No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search

Reminder

To have a better experience, please upgrade your IE browser.

upgrade

Feature Description - LAN Access and MAN Access 01

NE05E and NE08E V300R003C10SPC500

This is NE05E and NE08E V300R003C10SPC500 Feature Description - LAN Access and MAN Access
Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
DHCPv6 Messages

DHCPv6 Messages

Similar to DHCP messages, DHCPv6 messages are also carried over UDP, with UDP port 546 assigned to DHCPv6 clients and UDP port 547 assigned to DHCPv6 relay agents and servers.

IPv6 does not support broadcast packets, and therefore DHCPv6 clients use multicast IPv6 packets for communication. DHCPv6 clients use the multicast address FF02::1:2 to communicate with DHCPv6 relay agents and servers. DHCPv6 relay agents and servers use the multicast address FF05::1:3 to communicate with each other.

DHCPv6 messages share an identical fixed format header and a variable format area for options.

Introduction

  • DHCPv6 message types

    Unlike DHCP messages for which the message type is specified in the Message Type option, DHCPv6 messages use the msg-type field in the header to identify the message type. Table 5-1 lists the DHCPv6 message types.

    Table 5-1 DHCPv6 message types

    Type

    Code

    Description

    SOLICIT

    1

    A client sends a Solicit message to locate servers.

    ADVERTISE

    2

    A server sends an Advertise message in response to a Solicit message received from a client to indicate that it is available for DHCPv6 services.

    REQUEST

    3

    A client sends a Request message to request IP addresses and other configuration parameters from a server.

    CONFIRM

    4

    A client sends a Confirm message to any available server to determine whether the IP addresses it was assigned are still applicable to the link to which the client is connected.

    RENEW

    5

    A client sends a Renew message to the server that provided the client's addresses and other configuration parameters to extend the lease of the IP addresses assigned to the client and to update other configuration parameters.

    REBIND

    6

    A client sends a Rebind message to any available server to extend the lease of the IP addresses assigned to the client and to update other configuration parameters. This message is sent if a client does not receive a response to a Renew message.

    REPLY

    7

    A server sends a Reply message in the following scenarios:
    • A server sends a Reply message containing assigned IP addresses and configuration parameters in response to a Solicit, Request, Renew, or Rebind message received from a client.
    • A server sends a Reply message containing configuration parameters in response to an Information-request message.
    • A server sends a Reply message in response to a Confirm message, confirming or denying that the IP addresses assigned to the client are applicable to the link to which the client is connected.
    • A server sends a Reply message to acknowledge receipt of a Release or Decline message.

    RELEASE

    8

    A client sends a Release message to the server that assigned addresses to the client to indicate that the client will no longer use one or more of the assigned addresses.

    DECLINE

    9

    A client sends a Decline message to a server to indicate that the client has determined that one or more addresses assigned by the server are already in use on the link to which the client is connected.

    RECONFIGURE

    10

    A server sends a Reconfigure message to a client to inform the client that the server has new or updated configuration parameters.

    INFORMATION-REQUEST

    11

    A client sends an Information-Request message to a server to request configuration parameters without any IP addresses.

    RELAY-FORW

    12

    A relay agent sends a Relay-Forward message to relay messages to servers.

    RELAY-REPLY

    13

    A server sends a Relay-Reply message to a relay agent containing a message that the relay agent delivers to a client.

  • DHCPv6 message format

    DHCPv6 messages share an identical fixed format header and a variable format area for options, which are different from those of DHCP messages. DHCPv6 messages transmitted between clients and servers and between relay agents and servers have different header formats.
    • DHCPv6 client/server message format

      Figure 5-2 shows the DHCPv6 client/server message format.

      Figure 5-2 DHCPv6 client/server message format

      Table 5-2 describes fields in a DHCPv6 client/server message.
      Table 5-2 DHCPv6 client/server message fields

      Field

      Length

      Description

      Value

      msg-type

      1 byte

      DHCP message type

      The value ranges from 1 to 11. The available message types are listed in Table 5-1.

      transaction-id

      3 bytes

      Transaction ID for this message exchange, indicating one exchange of DHCPv6 messages

      -

      options

      Variable

      Options carried in this message

      -
    • DHCPv6 relay agent/server message format

      Figure 5-3 shows the relay agent/server message format.

      Figure 5-3 DHCPv6 relay agent/server message format

      Only Relay-Forward and Relay-reply messages are exchanged between DHCPv6 relay agents and servers. Figure 5-4 lists the fields of a DHCPv6 relay agent/server message.
      Table 5-3 DHCPv6 relay agent/server message fields

      Field

      Length

      Usage 1

      Usage 2

      msg-type

      1 byte

      RELAY-FORW

      RELAY-REPL

      hop-count

      1 byte

      Number of relay agents that have relayed this message

      Copied from the Relay-Forward message

      link-address

      16 bytes

      An IPv6 global unicast or link-local address that will be used by the server to identify the link to which the client is connected

      Copied from the Relay-Forward message

      peer-address

      16 bytes

      IP address of the client or relay agent from which the message to be relayed was received

      Copied from the Relay-Forward message

      options

      Variable

      Must include the Relay Message option; may include other options added by the relay agent

      Must include the Relay Message option; may include other options

DHCPv6 Options

  • DHCPv6 options format

    Figure 5-4 shows the DHCPv6 options format.
    Figure 5-4 DHCPv6 options format

    Table 5-4 lists the sub-fields in the DHCPv6 options field
    Table 5-4 Sub-fields in the DHCPv6 options field

    Sub-field

    Length

    Description

    option-code

    2 bytes

    Options ID

    option-len

    2 bytes

    Length of the option-data field

    option-data

    Determined by the option-len value

    Data for the option

  • DHCPv6 relay options

    A Relay-Forward or Relay-Reply message must have a Relay Message option (Option 9) that carries a DHCPv6 message.

    DHCPv6 relay Interface-ID option (Option 18), Remote-ID option (Option 37) have the same functions as DHCP relay Option 82. These DHCPv6 options are added by DHCPv6 relay agents in Relay-Forward messages for DHCPv6 servers. Servers use these options to learn the location of DHCPv6 clients, implement client security and accounting, and make parameter assignment policies, allowing for more flexible address assignment.

    Table 5-5 lists the DHCPv6 relay options.

    Table 5-5 DHCPv6 relay options

    Option

    Options ID

    Description

    Relay Message

    9

    Carries a DHCPv6 message.

    Interface-ID

    18

    Identifies the interface on which the client message was received.

    Remote-ID

    37

    Carries additional information, such as the DHCP Unique Identifier (DUID), port identifier, and VLAN ID.

Translation
Download
Updated: 2019-01-14

Document ID: EDOC1100058932

Views: 7330

Downloads: 11

Average rating:
This Document Applies to these Products
Related Documents
Related Version
Share
Previous Next