Cambium Networks PTP 820 Series User Manual page 565

Chapter 9: TDM Services and Interfaces
Configuring a Tunnel Group
This section includes:
•
TDM Pseudowire Path Protection Overview
•
Viewing Tunnel Groups
•
Configuring the Revertive Timer
•
Adding a Tunnel Group
•
Editing a Tunnel Group
•
Deleting a Tunnel Group
TDM Pseudowire Path Protection Overview
TDM pseudowire path protection enables you to define two separate network paths for a single TDM pseudowire
service. Each path has the same destination address, but traffic flows to the destination via different paths.
TDM pseudowire path protection requires the use of SOAM (CFM) at both end-points. The TDM interface sends
two data streams to the COY. Only the data stream for the active path contains actual traffic. Both data streams
contain continuity messages (CCMs). This enables the TDM interface to monitor the status of both paths without
doubling the amount of data being sent over the network. The TDM interface determines when a switchover is
necessary based on the monitored network status.
In order to achieve path protection, different provisioning should be made for the Ethernet service corresponding
to each of the two data streams. In order to do this, it is recommended to map the corresponding Ethernet
services to MSTP instance number 63, which is meant for Traffic Engineering (ports are always forwarding) and to
map the two different transport VLANs over two different paths.
TDM path protection uses CFM to monitor the network paths. Because SOAM (CFM) is configured on the TDM
interface level, the TDM interface can determine the status of the entire network path, up to and including the
interface itself.
To configure a TDM service with path protection, you must perform the following steps:
•
Configure a Maintenance Domain – see
•
Configure Maintenance Associations (MAs) – see
•
Configure PSN Tunnels and Assign to them MAs – see
•
Configure a TDM Tunnel Group – see below
TDM pseudowire path protection is implemented by combining two TDM tunnels into a single tunnel group. One
of the tunnels in the group is designated as the primary tunnel. The other tunnel is designated as the secondary
tunnel. CCM messages are sent from the TDM interface to the CPU via both tunnels. However, only the primary
tunnel sends actual traffic. The CPU monitors both paths using the CCM messages, and determines when to
perform a switchover from the primary tunnel to the secondary tunnel.
Viewing Tunnel Groups
To view all the tunnel groups configured for the unit:
1 Select TDM > TDM PseudoWire > Advanced > PSN Tunnels > Tunnel Groups. The PseudoWire Tunnel
Groups page opens.
Figure 331 Pseudowire Tunnel Groups Page
Configuring Pseudowire Maintenance Domains (MDs)
Configuring Pseudowire Maintenance Associations (MAs)
Configuring a Tunnel
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Configuring Advanced Pseudowire Parameters