Common Internet Router Protocol classifications

For the term router protocol, probably a lot of people have been familiar with, especially the current network development quickly, Internet Router Protocol is also constantly improving, but also appeared a lot of new features. The wide application of information technology in various fields has promoted the rapid development of information exchange network, in which the Internet is the biggest beneficiary.




The main node device of the
Internet network is the router, which determines the forwarding of the data through routing. The forwarding strategy is called routing (routing), which is also the origin of the router name (router, forwarding). The decision to forward the method can be artificial designation, but the person for the specified workload, and can not take flexible strategies, so the dynamic router protocol came into being, through the transmission, analysis, calculation, selection routes to achieve routing discovery, routing, Routing and load sharing functions.





RIP, OSPF, and BGP protocol





router protocols that are running on the internet today are RIP, OSPF, and BGP. RIP, OSPF is an internal gateway protocol that applies to the operation of a single ISP's unified router protocol, and a network operated by an ISP is called an autonomous system (AS). BGP is a router protocol between autonomous systems and an external gateway protocol.





RIP is the longest-launching router protocol and the simplest router protocol. It is the acronym for routing Information Protocol, which mainly transmits routing information (routing table) to broadcast routes: every 30 seconds, broadcast a routing table, maintain the relationship between neighboring routers, and compute its own routing table based on the routing table received. RIP is simple to run and applies to small networks, and rip is partly used on the Internet. 3lian.com




The
OSPF protocol is an abbreviation for "Open Shortest Path First". "Open" is for some manufacturers at that time "private" router protocol, and it is because of the openness of the Protocol, the OSPF today to create a strong vitality and a wide range of uses. It obtains the network information by transmitting the link state (connection information), maintains a network topological graph, and obtains the routing table by using the minimum spanning tree algorithm (SPF algorithm). OSPF is a relatively complex router protocol.





In general, OSPF and RIP are the router protocols within the autonomous system and are suitable for use by a single ISP (autonomous system). Generally speaking, the entire internet is not suitable for running a single router protocol because each ISP has its own interests and is unwilling to provide detailed routing information for its own network. In order to ensure the interests of each ISP, the standardization organization developed the router protocol BGP between ISPs.





BGP is the abbreviation of "Boundary Gateway Protocol", which deals with routing delivery between ISPs. It is characterized by a rich routing strategy, which is not possible in RIP, OSPF, and other protocols, because they require global information to compute the routing table. BGP through the ISP boundary of the router plus a certain strategy, select the filter route, RIP, OSPF, BGP and other routes sent to each other. A global, extensive internet is an instance of the BGP process of routing between multiple ISPs. The advent of BGP has led to a major change in the Internet, which connects multiple ISPs organically and truly becomes a worldwide network. The side effect is the Internet routing explosion, and now the Internet route is probably 60,000, which is the number after the "aggregation". Configuring BGP requires a very good understanding of user needs, network status, and BGP protocols, as well as--need to be very careful, BGP runs at a relatively central position, and if it goes wrong, it can cause a lot of damage!





a new transmission mode-multicast (multicast) is developed to adapt to Internet network One-to-many transmission applications such as weather forecast and network conferencing. Multicast is suitable for one to many transmission environment, but also can be applied to many, many to one. Multicast forwarding is mainly determined by routers, and routers determine the so-called downstream in two ways: decide whether there is a downstream of the host (user), pass the Multicastclient (IGMP) protocol, decide whether there are indirect users, that is, through the "downstream" router with the team, The router determines whether to forward data to the downstream router through a multicast router Protocol message notification. It can be seen that the application of multicast router protocol in the second way is the key of large scale network multicast forwarding. The multicast router protocol should at least correctly notify the group members information and form a globally unified routing topology. 3lian Material





Dense mode for small networks, the assumption is that the whole network has very "dense" team members exist, the use of Radio + pruning work strategy. The default assumption is to forward the data to all downstream, and then remove the interface from the downstream list when it receives a clear pruning message from a downstream stream. In general, the forwarding path should be a "source" as the root, the group members of a tree foliage. Dense-mode router protocols include DVMRP, MOSPF, and PIMDM.





sparse mode is a widely used situation on the Internet. After all, for Internet networks, no more than 1% of the machines need to be received at any one time in a multicast application. Sparse mode defaults All machines do not need to receive multicast packets, only explicitly specify the need to be forwarded, this can really apply to the "sparse" considerations. The main forwarding idea of all sparse-mode protocols now is that all of the same messages are forwarded in the same path, that is, first sent to a converging point (or kernel), and then forwarded along a shared tree that is rooted to the aggregation point. The sparse approach to router protocols includes PIMSM and CBT.





can be no exaggeration to say that the router protocol supports IP and supports the Internet. Without a router protocol, the Internet would be a messy world, and it would not be as convenient and fast as it is today. But multicast has created a new development foreground, will become the main force that guides the internet future.