I want the three kings bring me an AS

Three years ago I studied routing protocols in the CCNP certification and at the beginning I thought it would be difficult to use and apply this concepts in the real world because I don't work in an ISP. However, I have had the opportunity to use it for the last three years. First, I have to migrate a firewall which used the RIP protocol, next I had to teach the CCNA certification with an unit about routing protocols, I could also configure some BGP routes in the Technological Scientific Network of the Government of Extremadura and some other private companies, and finally, I taught OSPF protocol under Alcatel-Lucent to the engineers of AENA. For this reason, I think the next step could be to manage, operate and configure an AS or Autonomous System.

An autonomous system is a set of network, we can also call it a mini-internet, manages by our own where we can make decisions about traffic flow with policy based routing. If we want an Autonomous System, we have to contact with IANA and RIPE, which are the authorities who give us the Autonomous System Number (ASN)  and public IPs as well. Once administrative tasks have been done, we have to design the topology network and we should think about redundancy, peering, bandwidth, latency and the IP addressing scheme.

When we speak about an Autonomous System we shouldn't think in a particular geographical area or region but an ASN or public IPs, which are announced by routers with the BGP protocol against remote peers. This is the main protocol of Internet, BGP, which is an old protocol that works by trust because anyone can announced routes even if they aren't theirs, like when Google's services were disrupted by routing error. And this is an advantage of having an Autonomous System because we can have the IP addresses regardless where we are, geographically speaking.

As I said, an advantage of having our own Autonomous System could be the flexibility and scalability that we get when we have the possibility to move IP addresses from one area to another without disrupting the services, which is useful in business continuity scenarios along with  Global Server Load Balancing. This is possible when our Autonomous System reaches a whole area with several cities, or it is interconnected by VPN technologies, which allow us to make peering with other Autonomous Systems to get Internet through two or more different service providers.
 
However, there are some disadvantages. First of all, we have to be careful with suboptimal routing because asymmetric routing is common in this kind of scenarios and it's difficult to avoid it. Therefore, we can be delivering traffic through expensive lines or we are not taking the advantage of using the maximum bandwidth available. And another thing to mention is the knowledge we need if we want to manage these complex networks properly.

This is my letter for the three kings this year. We'll see if I can keep learning and playing with these toys to improve my knowledge and myself and enjoy with network and security.

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