User's Guide Part 1

Chapter 1: Product description Ethernet bridging
Lowest Second Data Modulation Mode
The PTP 700 ODU can be configured to discard Ethernet frames in the Second Data Service
when the modulation mode is lower than the configured Lowest Second Data Modulation
Mode.
This feature is likely to be useful in networks that have alternate routes, for example in a ring or
mesh topology where EAPS or RSTP is used to resolve loops. In this application, Lowest
Second Data Modulation Mode should be set to ensure that an active link will provide at least
the minimum necessary capacity for high-priority constant bit rate traffic such as voice over IP
or TDM pseudo wire. An active link will be blocked when the capacity falls below the minimum
required, triggering a routing change in associated Ethernet switches to bring alternate links
into use.
Lowest Second Data Modulation Mode should normally be set to BPSK 0.63 Single in simply
connected tree networks or other topologies that do not have alternative routes.
Further reading
For information about…
Refer to…
Factors to be considered when planning
PTP 700 customer data networks
Data network planning on page 3-35
How to configure the Ethernet Second Data
Service
LAN Configuration page on page 6-34
How to configure Ethernet quality of service QoS Configuration page on page 6-44
How to monitor Ethernet performance System statistics on page 7-47
Out-of-Band Management Service
Transparent Ethernet service
The PTP 700 Series provides an optional Ethernet service for out-of-band network management
between one of the Ethernet ports at a local ODU and one of the Ethernet ports at an
associated remote ODU. The Ethernet service is based on conventional layer two transparent
bridging. The PTP 700 maintains complete separation between Ethernet traffic in the customer
Data Service and the Management Service.
The service is transparent to untagged frames, standard VLAN frames, priority-tagged frames,
provider bridged frames, Q-in-Q frames and provider backbone bridged frames. In each case,
the service preserves MAC addresses, VLAN ID, Ethernet priority and Ethernet payload in the
forwarded frame. The maximum frame size for bridged frames in the management network is
2000 bytes.
There is no requirement for the management network to be connected to the same Ethernet
port at both ends of a wireless link. For example, it is possible to connect the Main PSU port to
the management network at one end of the link and to connect the Aux port to the
management network at the other end of the link.
Page 1-26