Implementing IPFIX

An IST Project http://www.ist-scampi.org/

Implementing IPFIX

Luca Deri <[email protected]>

NETikos S.p.A.


Implementation Overview

• This work evaluated the effort required to implement IPFIX starting from NetFlow v9 because:– NetFlow is the leading protocol for flow-based

measurements.– This is a reasonable scenario at least for the early

days of IPFIX.

• Implementing IPFIX basically means:– Provide support for vendor-specific (I.e. non IETF)

field types.– Add SCTP support.


Vendor-Specific Extensions

• Vendor-specific fields are defined using a PEN (IANA enterprise number) and a numeric field.

• As templates and flows are slightly different from IETF-defined fields this requires the implementation of additional logic inside the IPFIX applications.

• Suggestion: IETF should unify the template format using an unique format for both IETF and vendor-specific fields.


SCTP Support

• It is a shift from connection-less to connection-oriented protocols.

• Little coding is necessary for supporting the protocol ‘per-se’.

• Reduce template traffic: they are sent at the beginning or in case of reconnection.

• Major code changes the probe supports multiple collectors: it is necessary to resend the templates per-connection (i.e. only when it’s necessary).


SCTP Issues

• Flows are (often) acknowledged (almost) immediately increasing significantly the network traffic. This amplifies problems in some situations (e.g. in case of DoS attacks).

• SCTP is supported only on a few platforms and there are no plans to support it in Windows or network equipment. This could limit the usage of IPFIX at least in its early days.

• Unclear how reliable/robust is SCTP and how it behaves in production environments (network attacks?).

UDP SCTP

Packets 1Õ667 2Õ514 [+50%]

Bytes 2Õ509Õ542 2Õ595Õ952 [+3%]


IPFIX Evaluation

IPFIX Evaluation:– It’s basically a “standard” NetFlow (that’s both good and bad).

– Very little innovation after 10 years of flow-based measurement.

Major IPFIX limitations are:– No dynamic templates: static templates push people to define a “super-

template” that contains everything even if only a few fields are used.

– Ability to define flows but not flow headers.

– Still based on the concept of flow-packet even with SCTP.

– One-way protocol (probe->collector): no support for configuration, monitoring, and error reporting (e.g. via SNMP like sFlow does).

– Too tight to NetFlow: will IPFIX be able to grow and evolve without Cisco’s blessing?


IPFIX Feedback

• Written Internet Draft about IPFIX implementation experience.

• Implemented IPFIX support in both probe and collector (ntop).

• Availability: http://www.ntop.org/

Implementing IPFIX

Documents

Transcript of Implementing IPFIX