Product Architecture - Motorola PTP 300 Series User Manual

Product Architecture

4 Product Architecture
The PTP 300 Series Bridge consists of an identical pair of units deployed one at each end of
the link. The radio link operates on a single frequency channel in each direction using Time
Division Duplex (TDD). One unit is deployed as a master and the other as a slave. The master
unit takes responsibility for controlling the link in both directions. This product features Multiple-
Input Multiple-Output (MIMO) technology as well as Orthogonal Frequency Division Multiplexing
(OFDM) modulation, hence enabling a robust link to be achieved in a non-line-of-sight (NLOS)
environment.
The PTP 300 Series Bridge has been developed to operate within license exempt frequency bands.
The current product range supports:
• ETSI 5.4 GHz band B (5.470-5.725 GHz)
• ETSI 5.8 GHz band C (5.725-5.875 GHz) and the USA 5 GHz ISM band (5.725-5.850 GHz)
The PTP 300 Series Bridge has been designed to coexist with other users of the band in an
optimal fashion using a combination of Transmit Power Control (TPC), Spectrum Management
functionality and Antenna beam shape. In order to maintain link availability, the product employs
adaptive modulation techniques that dynamically switches to a more robust modulation mode in
severe or adverse conditions.
The PTP 300 Series provides wireless Ethernet bridging between two fixed locations. To be more
precise, it forwards Ethernet frames as a two-port transparent heterogeneous encapsulation bridge,
meaning that each bridge forwards frames between two dissimilar interfaces (Ethernet and wireless),
encapsulating Ethernet MAC frames and fragments of de-prioritised Ethernet MAC frames within
PTP MAC frames for transmission at the wireless interface. A link consisting of a pair of back to
back bridges appears to the data network as a standard two-port Ethernet bridge.
The PTP 300 series provides eight traffic classes, classifying Ethernet frames into one of eight
prioritised queues based on inspection of the user priority field (802.1p) in a customer (IEEE802.1Q)
VLAN tag or provider (IEEE802.1ad) VLAN tag. Untagged frames receive a default priority. The
scheduling method is strict priority. The bridge does not implement any VLAN functions for
bridged frames apart from inspection of the priority field, and consequently the bridge forwards
tagged and untagged Ethernet frames regardless of VLAN ID and without modification of any
protocol header fields.
The management function of the PTP 300 Series Bridge is logically equivalent to a separate protocol
stack with virtual point of attachment at the Ethernet interface. This is illustrated in Figure 10.
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