Summary of various dynamic routing protocols

This article will briefly introduce various dynamic routing protocols including OSPF, RIP, BGP, IS-IS, and EIGRP protocols, which will help readers understand and master various dynamic routing protocols.

2. OSPF protocol

(1) What is OSPF

OSPF (Open Shortest Path First) is an Interior Gateway Protocol (IGP) used for routing within a local network. OSPF is generally faster and more reliable than other interior gateway protocols such as RIP.

(2) Working principle of OSPF

OSPF (Open Shortest Path First) is a link state routing protocol that uses Dijkstra's algorithm to determine the best path. The main feature of the OSPF protocol is based on link status, that is, the router sends a link status advertisement (LSA) to notify the router of changes in network status, so that the router can calculate a new shortest path.

(3) Characteristics of OSPF

        1. Calculate the best path according to the network topology and use the Dijkstra algorithm for algorithm calculation
        2. Support VLSM, which can divide the network into subnets to avoid the waste of IP addresses
        3. Can support large-scale networks because it can control the flooding of routing information and update
        4. Support multiple route marking methods, including Type of Service (TOS) and Differentiated Services (DiffServ)
        5. All routers have the same view of the network status

(4) Use of OSPF

        1. Configure the OSPF router ID
        2. Configure the area ID, which helps to divide the network topology
        3. Configure the network address, mask, priority, etc.
        4. Monitor and adjust the performance of the OSPF router

(5) Advantages of OSPF

        1. Support VLSM, which can reduce the waste of IP addresses and save address space.
        2. Can handle large-scale networks while providing good scalability and can be expanded to more than 100 routers.
        3. The router can quickly understand the topology information of the network and understand the latest changes in the network by updating LSP (Link State Message).
        4. It has automatic fault detection and recovery mechanism, which helps to improve the stability and reliability of the network.

(6) Summary

In short, OSPF is a powerful and flexible routing protocol, and it is one of the most commonly used protocols on the Internet. It covers the routing distribution of most enterprise networks and ensures the fast, timely and secure transmission of data in the network. Through the use of OSPF, network administrators can easily control the routing traffic in the network, thereby ensuring the smoothness and stability of the network. (For more detailed information about BGP, please view R&S, Datacom HCIP｜OSPF protocol )

3. RIP protocol

(1) What is RIP?

RIP (Routing Information Protocol) is a distance vector-based routing protocol that was widely used in the early days. RIP works at the third network layer of the OSI model and is used to select routes in IP-based networks. RIP is characterized by simplicity, ease of configuration and implementation, but it also has some limitations.

(2) Working principle of RIP

RIP determines the best path by using a distance metric, namely hop count. RIP routers use the RIP protocol to exchange network information known to each other. Each router maintains the routing table by sending and receiving RIP messages. When the router discovers that the network topology has changed, it updates the routing table and notifies other routers.

(3) Characteristics of RIP

        1. RIP is a protocol that is simple and easy to configure and implement. It is suitable for small networks. The initial configuration step is that a router only needs to configure RIP.
        2. RIP is based on the distance vector algorithm and determines the best path through the number of hops. It is suitable for small LANs with few routers.
        3. The RIP protocol is based on UDP protocol transmission and uses password authentication to protect the security of the protocol.

(4) Limitations of RIP

1. The RIP protocol is an algorithm based on distance vector and is a traditional routing protocol. It does not support more routing algorithms, such as correlation and fairness routing algorithms.
2. RIP can support up to 15 hops and is suitable for LAN environments, but cannot cover larger networks well.
3. RIP has a slow convergence time, so it is not suitable for large networks and is prone to loops and even "RIP necrosis".

(5) Use of RIP

        Using the RIP protocol requires the following steps:
        1. Start RIP on the router.
        2. Configure RIP protocol attributes, including RIP version number, network ID, network mask, etc.
        3. Wait for the router to collect information and update the local routing table.

(6) Summary

RIP protocol is a simple and easy to configure and implement protocol, suitable for small local area networks. However, in larger-scale networks, RIP's limitations become more apparent, and as a result, RIP has been widely replaced by other more advanced and robust protocols such as OSPF, BGP, and EIGRP. (For more details about OSPF, please view R&S, Datacom HCIP｜OSPF protocol )

4. BGP protocol

(1) What is BGP?

BGP (Border Gateway Protocol) is a routing protocol used between different autonomous systems. It is a path-based routing protocol that selects paths and controls routing decisions for TCP/IP-based networks. The BGP protocol is widely used for routing between edge routers in the Internet, ensuring that all networks in the Internet can correctly connect, transmit, and exchange data.

(2) Working principle of BGP

The BGP protocol works on the fourth transport layer of the OSI model. Communication between BGP routers uses TCP port 179 for communication. The BGP protocol uses AS (autonomous system) paths in the network topology to determine the best path. BGP routers broadcast the network range within their own AS to nearby BGP routers, and also request routes from other ASs. BGP is not suitable for routing within the same AS, it is only suitable for routing between different ASs.

(3) Characteristics of BGP protocol

        1. BGP supports two data transmission modes that integrate public relay points (IBGP) and external relay points (EBGP) to better complete the execution of cross-autonomous system routing.
        2. The BGP protocol has certain flexibility, can choose multiple paths, and provides better quality control and security guarantee for the user network.
        3. The BGP protocol can achieve more precise routing selection in the network, thereby improving the efficiency and stability of the network.
        4. BGP also supports policy control, selects routes and paths, and provides advanced functions such as filtering, aggregation, and redirection.

(4) Application of BGP protocol

The BGP protocol is one of the most important routing protocols in the Internet. It is highly scalable and secure and is a standard protocol for interconnection between autonomous systems in the Internet network. BGP is widely used in building interconnected networks between Internet Service Providers (ISPs) and large organizations. It can ensure the interconnection and data exchange between various autonomous systems, and provides better network solutions for enterprise networks, the Internet, and telecom operators.

(5) Advantages and disadvantages of BGP protocol

The BGP protocol plays an important role in the Internet. Its advantage is that it can provide better routing capabilities, policy control capabilities, reliability and flexibility. However, the disadvantages of BGP are that its convergence speed is slow and is limited by factors such as network topology and the number of data packets. It requires highly skilled administrators to configure and manage it.

(5) Summary

The BGP protocol is one of the important infrastructures supporting the Internet. It has high scalability, reliability and security. The use of BGP protocol can improve the efficiency and stability of the network, thereby better meeting the needs of enterprises, network operators, etc. in network topology construction and data exchange. (For more detailed information about BGP, please view R&S, Datacom HCIP | BGP Protocol (1) and R&S, Datacom HCIP | BGP Protocol (2) )

5. IS-IS protocol

(1) What is IS-IS

IS-IS (Intermediate System to Intermediate System) is a communication protocol that adopts the working mode of Link State Routing Protocol and is a standard that supports routing between autonomous systems in the Internet communication architecture. protocol. The following will introduce the working principle, characteristics and application scenarios of IS-IS.

(2) Working principle of IS-IS protocol

1. Connectivity between routers: The IS-IS protocol makes routing decisions through LSPs (Link State Packets sent by each router) in different areas. Therefore, the IS-IS protocol needs to ensure that all routers are evenly connected. There is connectivity.

2. Generation and propagation of LSP: The IS-IS protocol stipulates that each router needs to broadcast LSP to surrounding routers on a fixed basis. The generated LSP records the network topology information that the current router is connected to, and also records the LSP sent by neighboring routers to itself. Timestamp. Then the surrounding routers forward the newly generated LSP to its neighboring routers.

3. Convergence time: The router needs to update the LSDB (Link State Database) when receiving the LSP. Each router node uses the SPF (Shortest Path First, shortest path) algorithm to calculate the shortest path to all other routers. , the shortest path tree is obtained, so that the weights of each destination to all potential paths can be parsed, and the routing information management is continuously calculated, updated and converged.

(3) Characteristics of IS-IS protocol

1. Flexible network topology design: The IS-IS protocol network can be divided into multiple connection domains, and each connection domain can run an instance of the IS-IS protocol independently, thus achieving a more flexible network topology design. At the same time, the IS-IS protocol can also handle situations involving large amounts of calculation and complex networks.

2. Support IPv4 and IPv6 protocols: IS-IS protocol can support IPv4 and IPv6 protocols, which allows it to maintain strong application advantages in the process of network upgrade and development.

3. High availability: The IS-IS protocol can still provide highly available, efficient and more stable network connections while supporting high-bandwidth and high-speed data transmission and traffic.

4. Simple and easy to implement: Compared with other network protocols, the IS-IS protocol is simple to configure, relatively easy to implement, and has good scalability in routing and forwarding.

(4) Application scenarios of IS-IS protocol

1. Enterprise internal network: IS-IS protocol is suitable for various large enterprise internal networks and can provide enterprises with high-speed, efficient and secure routing.

2. Between adjacent autonomous systems in the Internet: The IS-IS protocol is widely used in the Internet. It can enable the routing information between different autonomous systems to be transmitted and updated in a timely and accurate manner.

3. Telecom network operators: The IS-IS protocol can be used for routing management and transmission of telecom network operators to provide more optimized and stable communication services.

(5) Summary

In short, the IS-IS protocol, as a communication protocol, has the advantages of flexibility, efficiency, stability and security, and has broad application prospects. It is suitable for large enterprise networks, the Internet, and telecommunications network operators.

6. EIGRP protocol

(1) What is EIGRP?

EIGRP (Enhanced Interior Gateway Routing Protocol) is a Classless Inter-Domain Routing Protocol that is widely used in small and medium-sized enterprise networks and Internet service provider networks to achieve optimized routing paths and minimum reduce network congestion. The following will introduce the working principle, characteristics and application scenarios of the EIGRP protocol in detail.

(2) Working principle of EIGRP protocol

1. Connectivity between routers: By using multi-path routing technology, the EIGRP protocol can improve the reliability and speed of routing decisions and ensure connectivity between all routers.

2. Loop elimination and load balancing: When two or more paths exist, the EIGRP protocol uses the path equal to the smallest cost instead of using the extensive link state packet (LSD) method. The EIGRP protocol also provides the ability to balance routing and load sharing, which can effectively eliminate loops and network congestion in the network.

3. Reachability check and backup path: The EIGRP protocol checks all paths in the network through the reachability check mechanism. If a path is found to be unreachable, the system will automatically switch to other available paths. At the same time, the EIGRP protocol can also find alternative paths in the network to ensure the high availability and reliability of routing information.

(3) Characteristics of EIGRP protocol

1. Efficient: The EIGRP protocol uses incremental routing updates. When the network topology changes, only necessary routes will be updated, thus achieving fast network updates and responses.

2. Scalability and flexibility: The EIGRP protocol can be expanded to larger-scale networks, and independent routing measurement parameters can be configured for each network, thus achieving better flexibility and scalability.

3. Security: The EIGRP protocol has a password authentication security mechanism and provides data transmission encryption and authentication when exchanging routing information between routers.

4. Support IPv4 and IPv6: The EIGRP protocol can support both IPv4 and IPv6 protocols, thus achieving better network compatibility and future development.

(4) Application scenarios of EIGRP protocol

1. Small and medium-sized enterprise network: It is suitable for routing management and traffic control of the internal network of small and medium-sized enterprises, and can provide an efficient, secure and scalable network topology.

2. Internet: The EIGRP protocol is widely used in Internet service provider (ISP) networks. It can optimize routing paths and reduce network delays, accelerate data transmission, and improve network operation efficiency.

3. Data center network: The EIGRP protocol can help data centers build a more efficient and flexible network topology, while reducing network congestion and improving network performance, thereby providing a better data transmission experience.

(5) Summary

In short, the EIGRP protocol is an efficient, scalable and secure routing protocol. It is suitable for small and medium-sized enterprise networks, Internet and data center networks, and provides good compatibility and development by supporting IPv4 and IPv6. Thus becoming one of the excellent choices for network managers.