ZyXEL Communications IES-1248-51A, Руководство пользователя

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Chapter 28 DHCP Relay
IES-1248-51V User’s Guide
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and optional information about the slot and port on which the DHCP request was
received.
The following table shows the format of the private Agent Circuit ID sub-option.
The (binary) “1” in the first field identifies this as an Agent Circuit ID sub-option.
The length N gives the total number of octets in the Agent Information Field. If
the configuration request was received on a DSL port, a 1-byte Slot No field
specifies the ingress slot number, and a 1-byte Port No field specifies the ingress
port number (both in hexadecimal format). The next field is 2 bytes and displays
the DHCP request packet’s VLAN ID. The last field (A) can range from 1 to 24
bytes (including a one-byte termination character) and is optional information
(that you specify) about this relay agent.
The Agent Information field that the device adds also contains an “Agent Remote-
ID sub-option” of information that you specify.
The following table shows the format of the private Agent Remote ID sub-option.
The “2” in the first field identifies this as an Agent Remote ID sub-option. The
length N gives the total number of octets in the Agent Information Field. Next, the
extra information field (A in the table) contains from 0 to 23 bytes of optional
information (that you specify) with no spaces and no termination character (if you
do not specify any information, this field contains no data). Next, there is a space
and the letters “eth” followed by another space. Then there is the slot number and
port number (in plain text format) upon which the DHCP client request was
received. This is followed by a colon (:), the VLAN ID (VID) number, a period (.)
and the MAC address (in hexadecimal format).
28.2.2 TR-101 Format
The Agent Information field that the IES-1248-51V adds contains an “Agent
Circuit-ID sub-option” that includes the system name or IP address, slot ID, port
number, VPI, and VCI on which the TCP/IP configuration request was received.
The following figure shows the format of the TR-101 Agent Circuit ID sub-option.
The 1 in the first field identifies this as an Agent Circuit ID sub-option. The next
field specifies the length of the field. The hostname field displays the system
name, if it has been configured, the extra information field (A) if the hostname
was not configured, or the IP address in dotted decimal notation (w.x.y.z), if
neither the system name nor the extra information field was been configured. In
either case, the hostname is truncated to 23 characters, and trailing spaces are
Table 57 DHCP Relay Agent Circuit ID Sub-option Format: Private
1 N Slot No Port No VLAN ID A
Table 58 DHCP Relay Agent Remote ID Sub-option Format: Private
2 N A “ eth
“
Slot No. / Port No. : VLAN ID . MAC