table of a router, when there are many Flap conditions, the load on the router equipment will generate a great deal of pressure. Based on my practical experience, when a high-end router computes BGP routes, the CPU load is basically 80% ~ About 90%, or even 100%, occupies almost all CPU resources. Although most of the high-end routers distribute the routing comp
16 bits starting from the left end of the address. The introduction of CIDR simplifies Routes Aggregation ), route aggregation is actually a process of combining several different routes, so that the route entry is changed from advertised to advertised, reducing the route table size 。
When a route is updated, the BGP routing
ensure that routing information is properly broadcast to each router. According to this principle, the total number of I-BGP sessions in an autonomous domain is NX (N-1)/2 (n is the number of routers running I-BGP), and when n grows, the number is staggering: 100 routers, the number of sessions is 4950. This is a huge burden for network devices, and it will comp
1. Introduction
BGP is a routing protocol between autonomous systems. The Network accessibility information exchanged by BGP provides sufficient information to detect routing loops and make decisions based on performance precedence and policy constraints. In particular, BGP
BGP routing protocolPublic AS: 0-64511 PRIVATE: 64512-65535 China Telecom: 4134 China Netcom: 9929BGP use 1. Cross different, management issues 2. OSPF Support 1 W + routes ISIS support 2 W + routes 3. High Policy controllability 4. Strong scalability free public network route table route-server.ip.att.netreviews do not use B
, 2000, and 5 AS 1.1.1.0/12." The most important thing about BGP is that AS-Path itself uses a mechanism to prevent product routing loops, and the router does not import any routes already included in the AS-Path attribute.
For a vro, if you want to import a route and then tell it to a partner in the peer-to-peer relationship, you must before declaring this route, first, append your AS number to this AS-Pat
topology changes, OSPF can quickly recalculate the path, generating only a small amount of routing protocol traffic. Key Benefits: Fast convergence speed, no jump limit; Support Service type routingProvides load balancing and identity authenticationApplicable environment Large-scale, environment-complex Internet3.BGPProtocolBGP (Border Gateway Protocol,Border Gateway Protocol ) is a routing protocol b
respectively, continue to the next step.
8: BGP preferentially selects the path with the lowest measurement value for the next hop IGP. (Both EBGPpeer and IBGPpeer, or both EBGP and IBGP are compared)
9: When the eight routing principles listed above fail to select the optimal route, maximum-paths [ibgp]
To achieve load balancing, routes received by both IBGP and EBGP must be exactly the same as-path, and
With the development of the Internet in China, the connection between ISP service providers and Internet is also changing. On a network connection, from a single connection to the Internet via multiple telecommunications companies, in terms of routing protocols used, from the use of static routing protocols to the use of BGP (Border Gateway Protocol). How does th
selection of N7K-1 flow is based on the routing principle of the last "select a smaller neighbor address routing", N7K-1 neighbor address is 30.207.7.41, N7K-2 is 30.207.7.45, so select the N7K-1. 4. Add a maximum-path ibgp 5 in the BGP configuration. A maximum of five equivalent routing loads are allowed for troubles
up with a solution, that is, to use the "routing policy" to increase the management distance of Route entries sent by EBGP 99.99.99.0, alternatively, the Management Distance from the 99.99.99.0/24 route entries received by the Network in the same way is smaller than that of the EBGP 20.
The routing policy is to make a routing policy based on the content of the r
connection interface. It sends the number to R1 and R1 searches for the route and finds the route matching 10.6.0.0/16, the next hop is 10.0.0.2, not a direct connection interface. The next hop is the destination IP address for recursive search routing, matching 10. 0 .. 02/32 route. The next hop is 10.0.1.5, which is a direct connection interface. data is sent to R3. R3 searches for the route based on the target IP10.6.6.1. If no matching item is fo
automatically expand into three processes, which act as parent processes, process session processes, and take charge of route computing processes. The parent process runs as root, while other processes are not.650) this. width = 650; "src =" ../attachment/201201/162320508 .jpg" border = "0" alt = ""/>From this, we can see that the parent process is responsible for communicating with the peer vro, querying and updating the route table, and processing
determine whether to publish secondary network segments) neighbor 12.1.1.2 remote-as 2 neighbor 12.1.1.2 update-source Serial1/0 neighbor 12.1.1.2 advertise-map dist_out2 exist-map line2 (if the external line 2 is normal, the route entry of the external line 2 will be re-distributed to the bgpl route table, and the secondary route will be advertised. If 2 is normal, and it can be advertised from s1/0 [first-line port] Neighbor
1. Route Selection Protocol
The core of routing protocol is routing algorithm, the router uses routing protocol to generate routing table, which can realize the "best" path of the network packets.
2. Classification of routing
First, the experimental topology:Second, the experimental requirements:1, R4, R1, R3, R2 respectively in the BGP process deployment neighbor Send Community attribute command;2, R4 deployment ACL crawl 4.4.4.4 traffic, Route-map named as, call ACL, set community Local-as, and call Route-map as out in the BGP process;3, verify: R1, R3 have 4.4.4.4, but R2 have no 4.4.4.0 route entry?Third, command deployment:
complete the three-to-TCP handshake.
To achieve passive measurement, each measurement interface on the device is configured with a virtual IP address (fictitious IP address,vip). Returns an 1x1 pixel GIF image when the address is accessed via HTTP or HTTPS. Pathcontrol provides this GIF directly, measuring the time it took to establish a TCP call with a client computer. As long as the VIP address is embedded in an href on the Web page, the measurement begins once a client requests the page. Th
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