Alteon OS Application Guide

Selecting Route Paths in BGP

BGP selects only one path as the best path. It does not rely on metrics attributes to determine the best path. When the same network is learned via more than one BGP peer, BGP uses its policy for selecting the best route to that network. The BGP implementation on the GbE Switch Module uses the following criteria to select a path when the same route is received from multiple peers.

1.Local fixed and static routes are preferred over learned routes.

2.With iBGP peers, routes with higher local preference values are selected.

3.In the case of multiple routes of equal preference, the route with lower AS path weight is selected.

AS path weight = 128 x AS path length (number of autonomous systems transversed).

4.In the case of equal weight and routes learned from peers that reside in the same AS, the lower metric is selected.

NOTE – A route with a metric is preferred over a route without a metric.

5.The lower cost to the next hop of routes is selected.

6.In the case of equal cost, the eBGP route is preferred over iBGP.

7.If all routes are from eBGP, the route with the lower router ID is selected.

When the path is selected, BGP puts the selected path in its routing table and propagates the path to its neighbors.

42C4911, January 2007

Chapter 11: Border Gateway Protocol „ 181

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Nortel Networks 42C4911 manual Selecting Route Paths in BGP
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42C4911 specifications

Nortel Networks 42C4911 is a key hardware component designed to meet the needs of modern telecommunications infrastructure. As part of Nortel's extensive portfolio, the 42C4911 has made a significant impact on network design and operation, particularly in enterprises requiring reliable and efficient communication solutions.

One of the standout features of the 42C4911 is its modularity. This allows for flexible configurations and upgrades, enabling organizations to adapt to changing technology requirements and business demands. The design philosophy behind the 42C4911 emphasizes scalability, allowing users to start with a basic setup and expand it as their networking needs grow. This feature is particularly appealing to medium and large enterprises that anticipate increased data and communication requirements over time.

In terms of technology, the 42C4911 supports various telecommunications standards, making it versatile for multiple applications. It typically integrates with other Nortel equipment and can work with third-party devices, ensuring seamless interoperability across different platforms. This is critical as organizations look to create unified communications systems that can handle voice, data, and video traffic efficiently.

The 42C4911 is known for its robust performance and reliability. It is designed to operate continuously under demanding conditions, which is essential for organizations that rely on constant connectivity for their operations. Its built-in redundancy features help safeguard against potential failures, thus enhancing the overall stability of the network. This reliability is further complemented by Nortel's commitment to high-quality manufacturing standards, ensuring that users receive a durable and efficient product.

Security is another major consideration for any networking device, and the 42C4911 provides advanced security features to protect sensitive data. With increasing cybersecurity threats, organizations prioritize devices that offer strong encryption and access control mechanisms. The 42C4911 addresses these needs while facilitating secure communication channels for users, which is essential in today's increasingly interconnected world.

Overall, the Nortel Networks 42C4911 stands out as a versatile and powerful component in the telecommunications landscape. Its modular design, compatibility with diverse technologies, reliability, and emphasis on security make it an appealing choice for organizations looking to enhance their networks. As companies continue to navigate the complexities of communication, devices like the 42C4911 play a crucial role in ensuring that they remain connected and efficient.
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