Chapter 8 Management Network Connectivity

TCP/IP and OSI Networking

Figure 8-16

Level 1 and Level 2 OSI Routing

 

 

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When you provision an ONS 15310-MA SDH for a network with NEs that use both the TCP/IP and OSI protocol stacks, you will provision it as one of the following:

End System—The ONS 15310-MA SDH performs OSI ES functions and relies upon an IS for communication with nodes that reside within its OSI area.

Intermediate System Level 1—The ONS 15310-MA SDH performs OSI IS functions. It communicates with IS and ES nodes that reside within its OSI area. It depends upon an IS L1/L2 node to communicate with IS and ES nodes that reside outside its OSI area.

8.6.4.1End System-to-Intermediate System Protocol

ES-IS is an OSI protocol that defines how ESs (hosts) and ISs (routers) learn about each other. ES-IS configuration information is transmitted at regular intervals through the ES and IS hello messages. The hello messages contain the subnetwork and network layer addresses of the systems that generate them.

The ES-IS configuration protocol communicates both OSI network layer addresses and OSI subnetwork addresses. OSI network layer addresses identify either the NSAP, which is the interface between OSI Layer 3 and Layer 4, or the NET, which is the network layer entity in an OSI IS. OSI SNPAs are the points at which an ES or IS is physically attached to a subnetwork. The SNPA address uniquely identifies each system attached to the subnetwork. In an Ethernet network, for example, the SNPA is the 48-bit MAC address. Part of the configuration information transmitted by ES-IS is the NSAP-to-SNPA or NET-to-SNPA mapping.

8.6.4.2 Intermediate System-to-Intermediate System Protocol

IS-IS is an OSI link-state hierarchical routing protocol that floods the network with link-state information to build a complete, consistent picture of a network topology. IS-IS distinguishes between Level 1 and Level 2 ISs. Level 1 ISs communicate with other Level 1 ISs in the same area. Level 2 ISs route between Level 1 areas and form an intradomain routing backbone. Level 1 ISs need to know only how to get to the nearest Level 2 IS. The backbone routing protocol can change without impacting the intra-area routing protocol.

OSI routing begins when the ESs discover the nearest IS by listening to ISH packets. When an ES wants to send a packet to another ES, it sends the packet to one of the ISs on its directly attached network. The router then looks up the destination address and forwards the packet along the best route. If the destination ES is on the same subnetwork, the local IS knows this from listening to ESHs and forwards

Cisco ONS 15310-MA SDH Reference Manual, Release 9.1 and Release 9.2

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Cisco Systems 15310-MA End System-to-Intermediate System Protocol, Intermediate System-to-Intermediate System Protocol

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.