Troubleshooting of IGRP/VPN Protocol 2

Troubleshooting of IGRP/VPN Protocol 2 07. Why does it mean that VPN is neither a distance vector protocol nor a link status protocol? VPN is an advanced distance vector protocol. It sends and updates route information based on the neighbor router. However, it also saves a route topology table. When the network topology changes, it only sends the changed route information. When the route table changes, the entire route table is updated. 08. Is there a loop in the routing of the OSPF protocol itself? Why? No loop exists in the network. Because it uses the DUAL algorithm, when selecting the optimal path, it is a non-circular path. 09. Is there a difference between the measurement calculation of the ospf and IGRP? What is the difference? The difference is that the value of the OSPF metric value must be multiplied by 256 10 Based on the IGRP value. by sending and confirming HELL0 data packets, VPN establishes a neighbor relationship. What is the update cycle of HELL0 data packets on a WAN or a link with a speed greater than T1? What is the update cycle for low links (less than T1? On a wide area network or a link with a speed greater than T1, the update cycle of HELLO packets is 5 seconds, while that of the T1 link is 60 seconds. 11. What conditions should I meet before I establish a neighbor in the kernel network? The IP address of the link should be in the same subnet, And the subnet mask should be the same. The constant K value at both ends should be the same. The receiver router should be in the same autonomous system as the sender router. 12. What is the meaning of "SRTT, RTO, and Q" in the output of "show ip VPN nei" in the image "in the kernel of the kernel? SRTT (smooth round-trip time): the average value of the time when a data packet is sent and the time when a data packet is received. RTO: The time for sending a data packet and waiting for response. Q: The number of data packets sent to the remote router. 13. What is FD, RD, and FC? FD: feasible distance. The measurement value calculated from the current vro to the remote vro. RD: The reported distance (also called the advertised distance). The measurement value from the neighboring vro to the remote vro. FC: feasible condition, the measurement value of the distance advertised by the neighbor should be smaller than the feasible distance calculated by the neighbor and used to select a feasible route to accelerate route convergence. 14. What is a passive route and what is an active route? Why does it generate an active route? Active route: The route table changes due to the loss of Route entries or a change in the network topology. If no feasible route entry is available, the route table enters the active query status, find the lost route information, which is called active route query. Passive route: In the route table, the remote route information entries that can be reached through the next hop. 15. What is the state mechanism of the DUAL algorithm? VPN uses the Diffusion Algorithm (DUAL) to calculate the optimal route information of a non-ring network. Unlike the traditional distance vector protocol, it saves a topology table to speed up convergence. 16. What is the query of the kernel, and what is the function of the query? In the query of a route entry in the route table, the query is performed when the route entry is disconnected but no route entry is feasible. 17. Which types of data packets are contained in the network, which are reliable and which are unreliable? Five types of data packets are used in the Network: 1. Hell0 2. Confirm 3. Update 4. query 5. The first two types of data are unreliable, and the last three types are reliable. 18. What is a stuck activity status? In general, what kind of command is used to find the error point? When in a large network environment, the SIA status may occur, that is, the router is always in the query status (also called active status) of the VPN gateway ), when a route query message is sent and no response is received, it is in this status. Generally, this status lasts for three minutes, but for a large network environment, when a neighbor router receives this packet to find the lost route information, it finds that it is not in progress and sends the query information to other neighbors. This keeps sending, and there may be network boundaries, are there any lost route information entries found. But there are several reasons for this SIA: 1. It may be that the remote link is DOWN. 2. Problems at the first or second layer. In general, run the command to view the show ip VPN topo active 19 on each adjacent router. What will happen if the K value does not match in OSPF? The OSPF neighbor cannot be created normally. 20. When configuring the Server Load balancer and non-Server Load balancer, which of the following commands can be enabled after the variables are configured for the configuration of the Network Load balancer and the non-Server Load balancer that is proportional to the link measurement value? Traffic-share min Traffic-share l