One 、 Network type ：

Point to point

BMA： Broadcast multiple access – In a MA There are also broadcasts in the network （ flooding ） Mechanism

NBMA： Non broadcast multiple access — In a MA In the network , No flooding mechanism

MA： Multiple access   In a network segment , There is no limit to the number of nodes

Two 、 Encapsulation technology of data link layer

【1】 Point to point – In a network segment , The number of nodes is physically and logically limited to 2 individual ;

      Two layer packaging technology based on point-to-point work , There is no layer 2 unicast address , such as MAC Address

HDLC Cisco Encapsulation technology used by default ; Each manufacturer owns this technology

PPP   Not Cisco The default encapsulation technology used by the serial interface ; Public technology     stay HDLC On this basis, some functions are further added ;

PAP Pass user name and password in clear text

CHAP   Ciphertext

GRE Generic routing encapsulation --   A simple VPN technology --   It belongs to the type of point-to-point network

VPN Virtual private network --- Let the two networks communicate directly through the intermediate network , Logically, a new point-to-point direct link is established between the two networks ;

BMA – Broadcast multiple access   In a MA There are also broadcasts in the network segment 、 Flooding function ;

Ethernet   Shared network    

In a physical link, a large number of frequency radio waves are used to transmit data at the same time , Play the role of bandwidth superposition ;

NBMA   Non broadcast multiple access    --- Frame relay /MGRE

Between multiple networks, you need to pass VPN To build a whole network , If you use point-to-point GRE;tunnel And the number of network segments will increase exponentially , The routing table will become larger , All nodes are required to be fixed public IP Address ;

MGRE Can solve these problems ：

MGRE— Multipoint GRE  -- Also known as DSVPN The automatic intelligent VPN= MGRE+IPSEC

ordinary GRE Is a point-to-point network type ; If multiple nodes are used as normal GRE Connect , A large number of network segments and routing information will be configured , And all nodes are fixed IP Address ;

The experiment is as follows

  The experiment purpose

 1.R2 by ISP, Can only be configured on it IP Address
2.R1-R2 Between for HDLC encapsulation
3.R2-R3 Between for ppp encapsulation ,pap authentication ,r2 Main certifier
4.R2-R4 Between for PPP encapsulation ,chap authentication ,R2 Main certifier
5.R1、R4、R3 structure MGRE Environmental Science , only R1IP Fixed address
6. Intranet usage RIP Get route , all pc Can access each other , And accessible R2 The loopback of .

Investigate knowledge points ：

hdlc encapsulation  ppp encapsulation pap authentication chap authentication   To configure MGRE Environmental Science rip dynamic

Experimental thinking

1 Divide network segments , configure port ip, Loopback routing   Public network critical route configuration default route

2. To configure hdlc ppp encapsulation Conduct network segment pap chap authentication

3 build MGRE Environmental Science

4 Conduct rip Dynamic routing protocol configuration

Experimental process

Partial routing ip as follows

r1 And r2 route ip

 2. To configure hdlc ppp encapsulation Conduct network segment pap chap authentication

 3 build MGRE Environmental Science

、

The build result test is as follows （ Because of the use of rip, So turn off horizontal segmentation ） 

[r1-Tunnel0/0/0]undo rip split-horizon   

 4 Conduct rip Dynamic routing protocol configuration

Route result acquisition

r1 as follows

r2 Without deleting the horizontal partition, it is divided as follows

  Delete the horizontal division as follows

  equipment ping through

Access loopback