Questions and Answers
What is the primary dynamic routing protocol used by service providers to share routes with each other?
In the TCP/IP protocol suite, what layer is Border Gateway Protocol classified as?
What is the destination well-known port used by Border Gateway Protocol?
How do BGP peers communicate with each other at layer 3?
Signup and view all the answers
What is required for two routers to become BGP peers?
Signup and view all the answers
What is assigned to a service provider in BGP?
Signup and view all the answers
What is the function of BGP in the context of service providers?
Signup and view all the answers
What is the term used to refer to the other router that we're talking to when using BGP?
Signup and view all the answers
What is the main reason R2's static route for 10.1.0.0 is not advertised to R3?
Signup and view all the answers
Why is the 10.1.0.0 network learned via EIGRP after the static route is removed?
Signup and view all the answers
What happens to the EIGRP-learned route for 10.1.0.0 when BGP is configured and the network is advertised?
Signup and view all the answers
What is the purpose of the neighbor
command in the BGP configuration on R1?
Signup and view all the answers
What is the significance of the remote-as
command in the BGP configuration on R1?
Signup and view all the answers
Why is the BGP route for 10.1.0.0 not immediately learned on R3 after the BGP configuration is applied?
Signup and view all the answers
What is the show ip bgp summary
command used for in this scenario?
Signup and view all the answers
What is the main reason the BGP-learned route for 10.1.0.0 replaces the EIGRP-learned route in the routing table of R3?
Signup and view all the answers
Which of these methods is NOT mentioned as a way a router can learn a network route?
Signup and view all the answers
What does the statement "The router or the device with the network interface card that's configured with an IP address effectively lives on that network" refer to?
Signup and view all the answers
What is the main difference between eBGP and iBGP?
Signup and view all the answers
What is the administrative distance for routes learned via external BGP?
Signup and view all the answers
Which routing protocol has the highest administrative distance, thus is considered the least trustworthy?
Signup and view all the answers
When R3 learns about the 10.1.0.0 network from multiple sources, which source will it prioritize?
Signup and view all the answers
What represents a peering relationship where two routers belong to different autonomous systems?
Signup and view all the answers
In the context of BGP routing, what does 'neighborship' refer to?
Signup and view all the answers
If Router 3 learns the same network route from multiple sources, which route from the sources it learns would it trust the least?
Signup and view all the answers
Which statement best describes the relationship between Router 4, Router 5, and Router 6 in the context of internal BGP?
Signup and view all the answers
Which routing protocol has the lowest administrative distance and therefore is the most preferred among the ones discussed?
Signup and view all the answers
Which routing protocol is most commonly used internally by organizations that have specific needs or are Cisco shops?
Signup and view all the answers
What determines which route successfully enters the routing table when a router learns the same exact network from multiple sources?
Signup and view all the answers
Which of the following is not an example of an interior gateway routing protocol mentioned?
Signup and view all the answers
What is the primary type of routing protocol used by service providers for sharing routes?
Signup and view all the answers
Which of the following statements about link-state routing protocols is true?
Signup and view all the answers
Why are static routes considered a challenge in dynamic networks?
Signup and view all the answers
Study Notes
Border Gateway Protocol (BGP)
- BGP is a dynamic routing protocol used to share routes between service providers on the internet.
- It can handle tens and hundreds of thousands of routes.
- BGP is an application layer service that uses TCP (Transmission Control Protocol) and has a destination well-known port of 179.
Characteristics of BGP
- BGP does not use a multicast address; instead, it uses a unicast address of the peer (other router).
- BGP routers are assigned an autonomous system number (ASN).
- BGP peers can be in different autonomous systems, and they can still share routes with each other.
BGP Peering Relationships
- External BGP (eBGP) peering relationships occur between two BGP routers in different autonomous systems.
- Internal BGP (iBGP) peering relationships occur between two BGP routers in the same autonomous system.
- eBGP has a better administrative distance than iBGP, making it more believable and reliable.
Administrative Distance
- The administrative distance (AD) of a routing protocol determines how believable it is to a router.
- The lower the AD, the more believable the route is.
- The AD of BGP-learned routes is 20, which is better than most interior gateway routing protocols.
BGP and Route Selection
- If a router learns the same network from multiple sources (e.g., RIP, OSPF, EIGRP, BGP), it will choose the route with the lowest administrative distance.
- The route with the lowest AD will be placed in the routing table.
Comparison of Routing Protocols
- Directly connected networks: directly connected to the network interface card (NIC) of a router.
- Static routes: manually configured routes that require manual changes when networks change.
- Interior gateway routing protocols (IGRP): used internally in organizations, e.g., RIP, EIGRP, OSPF, IS-IS.
- Exterior gateway routing protocols (EGRP): used between service providers on the internet, e.g., BGP.
Summary
- BGP is a dynamic routing protocol used to share routes between service providers on the internet.
- BGP has a better administrative distance than most interior gateway routing protocols.
- A router will choose the route with the lowest administrative distance from multiple sources.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Learn about the Border Gateway Protocol, a dynamic routing protocol used to share routes between service providers on the internet, including its characteristics and functions.