What Is IPTransit
IP Transit consists of two services, one being the advertisement of customer routes to other ISPs (Internet service providers) and the other part being advertising routes to other ISPs. Default routes provide a means of the router knowing where to send traffic destined for other networks on the internet. this sometimes does not always happen. This means they are soliciting the outbound traffic from the customer towards the other networks. IP Transit could be detailed as like so.
There is a number of other technical aspects to transit that you need to ask your self or provider about if you have it or need it. A duel IP stack is where you use a transitional protocol for IPv4 to IPv6 within the operating system. One for each of the versions of IP. The implementation may be different for each host some using a hybrid system while others implementing IPv4 and IPv6 seperatly. The latter is the more common implementation in modern operating systems on both the server and for an end user.
You may need to consider routing protocols and whether your happy for your route to already pre-defined on where to go using one route. this may be for cost purposes or because its the only route out of the network and have to go through someone elses router before your out onto the internet BGP or Border Gateway Protocol or BGP is the core routing protocol used on the internet by holding and updating a table of IP networks or prefixes this is used to designate the availability of a network. By using an Autonomous system that has a set of connected IP routing prefixes controlled by one or more network operators and presents the common routing policy to the internet. BGP is a vector protocol that dynamicly updates path informaiton. If an update ends up being looped through a node is easily picked up and discarded and this is used by other routing protocols to help stop any infinity loops.
You have peering, this is where networks that are separately owned and operated are interconnected to exchange the traffic between each other. The actual definition is settlement free or sender keeps all, which means the owners of each network will pay the other to exchange data with each other. meaning that the revenue comes from their own customers. But now many people miss use the word Peering and actually mean it where there is some form of payment involved. The term “settlement free peering” is now commonly used to make sure that confusion does not occur over what is being advertised or described.
It is through metro ethernet, that datacentres talk to each other. Because the internet uses a common framework for the use of unique IP addressing and using the BGP routing protocol. You find that relationships form between networks and so can be placed in three categories. Transit is where you pay money to another network for internet access. Peering where you swap and exchange traffic for other customers for free and of mutual benefit, or as a customer where you receive payment from another network to gain internet access. So for a network to reach any other network on the internet it must sell transit, directly peer with the network, or finally pay for transit from another network and go round this loop until you finally reach the destination.