Information Technology Reference
In-Depth Information
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9
Service Provider Architecture
This chapter provides an overview of how an ISP network is architected from a BGP per-
spective. You can view this entire chapter as a case study, with the initial section detailing
the physical infrastructure, design guidelines, and base configuration templates.
A BGP communities-based policy architecture is defined. This BGP community design
provides efficient route filtering based on prefix origination, flexible customer-defined
routing policy, and QoS-based service level definition.
The chapter concludes with a look at BGP security in an ISP network. That section covers
TCP MD5 signatures, inbound route filtering, graded BGP dampening, public peering
scenarios, and a dynamic traffic black-holing system for combating distributed denial-of-
service (DDoS) attacks.
A final edge router configuration example is provided at the end of the chapter. It includes
all the features that are discussed. The configurations for the core and aggregation routers
remain unchanged from the initial example.
General ISP Network Architecture
This section describes the standard network architecture found in the vast majority of
medium and large ISP networks. The basic network design is broken into several major
components:
•
Interior Gateway Protocol (IGP) layout
•
Network layout
•
Network addressing methodology
•
Customer connectivity
•
Transit and peering connections
These components form the basic architecture for an ISP network.
