Un Autonomous System (AS = Autonomous System) It is a network or set of networks under a single administrative control and with a coherent routing policy. In simpler terms, an Autonomous System is a network that can make independent decisions about how to route data traffic on the Internet.
At the end of the article you will find a small test that will allow you assess the knowledge acquired in this reading
Un AS It is identified by a unique number called Autonomous System Number (ASN). These numbers are assigned by regulatory bodies, such as the Internet Registry for Assigned Numbers (IANA) or the Regional Internet Registries (RIR).
How do I obtain an ASN?
The assignment of Autonomous System Numbers (ASN) in the South America region is carried out by LACNIC (Latin American and Caribbean Internet Addresses Registry).
LACNIC is one of the five Regional Internet Registries (RIRs) responsible for the allocation and administration of Internet resources in different regions of the world.
LACNIC is responsible for managing IP address and ASN resources for the region of Latin America and Caribbean, including the countries of South America. This involves assigning blocks of IP addresses and Autonomous System numbers to organizations and Internet service providers (ISPs) that operate in the region.
If you are interested in obtaining an Autonomous System number for your organization in South America, you must contact LACNIC to begin the application and assignment process.
You can visit the LACNIC website (www.lacnic.net) for more information on the requirements and procedures for obtaining an ASN in the region of South America.
What benefits does having an ANS give me?
Having an Autonomous System provides several benefits, such as:
1. Routing control:
An Autonomous System allows you to make routing decisions and control how data is transmitted within the network. This allows you to optimize network performance, efficiency and security.
2. Connectivity and peering:
An Autonomous System facilitates interconnection with other Autonomous Systems, such as Internet Service Providers (ISPs), allowing greater connectivity and access to a wide range of resources on the Internet.
3. Improved redundancy and availability:
By having an Autonomous System, a redundant and diversified routing configuration can be implemented.
This ensures that if a connection or route fails, the network can use alternative routes to maintain connectivity and minimize service interruptions.
4. Performance optimization:
An Autonomous System allows specific routing policies to be implemented to direct traffic through the most efficient routes and optimize the use of available network resources.
5. Increased security:
By having an Autonomous System, you have greater control over the security of the network. Filters and routing policies can be implemented to protect the network from attacks and limit unwanted traffic.
ASN range
These are the ranges of both 16-bit and 32-bit Autonomous Systems Numbers (ASN):
ASN range (16 bits) | Description |
1-64511 | Assigned by IANA (Internet Assigned Numbers Authority) |
64512-65534 | Reserved for private use and testing |
65535 | Reserved for 16-bit ASNs that cannot be used |
65536-65551 | Reserved for special purposes |
ASN range (32 bits) | Description |
65552-131071 | Assigned by IANA (Internet Assigned Numbers Authority) |
131072-4199999999 | Assigned by Regional Internet Registries (RIRs) |
It is important to note that the 16-bit range has limitations in the number of ASNs available, which led to the implementation of the 32-bit format to allow a greater number of assignments.
It should be noted that the Regional Internet Registries (RIRs) are responsible for assigning Autonomous System numbers in the 32-bit range. If you wish to obtain an Autonomous System number, you must contact the Regional Internet Registry corresponding to your region to begin the application and assignment process.
Routing protocol
The routing protocol used between autonomous systems on the Internet is the Outer Edge Gateway Protocol (BGP). BGP is a link-state routing protocol used to exchange routing information and make routing decisions on the Internet.
BGP is specifically used for routing between different autonomous systems, which involves exchanging routing information and making decisions on propagating routes across multiple routing domains. BGP is a route vector-based protocol and uses attributes to describe routes and make routing decisions.
Autonomous systems use BGP to exchange routing information, advertise networks, and select the best routes to send traffic between them. BGP allows network administrators to control and optimize the flow of traffic on the Internet by establishing routing policies and making informed decisions about how routes are propagated and preferred paths are chosen.
It is important to note that BGP is a complex protocol and is designed for large-scale use on the Internet.
Autonomous systems can use other internal routing techniques, such as OSPF (Open Shortest Path First) or IS-IS (Intermediate System to Intermediate System), for routing within a particular autonomous system. However, for routing between autonomous systems, BGP is the predominant protocol used on the Internet.
configuration example
Below is an example of CLI configuration to establish an Autonomous System in MikroTik RouterOS:
/routing bgp instance
set default as=65001 name=bgp1
/routing bgp peer
add address-families=ip as=65002 name=peer1 remote-address=
In this example, we have configured an Autonomous System with ASN 65001 in MikroTik RouterOS. Then, a BGP neighbor (peer) with ASN 65002 has been configured and its IP address and authentication key have been specified.
Please remember that this is just a basic configuration and specific details may vary depending on your environment and requirements.
Brief knowledge quiz
What do you think of this article?
Do you dare to evaluate your learned knowledge?
Recommended book for this article
RouterOS v7 Advanced Routing Book
Study material for the MTCRE Certification Course, updated to RouterOS v7