Analyze how the OSPF protocol prevents routing loops

1.The algorithm of the protocol itself belongs to the link state algorithm, that is, there is only one active path from one point to another, which essentially eliminates the generation of loops.

Zone division is supported, and area 0 is the backbone area, and the non-backbone area must theoretically be directly connected to the backbone area.

The originator of the route can also be identified through the router ID, which can prevent loops to a certain extent.

OSPF is protected from the inside of the AS, while other routes introduced by OSPF are not 100% sure to prevent loops.

That's all I have to think of for the time being, if you have a more detailed answer, you are welcome to add.

Upstairs is already very comprehensive.

Before the advent of OSPF, RIP (Routing Information Protocol) was widely used as an internal gateway protocol.

Because RIP is a routing protocol based on distance vector algorithm, it has problems such as slow convergence, routing loop, and poor scalability, so it is gradually replaced by OSPF.

As a state-of-link protocol, OSPF can solve many problems faced by RIP. In addition, OSPF has the following advantages:

OSPF uses multicast to send and receive packets, which reduces the impact on other routers that do not run OSPF.

OSPF supports Typeless Interdomain Routing (CIDR).

OSPF supports load balancing for equal-cost routes.

OSPF supports packet encryption.

Due to the above advantages, OSPF is quickly accepted and widely used as an excellent internal gateway protocol.

OSPF Routing Association.

Protocol is a link-state routing protocol used for Internet Protocol (IP) networks. The protocol uses the Interior Gateway Protocol (IGP) of the link-state routing algorithm and works inside a single autonomous system (AS).

As a link-state routing protocol, OSPF transmits link-state advertisement (LSA) packets to all routers in a certain area, which is different from distance vector routing protocols. A router that runs the distance vector routing protocol passes some or all of the routing table to the router that is adjacent to it.

This question is a bit too general and can be addressed from many angles.

1. OSPF is an IGP routing protocol, that is, an internal routing protocol that runs inside the same AS, and the routing protocol between AS is BGP.

2. OSPF is a link-state routing protocol and a dynamic routing protocol. The SFP algorithm is the shortest path first.

The first classification is to confuse the routing protocols, which are divided into IGP (internal routing protocol) and BGP (border gateway protocol), RIP OSPF EIGRP all belong to IGP, that is, the routing protocol used in an autonomous system, and BGP is used by autonomous systems to access each other, which involves ISP operators. It can be understood that an autonomous system is a large router, and the protocol running in the middle of these routers is BGP. The autonomous system here is only an autonomous system in the physical sense, such as China Unicom Telecom network RIP is a distance vector routing protocol, which achieves network-wide interoperability by exchanging explicit routes, that is, the routes he obtains are sent through neighbors.

Similar to asking for directions, OSPF is a link-state routing protocol and does not send routing information. Instead, the route entries are computed on their own by sending the link state LSA. Similar to how to go after GPS is sent to the other party's direction, the specific way to go is calculated by the local system.

SPF algorithm, shortest path first.

Algorithm. Open shortest path priority protocol.

When there is no route, it will be thrown above the default.

Tells all routers in the domain that the egress is in, i.e. when the router receives an unknown route entry, it will send it to the egress direction.