Nokia M1122 User Manual page 18

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Gateway/bridge management interface. This interface is used as a
bridge host interface or gateway interface depending on the
operation mode. In this manual it is called VBRIDGE. On the
M1122 web pages, the interface is called gateway or bridge IP
interface.
M1122 can operate in four different main modes:
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Bridging only
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Routing/tunneling IP only
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Routing/tunneling IP, bridging all but IP
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Routing/tunneling IP and bridging all, including IP
The mode in which M1122 operates depends on the configuration of
the unit's interfaces.
LAN interface
LAN interface can be configured to bridge and route packets. There are
three different operational modes in the LAN interface:
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Bridging only; only bridging is activated in the interface. In this
case the interface bridges all protocols.
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Routing only; only IP address is configured in the interface. In this
case, the interface routes IP packets.
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Bridging and routing; Bridging is activated in the interface and IP
address is configured in the interface. In this case, the interface
routes IP packets and bridges all other packets.
Internal host/gateway interface
There is a special host/gateway logical IP interface within M1122
called VBRIDGE. This interface has a specific purpose in M1122. In
applications where some ATM virtual channel connections are used
for bridging IP traffic and some other ATM virtual channel
connections are used for routing IP traffic, the VBRIDGE interface
must be used instead of LAN IP addresses. Alternatively, this interface
is used in bridge only application when the IP address is required for
remote management purposes.
Data VCC operation
M1122 supports the following encapsulations in each ATM data
virtual channel individually:
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RFC2684 LLC encapsulation for bridged IP (ETH-LLC)
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RFC2684 LLC encapsulation for routed IP (IP-LLC)
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