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BGP

BGP in the Data Center

If you think that BGP is a Server Provider (SP) only protocol and is not your business in the data center, then better think again because BGP is coming to your territory. Traditionally for Enterprises and DCs; BGP commonly took part at the Internet edge in multi-homing scenarios (the internet from multiple ISPs) where BGP provided such networks with better control of upstream and downstream internet traffic as well as some other extra redundancy features as compared to basic default/static routing. With the current Cloud evolution and demands, BGP can generally be used in many different solutions in the DC domain. …

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What is 6PE?

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6PE is one of the efficient solutions for interconnecting IPv6 islands over an IPv4-only MPLS cloud without needing to drastically change the core network design by having all your Core routers dual-stacked 6PE does not use manual standard tunnels, it provides an alternative where all tunnels are established dynamically eliminating the need to configure and maintain tunnels. The approach requires that the edge routers connected to IPv6 islands be Dual Stack Multiprotocol-BGP-speaking routers. while the core routers can only run IPv4 MPLS Configuring 6PE is has a lot of similarities with configuring  IPv4 VPNs as both use MP-BGP to distribute non-IPv4 reachability …

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BGP Weight Attribute

BGP weight attribute is a Cisco proprietary path attribute that is local to the router and is used to influence local path selection on a certain router. BGP weight is the first in the list: BGP weight is the first tie breaker for best path selection on a Cisco router, the attribute is not propagated to other routers in the BGP updates and only found on Cisco routers. The path with the highest weight is selected as the best toward a destination. BGP weight values: The weight can be a number from 0 to 65,535. Paths that the router originates …

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BGP Attributes List

BGP Attributes are pieces of information that a BGP router attaches to describe different prefixes included in it’s BGP update messages. There is a variable sequence of BGP attributes in every update message except for those that carries only withdrawn routes. Each attribute is a TLV that consists of attribute type, attribute length and attribute value. Each attribute type consists of two octets, one for flag and the other is the type as described briefly in the following section. BGP attributes have different distinctive types that defines how routes are going to use and propagate a certain attribute to it’s …

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BGP Attributes: Local Preference Attribute

The local preference attribute is a well-know discretionary attribute. This means local preference must be recognized by all BGP implementations, but will not exist in all BGP update messages; specifically it will not exist in E-BGP update messages. BGP local preference attribute is one of the most used attributes in BGP real world to influence traffic. Local preference attribute is a four octet field of information that is used to inform internal peers about the autonomous system internal preference for an advertised route.

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BGP Attributes: Atomic Aggregate Atribute

Atomic aggregate is a Well-known Discretionary attribute; it must be recognized by all BGP implementations and does not have to exist in all BGP updates. The purpose of the attribute is to alert BGP speakers along the path that some information have been lost due to the route aggregation process and that the aggregate path might not be the best path to the destination. When some routes are aggregated by an aggregator, the aggregator does attache its Router-ID to the aggregated route into the AGGREGATOR_ID attribute and it sets the ATOMIC_AGGREGATE attribute or not; based on whether the AS_PATH information …

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