Cisco Systems 15327 RPR-IEEE Features on the ML-Series Card, Advantages of RPR-IEEE, Role of SONET/SDH Circuits

26-2
Ethernet Card Software Feature and Configuration Guide, R7.2
January 2009
Chapter 26 Configuring IEEE 802.17b Resilient Packet Ring
RPR-IEEE Features on the ML-Series Card
Note Throughout this book, Cisco proprietary RPR is referred to as Cisco proprietary RPR, and
IEEE 802.17b-based RPR is referred to as RPR-IEEE. Th is chapter covers RPR-IEEE. Chapter 17,
“Configuring Cisco Proprietary Resilient Packet Ring” covers Cisco Proprietary RPR.
RPR-IEEE Features on the ML-Series Card
See the “ML-Series Feature List” section on page 1-2 for a list of the ML-Series card’s supported and
non-supported features based on the expected IEEE 802.17b.
Advantages of RPR-IEEE
In Software Release 7.2 and later, the ML-Series card supports RPR-IEEE in addition to Cisco
proprietary RPR. Some of the advantages of RPR-IEEE include:
• Steering. Ring protection is accomplished through steering instead of wrapping. St eering is a more
efficient way of routing around a failure.
• Dual-transit queues. Dual-transit queues offer more control in handling transit traffic.
• Best-effort traffic classifications. “Best Effort” and “EIR” traffic classifications improve
distribution of traffic across a best-effort service class.
• Interoperability. Conformance to the expected IEEE 802.17b standard increases interoperability
with third-party vendors.
• Built-in service provider support. RPR-IEEE provides built-in operations, administration, and
maintenance (OAM) support for service provider environments.
• Fairness. Fairness allows all the stations on the ring to fairly share the RPR-IEEE’s best-effort
bandwidth.
Role of SONET/SDH Circuits
The ML-Series cards in an RPR-IEEE must connect directly or indirectly through point-t o-point
synchronous transport signal/synchronous transport module (STS/STM) circuits. The point-to- point
STS/STM circuits are configured on the ONS node through Cisco Transport Controller (CTC) or
Transaction Language One (TL1) and are transported over the ONS node’s SONET/SDH topology on
either protected or unprotected circuits.
On circuits unprotected by the SONET/SDH mechanism, RPR-IEEE provides resiliency without using
the capacity of the redundant protection path that a SONET/SDH protected circuit would require. This
frees this capacity for additional traffic. RPR-IEEE also utilizes the bandwidth of the entire ring and does
not block segments like STP or RSTP.