Four-tier load balancing and seven-layer load balancing

1, four-layer load balancing and seven-layer load balancing differences

Personal understanding: The Network Seven layer protocol includes, application layer (seventh layer), presentation layer, session layer, transfer into (fourth layer), network layer, data link layer, physical layer. The so-called seven-and four-layer load balancing refers to which layer is based on load balancing. Nginx Reverse Proxy is a seven-layer load balancing, can be divided by the user's request URL, LVs is a four-tier load balancing, based on IP and port number to achieve division. Layer Seven will be smarter because you can get more information and have more filters. But

Application layer Common protocol: TELNET,HTTP,FTP,NFS,SMTP, etc.

Transport Layer Common protocol: TCP, UDP

Reference URL: http://kb.cnblogs.com/page/188170/

2. Technical differences

http://virtualadc.blog.51cto.com/3027116/591396

Personal knowledge:

Technical level: The four layer is the main forwarding, that is, the client and the back-end server established a real connection, the user's request will eventually reach the latter segment of the server. The seven-tier proxy is a proxy server, which is a connection between the agent and the client, the agent and the real server behind the stage. In this case, the four layers are more simple, while the seven layers are more complex.

Application scenario: Layer Seven can be an opportunity for users to balance the actual request, such as picture requests and text requests can be separated, but the configuration is more complex; security, seven layer load can prevent SYN flood attack, because for the total malicious, can be blocked at the agent layer, And the four-tier time is finally directly reached after the real server.

But the seven-tier configuration is complex, and the proxy server is good enough.

3. VRRP and OSPF protocol

VRRP protocol Introduction: http://blog.csdn.net/linyt/article/details/2045755 Virtual Routing Redundancy Protocol

Personal understanding: Put in the load Balancer scenario, the request through the load-balanced router to the back of the machine, load-balanced router If there is a single point of problem, then it is serious. How to ensure that load balancing can be effective, then you can find a set of devices to form a virtual whole. In this whole, one is master and the others are backup. These routers use the VRRP protocol to determine the current status, backup upgrade to master, and other information. If master hangs up, select who will be the new master, which can be filtered by the priority configured by the device itself. Sum up: Through multiple routers virtual into a router to solve the single point of problem, multiple routers through the VRRP protocol to communicate with each other, after the problem, you can quickly determine the next master.

OSPF protocol: Open Shortest Path Priority protocol http://blog.sina.com.cn/s/blog_4a1ef95f010009bj.html

OSPF acts as an internal gateway protocol (Interior Gateway PROTOCOL,IGP) for publishing routing information between routers in the same autonomous domain (AS). Apart from the distance vector Protocol (RIP), OSPF has the advantages of supporting large-scale networks, fast convergence of routes, and less network resources, which occupies a very important position in the routing protocols currently applied.