Network type

Network type —— Divide according to the protocol used in the data link layer

MA（ Multipoint access network ）

BMA—— Broadcast multipoint access network

NBMA—— Non broadcast multipoint access network

P2P（ Point to point network ）

Ethernet protocol —— Need to use MAC Address distinguishes and identifies different host devices .

Use MAC Address for data addressing , Mainly because the layer-2 network using Ethernet components can include multiple interfaces , Each Ethernet interface can carry out layer-2 communication by means of interactive Ethernet frames .——BMA

When a network can only contain two devices , Then such a network does not need to be used MAC Address address , Such a net

Collaterals are called P2P The Internet .

T1——1.544Mbps

E1——2.048Mbps

Ethernet —— Frequency division （ On the same transmission medium, radio waves of different frequency bands can be sent at the same time , And they don't interfere with each other , Realize the parallel transmission of data .）

HDLC—— Advanced data link control protocol

The standard HDIC—— from ISO Those that meet industrial standards issued by the organization HDLC edition

Non standard HDLC—— Major manufacturers based on Standards HDLC The agreement has been improved , Incompatible with other protocols （ By default , The encapsulation protocol used in the serial network of Cisco device components is HDLC, Huawei uses PPP agreement , It is more compatible ）

[r1]display interface Serial 4/0/0—— View the layer 2 features of the interface

[r1-Serial4/0/0]link-protocol hdlc—— Modify the protocol type of layer 2

PPP—— Point to point agreement

1. Strong compatibility , There is a unified version , And as long as it supports full duplex serial lines , You can use PPP Protocol encapsulation .

2.PPP The protocol has strong portability ——PPPPoE

3. Support authentication and authorization

ppp The protocol and TCP The agreement is similar to , Before transmitting data , Need to establish PPP conversation .

1. Link establishment phase ——LCP establish

2. Authentication phase —— optional

3. Network layer protocol negotiation stage ——NCP negotiation ——NCP An agreement is a collection of agreements ——IPCP agreement

ppp The agreement has a series of membership agreements

LCP—— Link control protocol （ One ）

NCP—— Network control protocol （ a pile ）——IPCP agreement