Chapter 15 Configuring Resilient Packet Ring on the ML-Series Card

Understanding RPR

SONET, when used in this role. Although the IEEE 802.17 draft was used as reference for the Cisco ML-Series RPR implementation, the current ML-Series card RPR protocol does not comply with all clauses of IEEE 802.17.

Role of SONET Circuits

The ML-Series cards in an SPR must connect directly or indirectly through point-to-point STS circuits. The point-to-point STS circuits are configured on the ONS node and are transported over the ONS node’s SONET topology with either protected or unprotected circuits.

On circuits unprotected by the SONET mechanism, RPR provides resiliency without using the capacity of the redundant protection path that a SONET protected circuit would require. This frees this capacity for additional traffic. RPR also utilizes the bandwidth of the entire ring and does not block segments like STP or RSTP.

Packet Handling Operations

When an ML-Series card is configured with RPR and is made part of an SPR, the ML-Series card assumes a ring topology. If a packet is not destined for network devices bridged through the Ethernet ports of a specific ML-Series card, the ML-Series card simply continues to forward this transit traffic along the SONET circuit, relying on the circular path of the ring architecture to guarantee that the packet will eventually arrive at the destination. This eliminates the need to queue and process the packet flowing through the nondestination ML-Series card. From a Layer 2 or Layer 3 perspective, the entire RPR looks like one shared network segment.

An ML-Series card configured with RPR has three basic packet-handling operations: bridge, pass-through, and strip. Figure 15-1illustrates these operations. Bridging connects and passes packets between the Ethernet ports on the ML-Series and the packet-over-SONET (POS) ports used for the SONET circuit circling the ring. Pass-through lets the packets continue through the ML-Series card and along the ring, and stripping takes the packet off the ring and discards it.

The RPR protocol, using the transmitted packet's header information, allows the interfaces to quickly determine the operation that needs to be applied to the packet. It also uses both the source and destination addresses of a packet to choose a ring direction. Flow-based load sharing helps ensure that all packets populated with equal source- and destination-address pairs will be sent in the same direction, and arrive at their destination in the correct order. Ring direction also enables the use of spatial reuse to increase overall ring aggregate bandwidth. Unicast packets are destination stripped. Destination stripping provides the ability to have simultaneous flows of traffic between different parts of an RPR. Traffic can be concurrently transmitted bidirectionally between adjacent nodes. It can also can span multiple nodes, effectively reusing the same ring bandwidth. Multicast packets are source stripped.

Cisco ONS 15310-CL, ONS 15310-MA, and ONS 15310-MA SDH Ethernet Card Software Feature and Configuration Guide, R9.1 and R9.2

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ONS 15310-CL, ONS 15310-MA, Cisco ONS 15310-MA specifications

Cisco Systems has long been a leader in networking and telecommunications technology, and among its impressive lineup of products, the Cisco ONS 15310 series stands out as an essential solution for optical networking. This series includes models such as the ONS 15310-MA, ONS 15310-CL, and ONS 15310-CA, each designed to meet the diverse needs of service providers and enterprises seeking to enhance their optical transport networks.

The Cisco ONS 15310-MA is an advanced multi-service platform designed for metropolitan area networks. It facilitates the seamless transport of data, voice, and video over optical networks. One of its main features is its ability to support a variety of interfaces, including Ethernet, SONET/SDH, and Wavelength Division Multiplexing (WDM), allowing users to integrate multiple services into a single platform. Additionally, the ONS 15310-MA supports advanced traffic management and Quality of Service (QoS) features to prioritize critical applications and ensure consistent performance.

The ONS 15310-CL variant is tailored for more specific applications, providing enhanced capabilities aimed at delivering carrier-grade services. It features a robust architecture that accommodates high-capacity traffic without compromising reliability. This model emphasizes low power consumption and a compact design, making it suitable for deployment in space-constrained environments. The ONS 15310-CL also supports a wide range of optical interfaces, making it highly flexible for various network configurations.

In terms of technologies, the Cisco ONS 15310 series leverages Optical Transport Network (OTN) capabilities, providing high efficiency and greater bandwidth utilization. OTN technology enables efficient error correction and adds resilience to the network through its built-in protection mechanisms. Furthermore, the series supports seamless integration with existing IP/MPLS networks, creating a cohesive infrastructure as organizations evolve their networking requirements.

One of the defining characteristics of the ONS 15310 series is its focus on scalability. Network operators can start with a modest deployment and gradually expand capacity as demand grows. This adaptability is complemented by Cisco's comprehensive management and monitoring tools, providing operators with real-time insights into network performance and facilitating proactive management.

In conclusion, the Cisco ONS 15310-MA and ONS 15310-CL models represent sophisticated solutions for modern optical networks. With their versatile features, advanced technologies, and robust design, they empower service providers and enterprises to build resilient, high-capacity networks that meet the demands of today’s data-driven world.
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