Packet Exported in IPFIX Format

Packets exported in IPFIX format and V9 format have similar structures except for the packet header and Field Specifier.

Header of a NetStream Packet Exported in IPFIX Format

Figure 1 shows the format of the header of a NetStream packet exported in IPFIX format. This header corresponds to the Header field in Figure 1. Table 1 describes the fields in the header.

Figure 1 Header of a NetStream packet exported in IPFIX format

**Table 1** Fields of a NetStream packet header in IPFIX format
Field	Description
Version Number	Version number of the format in which NetStream packets are exported.
Length	The packet length of the Header of a NetStream Packet Exported in IPFIX Format, including message header, in bytes.
Export Time	Indicates the UTC time when the flow record is sent from Exporter (total number of offset seconds from 00:00:00 on January 1, 1970 to the current time), in seconds.
Sequence Number	Sequence number of an exported packet. You can check whether a NetStream packet is dropped based on the flow sequence value. No serial number is added to the template and option template.
Observation Domain ID	Indicates the Observation Domain ID. It is a unique number to identify a flow sending from a router.

IPFIX Field Specifier

The IPFIX Field Specifier contains enterprise identifier information in addition to the V9-formatted content of the Field Type and Field Length fields. Figure 2 shows the format of an IPFIX Field Specifier. Table 2 describes the fields in an IPFIX Field Specifier.

Figure 2 Format of an IPFIX Field Specifier

**Table 2** Fields in an IPFIX Field Specifier
Field	Description
E	Enterprise bit, which is the first bit of an IPFIX Field Specifier. If the value is set to 0, the Information Element Identifier field identifies an Information Element in [IANA-IPFIX], and the 4-byte Enterprise Number field must not exist. If the value is set to 1, the Information Element Identifier field identifies an enterprise-specific Information Element, and the Enterprise Number field must exist.
Information Element Identifier	A numeric value that represents the Information Element.
Field Length	Length of the corresponding encoded Information Element, in bytes.
Enterprise Number	IANA enterprise number [IANA-PEN] of the authority that defines the Information Element Identifier in this template record.