PBT operates by adding configured routes to the standard
PBB network.
In addition, 50 ms recovery can also be provided to meet the industry expectation
of service provider networks. In conjunction with Ethernet OAM standards (discussed
later in this chapter), proactive fault management can also be incorporated for these
Ethernet paths. Because PBT transport can be independent of the service carried over
this transport, it can be used to Carrier non-Ethernet services as well.
Given that existing technologies such as MPLS are more established (especially
in the core of Service Provider networks), the need for PBT is being questioned in
some quarters; while proponents claim compelling CAPEX and OPEX savings vis-? -vis
MPLS, the incumbency of MPLS (i.e., already deployed and depreciating) may make it
harder to displace, especially in existing networks. In green field networks, however,
there may be a better opportunity for PBT.
More information on PBT can be obtained from the appropriately noted references.
Reliability
While MEF has defined service-level reliability and its components??™ service resiliency, protection,
and less than 50 ms restoration, several of the underlying transport solutions employed
to deliver Carrier Ethernet, particularly SONET and RPR, have established a high
level of reliability in Service Provider networks.
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