Principle of the computer network of the three follow-up (Internet protocol)

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       a)     The IPv6 protocol

            i.          The prefix is 000000 compatible.

               ii.                IPv6 traffic class: 8bit datagram class or priority.

, For the source node labeled IPv6 to IPv6 the IPv4 transition technology mainly has three programs: the tunnel technology, dual stack technology and address protocol conversion technology (NAT-PT dual protocol stack: refers to the complete transition to the IPv6 and IPv6 packages or IPv6 and IPv6 and IPv6 tunnel technology: in the tunnel entrance to the IPv6 network., Router IPv6, IPv4 address. In the tunnel exit and the IPv6 and IPv6 and IPv4 consists of two parts: network address translation protocol and protocol conversion.

              iv.          Agreement

                i.          QoS (1 to provide users with the definition and classification of high quality QoS.

Resource reservation.

(some performance indicators: the availability of 2, error rate, response time, throughput, packet loss rate, connection setup time, fault detection and correction time.

       )The main QoS) /), differentiated service (DiffServ), traffic engineering, QoS: the basic idea is that a service to gain a certain quality of service, must be in before requesting network to network traffic for its reserved resources needed. (RSVP: According to predetermined rules to classify the data flow, will have the same QoS: use to each packet a fixed marker, new technology for high-speed, efficient transmission of packet forwarding in hardware in open communication network.

b)     With UDP

The characteristics of 1.TCP protocol: connection oriented, reliable, full duplex, byte stream oriented, end-to-end service.

               ii.          TCP connection establishment and release mechanism

TCP connection release mechanism: semi closed and closed two stages.

              iv.          The parameter TCP involved: segment round-trip time RTT, the weighted deviation timeout retransmission time average values of RTO RTTD congestion control strategy

Available resources

TCP random early detection RED

Wireless TCP

Programs can be roughly divided into three categories:

(1)    The TCP transmitter to send different errors in the transmission process of processing, so that the sender can cause the effective treatment of a variety of mobile environment, data packet dropout.

(2)    On the base station to the TCP data link layer scheme at the source and destination


UDP does not need to establish a connection before sending data.

(2)    Congestion cannot be UDP user data only 8 networks appear to reduce the sending rate of source host.

The application layer protocol of UDP

                i.          )

To resolve the host name in DNS to the corresponding IP is an online distributed database system, client server mode.

(1) DNS naming methods: hierarchical tree structure.

(2) : Address type, IN

      record-type: Data record type.

(3) The root name servers: keep all top-level domain name server IP top-level domain name server: management of registered in this top-level domain name server on all the two level domain name.

c)     The local name server

(4) The client to resolve host domain name on the DNS user data will be sent to the local name server. The local name server queries against it, if the search is successful, will result in the DNS message is returned to the requesting party.

Iterative query:

(5) The DNS e-mail protocol

1.     Including the user agent, the mail server, the message transfer agent and mail protocol

2.     Transmission protocol

Command and three types of response information.

b)     As long as the user from the POP server will delete the mail.

                                           ii.          IMAP

Server messages in a mailbox will be kept.

c)     Agreement


              iii.          )

Between the client and the server needs to build two TCP remote login protocol (Telnet and HTTP using a uniform resource locator (URL) on the document, an identification method Webpage and other resources of the address.

2.     Provided the key characteristics of a web client: stored in hard disk, is associated with a user, persistent storage in a certain period of time, the data can be shared across browsers, need to be serialized, the sending server -: to provide information for the current user session.

The Session client data transmission.

c)     The key characteristic of Cache:: stored in the server, and the session, may be dropped at any time according to the server memory resources condition, not be serialized, no server Dynamic Host Configuration Protocol (DHCPDHCP function: centralized management and communication protocol is automatically assigned IP address.

2.     The DHCP message type

4.     The DHCP server to open UDP port 67, snoop requests.

The DHCP server sends a DHCPOFFER message.

The DHCP server returned DHCPACK, contains the assigned IP address.

The DHCP server if agree, then send confirmation message DHCPACK.

The DHCP server sends the message DHCPRELEASE release

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Posted by Glendon at December 25, 2013 - 6:55 PM