Shulou(Shulou.com)06/01 Report--

Theoretical study

Question1: what is the physical composition of a wide area network using DCE and DTE?

In WAN connections, such as routers and computers all belong to DTE devices, while CSU/DSU and Modem belong to DCE devices. Usually by the DCE side to provide clock frequency, signal synchronization, signal control. DCE devices and DTE devices are usually connected by serial lines.

Question 2: what are the communication methods of the WAN? What are the characteristics of each?

(1) Direct Connect: it represents DDN Direct Connect. DDN Direct Connect uses synchronous serial port to connect, which can encapsulate layer 2 protocols such as HDLC, PPP, Frame-Relay, SLIP and so on.

(2) packet switching network: both X.25 and frame Relay packet switching network use synchronous serial port to access the network, X.25 encapsulates X.25 and frame Relay encapsulates Frame-Relay protocol.

(3) Cell switching network: the typical representative is ATM network. For user access, standard ATM equipment can be directly connected or carried out by using ATM concentrator, while non-ATM network can be accessed indirectly by ATM concentrator. The transmission medium used for ATM network access is usually optical fiber. ATM network equipment uses a special ATM interface, and the sub-packaged protocol is ATM protocol.

(4) Circuit switching network: the representative is PSTN network, and the core switching network is composed of PBX program-controlled telephone exchange. it connects the user network and the service provider network through asynchronous Modem. The transmission medium used by the user is usually the telephone line, the line used to connect the Modem to the user equipment is the EIA/TIA-232 serial line, and the router serial port is the asynchronous serial port. The protocol encapsulated by PSTN is HDLC, PPP or SLIP.

What are the characteristics of 3:PPP and HDLC protocols respectively?

HDLC protocol: high-level data link control is a bit-oriented data link layer protocol that transmits data over synchronous networks. It is extended by the International Standardization Organization (ISO) according to the SDLC protocol of IBM. HDLC for error correction is similar to Ethernet, the cisco version of HDLC is more privatized, adding a protocol type domain. Cisco HDLC default WAN interface encapsulation protocol, domain common HDLC structure is similar.

PPP protocol: multi-protocol packets are transmitted over point-to-point connections. Originally designed to provide an encapsulation protocol for IP traffic transmission between two peer nodes, TC PIP protocol sets it as a data link layer protocol used to synchronize data connections instead of the original non-standard data link layer protocol SLIP. In addition to the IP protocol, PPP can also carry the protocol of DECnet or Novel's ipx.

Supports the transmission of synchronous or asynchronous serial links

Support for multiple network protocols

Support error checking

Support address negotiation at the network layer

Support for user authentication

Allow data compression

The advantage of PPP protocol lies in its simplicity and user authentication ability, which can solve the problem of insufficient allocation of IP.

What are the characteristics of 4:PAP and CHAP certification respectively?

PAP:

(1) the password is transmitted in clear text, so the security is low.

(2) it is a second handshake, initiated by the authenticated party, and there are only two processes: request and reply.

(3) PAP authentication is carried out only in the link establishment phase, and once the link is established successfully, no authentication detection will be carried out.

CHAP:

(1) md5 is used for encryption with high security.

(2) three-way handshake is used for authentication, which is initiated by the primary authenticator.

(3) passing one verification is not exempt from inspection for life.

(4) the passwords used by the principal authenticator and the authenticated party must be the same.

Job task description

Companies An and B both have their own independent local area networks and connect with CNC routers respectively (three routers are connected to four subnets), requiring the use of DDN dedicated lines to achieve the project.

Task implementation

1. Network topology design

two。 Device configuration commands (each router is configured separately)

R2 router configuration:

Configure an address for computer A

Configure an address for computer B

Configure R1 with routing entries

Configure R2 with routing entries

3. Single-stage test results

A computer ping router f0gamo interface

R1 router ping R2 router s0amp0 interface

R2ping computer B

4. Comprehensive test results

A computer pingB computer:

5. View the interface status of each router, especially the pin characteristics of the V35 line

View the interface status of the R1 router:

View the interface status of the R2 router:

Pin characteristics of 5 up V35 lines

6. View routing information for each router

View R1 routing information:

View R2 routing information:

Work expansion

The above experiment is realized by using PPP protocol, and different methods are used to realize the experiment, such as non-authentication, PAP single authentication, PAP double authentication, CHAP authentication and so on.

(1) Topology diagram

(2) based on PPP non-authentication method

The main configuration of the R1 router:

The main configuration of the R2 router:

View R1 information:

View R2 information:

(3) PAP one-way authentication

The main configuration of the R1 router:

The main configuration of the R2 router:

(4) PAP two-way authentication

R1 router configuration:

(4) PAP two-way authentication

R1 router configuration:

R2 router configuration:

Think about the question:

Can 1:CHAP also achieve one-way and two-way authentication?

One-way authentication only configures this parameter by the active caller, and authentication is initiated by the callee when one-way. Two-way verification

There is no need to configure both sides. In the end, links are established.

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