Exam Description
The 642-661 Configuring BGP on Cisco Routers (BGP) exam is a qualifying exam for the Cisco Certified Internetwork Professional certification. The 642-661 BGP exam tests material covered under the Configuring BGP on Cisco Routers (BGP) v 3.1 course. The BGP exam assesses a candidate’s understanding of the theory of BGP, ability to configure BGP on Cisco IOS routers, and skills with troubleshooting on BGP. As a routing protocol, BGP is one of the underlying foundations of the Internet and new-world technologies.
Exam Topics
The following information provides general guidelines for the content likely to be included on the BGP exam. However, other related topics may also appear on any specific delivery of the exam.
I. BGP Overview
Introduction to BGP
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Given a network scenario, identify appropriate BGP usage and its limitations
BGP Session Establishment
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Given a typical BGP network scenario, describe the concept of BGP neighbors and the neighbor session establishment procedures
BGP Route Processing
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Given a diagram of an operational BGP network, describe interdomain route processing, route propagation and BGP path selection
Basic BGP Configuration
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Given a network consisting of multiple domains, successfully configure BGP
Monitoring and Troubleshooting BGP
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Given a configured BGP network, verify proper operation and perform the steps necessary to correct basic BGP configuration errors
II. Route Selection Using Policy Controls
Multi-Homed BGP Networks
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Given a customer scenario where connections to multiple ISPs must be supported, describe the need for influencing BGP route selection
AS-Path Filters
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Given a customer scenario where connections to multiple ISPs must be supported, successfully configure BGP to influence route selection using AS path filters
Prefix-List Filters
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Given a customer scenario where connections to multiple ISPs must be supported, successfully configure BGP to influence route selection using prefix-list filters
Outbound Route Filtering
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Given an operational BGP network, use outbound route filtering to minimize the impact of BGP routing updates on router resources
Route-Maps as BGP Filters
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Given a typical BGP network, correctly configure BGP to influence route selection using route maps
Implementing Changes in BGP Policy
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Given a typical BGP network, configure the route-refresh feature to minimize the impact of expediting BGP policy updates
III. Route Selection Using Attributes
BGP Path Attributes
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List BGP path attributes and functionality of each attribute Influencing BGP Route Selection with Weights
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Given a customer scenario where multiple connections must be supported, successfully configure BGP to influence route selection using the weight attribute
BGP Local Preference
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Given a customer scenario where multiple connections must be supported, successfully configure BGP to influence route selection using the local preference attribute
BGP Multi-Exit-Discriminator (MED)
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Given a customer scenario where multiple connections must be supported, successfully configure BGP to influence route selection using the Multi-Exit-Discriminator (MED) attribute
BGP Communities
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Given a customer scenario where multiple connections must be supported, successfully configure BGP to influence route selection using BGP community attributes
IV. Customer-to-Provider Connectivity with BGP
Customer Connectivity Requirements
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Describe the requirements to connect customer networks to the Internet in a service provider environment
Static Routing Toward the Customer
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Given a service provider network, implement customer connectivity using static routing
BGP Customer Multi-Homed to a Single Service Provider
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Given a customer scenario where multiple connections to a single ISP must be supported, implement customer connectivity with BGP
BGP Customer Multi-Homed to Multiple Service Providers
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Given a customer scenario where connections to multiple ISPs must be supported, implement customer connectivity with BGP
V. BGP Transit Autonomous System
Transit Autonomous System Functions
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Describe the function of a transit autonomous system and the need for IBGP IBGP and EBGP Interaction in a Transit AS
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Given a transit autonomous system, describe the interaction between EBGP and IBGP in relation to relevant BGP attributes
Packet Forwarding in Transit Autonomous Systems
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Describe the function of an IGP in forwarding packets through an autonomous system
Configuring a Transit Autonomous System
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Given a BGP network scenario, successfully configure an autonomous system to act as a transit backbone
Monitoring and Troubleshooting IBGP in Transit AS
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Given a configured BGP transit network, verify proper operation and perform the steps necessary to correct basic IBGP configuration errors
VI. BGP Route Reflectors
Introduction to Route Reflectors
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Describe the function and operation of route reflectors in a BGP environment
Network Design with Route Reflectors
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Based upon established route reflector design rules, describe the concept of hierarchial route reflectors and their requirements
Configuring and Monitoring Route Reflectors
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Given an existing IBGP network, configure and verify proper operation of route reflectors to modify IBGGP split-horizon rules
VII. Advanced BGP Configuration
Limiting the Number of Prefixes Received from a BGP Neighbor
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Given a typical BGP network, successfully configure BGP to limit the number of prefixes received from a neighbor
AS-Path Prepending
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Given a typical service provider network with connections to multiple autonomous systems, use AS-Path prepending to influence the return path selected by the neighboring autonomous systems
BGP Peer Group
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Given a typical BGP network, use BGP peer groups to share common configuration parameters between multiple BGP peers
BGP Route Flap Dampening
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Given a properly configured BGP network, use route flap dampening to minimize the impact of unstable routes
VIII. Scaling IGP and BGP in Service Provider Networks
Common Routing Issues in Service Provider Networks
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Describe common routing concerns of service provider networks
Optical Networking Designs
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Describe the scalability issues of using OSPF and IS-IS as interior gateway protocols in a service provider network and list solutions for each
Scaling BGP in Service Provider Networks
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Describe common scalability issues when using BGP in a service provider network and list solutions for each