Exterior gateway protocols

Why are exterior gateway protocols used?

To communicate data between routers representing edges of an autonomous system.

What are Autonomous system numbers assigned to?

Individual autonomous systems.

What are Autonomous system numbers?

A 32 bit #, but unlike IPs, they are normally referred to as a single decimal number instead of being spilt out into readable bits.

What are the two reasons ASN arent split up compared to IPs?

Ip addresses need to be able to represent a network id and a host id portion for each number. An ASN never has to change in order for it to represent more networks or host, just the core internet routing tables that have to be update to know what the asn represents ASNs are also looked at far less than by humans than IPs are.

What is the difference between interior gateway protocols and exterior gateway protocols?

Routers sharing data using Interior gateway protocols all fall under control of the same organization. Routers that use exterior gateway protocols when they need to share information across different organizations

What are the #1 goals of core internet routers?

Since autonomous systems are known and defined collections of networks, getting data to the edge router of an autonomous system is the number 1 goal of core internet routers.

Internet Assigned Numbers Authority (IANA)

An American corporation who oversees global IP address allocation, Autonomous system number allocation, root zone management in domain name system, and other Internet protocol related things.

What is the internet?

An enormous mesh of autonomous systems and at the highest levels, core internet routers need to know about autonomous systems in order to properly forward traffic.