以太网协议号

IP:     0x0800
ARP:    0x0806
PPPOE:  0x8863 0x8864

IP协议号
    ICMP:   1
    TCP:    6
    UDP:    17
    GRE:    47
    ESP:    50
    AH:     51
端口号
    FTP:    20 21
    SSH:    22
    Telnet: 23
    SMTP:   25
    TACACS+:    49
    HTTP:   80
    HTTPS:  443
    IKE:    500(udp)
    Radius: 1645 1646 1812 1813



    route (路由器),switch(交换机) ,media(介质,无线,网线,)

    ap access point (接入点)
    controller
    asa

impact of user application

• batch application ftp
• interactive applications ssh

• real-time applications video

  bit frame packet segment PDU

Applicati Transport Internet Link