Information Technology Reference
In-Depth Information
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Project completion in 30 days
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Diverse administration
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Accommodate an aggressive acquisition strategy
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Accommodate a new Internet connectivity design
Potential Solutions
The key issue is the network's instability. This instability is actually a result of uncontrolled
growth of the network without a clear architectural goal. The number of prefixes in the
network and lack of summarization are a recipe for disaster. The real fix for this network is
to clean up the addressing and EIGRP design.
Stability is not the only issue. The time frame does not permit enough time to clean up
the EIGRP and addressing. A single EIGRP process across the network does not allow the
administrative separation that is needed to accommodate the aggressive acquisition strategy.
Requirements Analysis
The requirements need to be compared against the available BGP architectures. The first
three requirements would be satisfied equally well by any of the three architectures. The
last three are the determining factors in choosing a design.
The internal BGP core architecture does not allow for a clean delineation of administrative
control. The aggressive acquisition strategy can also result in rapid iBGP mesh expansion.
The internal/external BGP core architecture provides the best solution to the design
requirements. The external BGP core architecture requires the team of individuals manag-
ing the intersite connectivity to have control over the core routers in each region. The IT
staff at each regional site must also have control over these same routers to manage regional
routing, which does not provide good administrative control.
In this scenario, the internal/external BGP core architecture is chosen because of better
reconvergence characteristics and the use of an IGP in the core to provide optimized routing
based on link speed. There is also less administrative overhead when troubleshooting con-
nectivity between two locations that are not directly connected. This architecture also provides
the greatest amount of flexibility for future policy requirements.
Solution Description
The new architecture with the BGP core in place is shown in Figure 5-21. This new topol-
ogy involves the creation of six BGP autonomous systems (65100 through 65105). The net-
work core is one AS, each major center is its own AS, the remote site aggregation is another
AS, and the Internet connectivity is the final AS.
