An autonomous system, also known as AS, is a collection of connected Internet Protocol resources managed by network operators. It represents a single administrative entity which has clearly identified routing policies.
An AS is defined mainly by its number, called the ASN. It is a 32-bit integer (0 to 4294967295) unique to each autonomous system. Some numbers are reserved for private use and must not be routed on the Internet.
In Peering Manager
Inside Peering Manager, you create autonomous systems that you want to peer
with. Your own ASN numbers must be provided by checking the
field. For each AS that you create, the following properties can be configured
(n.b. some are optional):
ASN: unique autonomous system number of the entity.
Name: human-readable name attached to an AS.
Affiliated: whether or not you manage said autonomous system.
IRR AS-SET: the set of other ASNs that can be found behind this AS.
IPv6 Max Prefixes: a zero or positive integer which defines the maximum number of IPv6 prefixes to receive from the AS.
IPv4 Max Prefixes: a zero or positive integer which defines the maximum number of IPv4 prefixes to receive from the AS.
General Policy: the General Peering Policy of an Autonomous System. This is auto synced from PeeringDB and is not user changeable.
Import Routing Policies: a list of routing policies to apply when receiving prefixes from the AS.
Export Routing Policies: a list of routing policies to apply when advertising prefixes to the AS.
Communities: a list of communities to apply on prefixes received from or advertised by sessions with this AS.
Properties To Synchronise From PeeringDB: some properties such as the name, the IRR AS-SET and prefix limits can be synchronised from the AS' PeeringDB record.
Tags: a list of tags to help identifying and searching for an AS.
Comments: text to record some notes about the AS. Can use Markdown formatting.
Note that the best way to keep all of these properties up-to-date is to use the PeeringDB integration that can synchronise some of them automatically.