Ccna-3-cisco Static Routes

Routing protocols are used for router selection paths and for managing routing tables, which support routable protocols by sharing routing information between routers. Routing information is passed between neighboring routers to ensure that all routers know the path to the other routers. In a word, the routing protocol creates the routing table, describes the network topology, and the routing protocol works in conjunction with the router to perform Routing and packet forwarding functions. The routing protocol can be considered as an application to calculate the path of the router:

1. The Routing Protocol (Routed protocol) is working at the network layer, and is responsible for encapsulating the packet (TCP/IP) based on the best path

2, routing Protocol (Routing Protocol) work in the Transport layer or application layer, is responsible for learning to obtain the best path.

The key to the router forwarding packet is the routing table:

The routing table indicates the destination network, how to forward (which physical port to send), to the next router or not through other routers to transfer to a directly connected network destination host.

Routing:

To implement a router you need to know: Destination address, source address, all possible paths, best routing path, manage routing information (that is, store non-optimal routing path)

Administrative distance (administrative Distance):

The management distance mainly shows the credibility between different routing protocols. The path where the optimal route is selected when there are multiple reachable path conditions.

• The range of confidence is 0-255. It represents the trustworthiness value of a route selection information. The lower the value, the higher the confidence level. 0 for the most trust, 255 for the least trust.

• Cisco common management distance values: direct connection 0; static route 1;eigrp 90;igrp 100;OSPF 110;rip 120

Routing is divided into static routes and dynamic routes, and multiple protocols are separated in dynamic routing.

Static routes are manually added routing information and do not change

Advantages

1. No administrative overhead on the router CPU

2. No bandwidth usage between routers

3. Increased security (relative dynamic routing to be stable)

Disadvantages

1, must really understand the network

2, for the new network configuration cumbersome

3, for large-scale network workload is huge

• Applications: Small to medium-sized networks with no or small expansion plans

• Static routing configuration:

Router (config) #ip route target network subnet mask next router address (i.e. gateway, interface address of nearest router to subnet)

When you configure a static route, you must configure a reverse path to ensure that there is a return.

Remove route directive: no IP route XXX. (Huawei is all undo)

Instance

router>en

Router#conf T

Router (config) #hostname R1

R1 (config) #interface s0/0/0

R1 (config-if) #ip address 192.168.1.1 255.255.255.0 input addresses

R1 (config-if) #clock rate 64000 Configure clock rates (only required when using packet TRACERT simulator)

R1 (config-if) #no SH open port

R1 (config) #ip Route 2.2.2.0 255.255.255.0 192.168.1.2 Configure static routes

• Use the default route to add the IP classless (no class selection) command (now default)

There are class options (no IP classless):

Drop packets without such a route (e.g. 1.2.3.4, but only 1.1.1.1),

However, if you do not have this class at all, you will also select the default route (for example, 4.4.4.4).

No class selection: The default route is selected for transport without such routing

This article is from the "12155849" blog, please be sure to keep this source http://12165849.blog.51cto.com/12155849/1907083

Ccna-3-cisco Static Routes