BGP: Concepts and Terminology

Update attributes

As mentioned above, each BGP update message contains a set of attributes. These attributes describe some of the properties of the routes, and can be used in making decisions about which routes to accept and which to reject. Some of the attributes are:

Origin

How a prefix came to be routed by BGP at the origin Autonomous System (AS). Prefixes are learned from various sources such as directly connected interfaces, manually configured static routes, or dynamic internal or external routing protocols, and then put into BGP.

AS-path

The list of Autonomous Systems (ASs) through which the announcement for the prefix has passed. As prefixes pass between Autonomous Systems each one adds its Autonomous System Number (ASN).

Next-hop

The address of the next node that the router should send packets destined for the specified prefixes to, in order to get the packets closer to the destination.

Multi-Exit-Discriminator (MED)

A metric expressing the optimal path to reach a particular prefix in or behind a particular AS.

Local-preference

A metric used in IBGP so each host knows which path inside the AS it should use to reach the advertised prefix. EBGP peers do not send this value, and ignore it on receipt.

Atomic-aggregate

A non-transitive attribute that allows BGP peers to inform each other about decisions they have made regarding overlapping routes. Non-transitive means that if the attribute is received by a device that does not recognise the attribute, it is dropped and not passed on to the next router.

Aggregator

Can be attached to an aggregated prefix to specify the AS and router that performed the aggregation.

Community

Indicates where a prefix is relevant to—for example, if it is relevant to the whole Internet, or just within an AS.

Use Route Maps and Other Filters to Filter and Alter BGP and OSPF Routes Page 5

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Allied Telesis X8100, x908 Update attributes, Origin, AS-path, Next-hop, Multi-Exit-Discriminator MED, Local-preference
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X8100, x908 specifications

The Allied Telesis x908 and the SwitchBlade x900 series of network switches are cutting-edge solutions designed to address the demands of modern networking environments. These switches are known for their high performance, reliability, and robust feature sets, making them ideal for enterprise and service provider networks.

The Allied Telesis x908 series consists of modular and chassis-based systems that can accommodate a variety of network configurations. One of the main features of the x908 series is its ability to offer high scalability with support for a large number of ports. This makes it suitable for data centers and large enterprise networks where space and bandwidth optimization are critical.

In addition to scalability, the x908 series supports advanced Layer 2 and Layer 3 switching capabilities. This allows for efficient traffic management and routing, ensuring that data is delivered swiftly and reliably. The x908 also incorporates intelligent features such as Quality of Service (QoS), which prioritizes critical network traffic, ensuring that time-sensitive data—like voice and video—maintains its quality during transmission.

The SwitchBlade x900 series takes this functionality further with its innovative modular architecture. This allows organizations to configure their networks to meet specific needs by choosing from a variety of interface cards and service modules. The SwitchBlade x900 also supports advanced security features such as Access Control Lists (ACLs) and VLAN segmentation, which provide enhanced protection against unauthorized access and network threats.

Another hallmark of the x908 and SwitchBlade series is their support for high-speed Ethernet technologies, including 10G and 40G Ethernet. This enables organizations to keep pace with the increasing bandwidth demands of applications and services, particularly in cloud computing and data-intensive workloads.

Both the x908 and the SwitchBlade x900 series are designed with energy efficiency in mind, featuring power-saving technologies that reduce overall operational costs. Coupled with Allied Telesis' management tools, which provide detailed analytics and monitoring, network administrators can optimize performance and energy consumption simultaneously.

In summary, the Allied Telesis x908 and SwitchBlade x900 series offer a comprehensive suite of features, high performance, scalability, and advanced networking technologies. They represent a strategic investment for organizations looking to build resilient, efficient, and future-proof network infrastructures.
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