Role of Sonet Circuits, Packet Handling Operations

Chapter 14 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 14-1illustrates 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 and Cisco ONS 15310-MA Ethernet Card Software Feature and Configuration Guide R8.5

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15310-CL, 15310-MA specifications

Cisco Systems has established itself as a leader in the networking domain, offering a wide array of solutions to meet the needs of modern businesses. Among its impressive product lineup are the Cisco 15310-CL and 15310-MA routers, designed to provide advanced network performance and reliability.

The Cisco 15310-CL is a versatile platform that primarily serves as a carrier-class router aimed at supporting high-speed data and voice services. It is built to handle the demands of large enterprises and service providers, offering a robust design that ensures maximum uptime and performance. One of its standout features is its modular architecture, which enables users to customize their configurations based on specific application needs. This scalability allows for future expansion without the need for a complete hardware overhaul.

Key technologies integrated into the Cisco 15310-CL include high-density Ethernet interfaces and a comprehensive suite of Layer 2 and Layer 3 protocol support. The device is capable of supporting multiple types of connections, including TDM, ATM, and Ethernet. This flexibility makes it an ideal choice for organizations that require seamless migration between various service types. Moreover, with features such as MPLS (Multiprotocol Label Switching) support and advanced Quality of Service (QoS) mechanisms, the router ensures that critical applications receive the necessary bandwidth and low latency required for optimal performance.

In contrast, the Cisco 15310-MA focuses on access solutions, providing a cost-effective entry point for businesses looking to enhance their network capabilities. It is well-suited for smaller offices or branch locations that need reliable connectivity without the expense and complexity associated with larger systems. The device supports a range of access methods and provides essential features like firewall capabilities, VPN support, and comprehensive security measures to protect sensitive data.

Both models benefit from Cisco's commitment to security and manageability, offering features like enhanced encryption protocols and user authentication mechanisms that help safeguard networks against threats. Additionally, they can be managed through Cisco’s intuitive software tools, simplifying configuration and monitoring tasks for IT administrators.

The Cisco 15310-CL and 15310-MA are ideal solutions for businesses seeking to enhance their network infrastructure, ensuring firms can keep pace with evolving technology demands while maintaining a focus on security and performance. Their combination of advanced features, modular capabilities, and robust support makes them valuable assets in the networking landscape.

Cisco Systems 15310-MA, 15310-CL manual Role of Sonet Circuits, Packet Handling Operations, 14-2

Models: 15310-CL 15310-MA

Role of SONET Circuits

Packet Handling Operations

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15310-CL, 15310-MA specifications