Links between Routes for network protocol analysis

The usual encapsulation technology is the encapsulation of Ethernet, PPP and HDLC. Ethernet is often used for the connection between local area networks, and the latter two are commonly used for WAN encapsulation.

The Ethernet (Ethernet) frame format Ethernetⅱ is one of the most common Ethernet frame formats and is also the de facto standard for today's Ethernet.

The main feature of Ethernetⅱ is the protocol used by the type domain to identify packets encapsulated in a frame, and the Type field is a valid pointer through which the data link layer can host multiple upper layer (Network level) protocols. However, the disadvantage of Ethernetⅱ is that there are no fields that identify frame lengths. VLAN is a protocol to solve the broadcast problem and security of Ethernet, it adds VLAN header on the basis of Ethernet frame , divides the user into smaller workgroup with VLAN ID, restricts the mutual exchange between different working groups, and each workgroup is a virtual local area network. The benefit of a virtual local area network is that it can limit the broadcast range and be able to form virtual workgroups to dynamically manage the network. using VLAN technology can divide multiple network segments and effectively solve the problem of interfaces. Its technical advantage is that it can limit the broadcast on the network.

Point-to-Point protocol PPP is a kind of link layer protocol that provides network layer packets on a point-to-point link. It is a character-oriented protocol. The working process of PPP link consists of 4 stages: Link Establishment phase, link authentication phase, Network Layer Control Protocol stage and link termination phase. PPP Authentication configuration:

(i) Encapsulate PPP protocol.

Router (config-if) # encapsulation PPP

(b) record the peer-to-peer router name and password on this router.

Router (config) # username ...

Password ...

(c) Set the local router name and password.

Router (config) # hostname ...

Router (config) # enable secret ...

(d) Configure the authentication method.

Router (config-if) # PPP Authentication

(v) Send authentication information to the peer-to-peer router.

Router (config-if) # PPP pap sentusername ...

Password ...

HDLC is a point-to-point data Transfer Protocol with two types of frame structure, one ISO frame format and one Cisco frame format. Configuration of HDLC:

(i) Set up HDLC encapsulation.

Router (config-if) # encapsulation HDLC

(b) Set the DCE end line rate.

Router (config-if) # Clockrate Speed

The encapsulation of the WAN link and the encapsulation on the Ethernet are very different. Compared to the HDLC,PPP has more functions.

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Links between Routes for network protocol analysis