScape 4000 system is used for configuring addresses and the
port settings. The access point is stored locally. The parameters must
be set locally for initial startup.
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PHY
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10/100 Base T - autosensing or can be permanently
set
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MAC address
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Permanently programmed on the board, ->sticker
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IP addresses
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See below
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IEEE 802.1 p/q VLAN tagging
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Configurable; priority bits are always set when
active. See Table
3 “TOS values” in document “Gateways HG 3500 and HG
3575”.
The VLAN ID can be set. Configuration in the OpenScape
4000 system.
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TOS/DiffServ
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The six highest bits in the TOS byte can be
set. See Table
3 “TOS values” in document “Gateways HG 3500 and HG
3575”. Configuration in the OpenScape 4000 system.
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Protocols/ports
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See Chapter
20, “IP Ports” in the document “Gateways HG 3500 and
HG 3575”.
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Routing
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Routing table configured in the OpenScape 4000
system with a default route and up to eight additional routes. Routing
can be individually set for the access point.
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Number of connections
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Up to 30/60/120 RTP and RTCP connections to
any HG 3500 or access points.
Connection setup controlled completely
from OpenScape 4000.
H.323 Fast Connect for direct media connections
outside the IPDA gateway network, no gatekeeper necessary.
Up to
two TCP/IP connections to the central processor.
When using AP
Emergency features and a TCP/IP connection to the survivability unit.
See
Section 3.1,
“Load Calculation for Access Points” for connection
bandwidths.
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IP addresses for “networked“ access points:
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IP address of the access point
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For signaling, payload, SNMP, FTP, Telnet.
Address must be routed in the network.
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IP address for signaling survivability
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This address remains invisible in the LAN as
it is only used for the PPP connection between the survivability router
and modem connection of the access point.
This address is assigned
indirectly by configuring the network address for the virtual survivability
network (PPP via ISDN). Only a “private“ address such as 192.168.x.0
should be used here.
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IP address for “direct link“ access points:
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IP address of the access point
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For payload, SNMP, FTP, Telnet, however not
for signaling. See Figure 13
“Difference between “networked“ and “direct link“ access point”
. Address must be in the same network segment as the central
processor.
Address must be routed in the network.
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IP address for signaling
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The signaling connection between the central
processor and the access point must pass via a router. See Figure 13
“Difference between “networked“ and “direct link“ access point”
.
If the LAN connection fails, the current TCP connection
is rerouted for signaling survivability. This can only be performed by
changing the router whereas the destination address remains the same.
An
internal router which routes between the access point IP address and
the internal address of the signaling instance is therefore used for
“direct link“ access points.
The IP address for signaling must
be in a separate “private“ network segment. It is visible in the
LAN (using a sniffer) as the destination address of the signaling packet.
However,
as signaling packets are routed exclusively from the central processor
to the access point IP address via the host route, no router needs to/must
route this address in the LAN.
Only a “private“ address such
as 192.168.x.0 should be used here.
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IP address for signaling survivability
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This address remains invisible in the LAN as
it is only used for the PPP connection between the survivability router
and modem connection of the access point.
This address is assigned
indirectly by configuring the network address for the virtual survivability
network (PPP via ISDN). Only a “private“ address such as 192.168.x.0
should be used here.
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