Internet Draft B. Claise
Document: draft-claise-ipfix-eval-netflow-02.txt Cisco Systems
Expires: April 2003 October 2002
Evaluation Of NetFlow Version 9 Against IPFIX Requirements
<draft-claise-ipfix-eval-netflow-02.txt>
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Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
This document provides an evaluation of the applicability of the NetFlow
flow record export protocol version 9 as an IPFIX protocol. It compares
the properties and capabilities of the NetFlow flow record export protocol
version 9 to the IPFIX requirements [IPFIX-REQ].
Table of Contents
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1. Introduction...................................................3
2. Architectural Considerations...................................5
2.1 NetFlow Protocol Overview..................................5
2.2 General Applicability......................................6
2.2.1 Flow Definition........................................6
2.2.2 Observation Point......................................7
2.2.3 The Metering Process and the Flow Record...............7
2.2.4 The Exporting Process..................................7
2.2.5 The Collecting Process.................................7
2.3 Architectural Differences..................................8
3. Item Level Compliance Evaluation...............................8
3.1 Terminology (section 2)....................................9
3.1.1 IP Traffic Flow (2.1)..................................9
3.1.2 Observation Point (2.2)................................9
3.1.3 Metering Process (2.3).................................9
3.1.4 Flow Record (2.4).....................................10
3.1.5 Exporting Process (2.5)...............................10
3.1.6 Collecting Process (2.6)..............................10
3.2 Applications Requiring IP Flow Information Export (3).....10
3.3 Distinguishing Flows (4)..................................10
3.3.1 Interface (4.1).......................................10
3.3.2 IP Header Fields (4.2)................................11
3.3.3 Transport Header Fields (4.3).........................11
3.3.4 MPLS (4.4)............................................11
3.3.5 DiffServ Code Point (4.5).............................11
3.3.6 Header Compression and Encryption (4.6)...............11
3.4 Metering Process (5)......................................11
3.4.1 Reliability (5.1).....................................11
3.4.2 Sampling (5.2)........................................11
3.4.3 Overload Behavior (5.3)...............................12
3.4.4 Timestamps (5.4)......................................13
3.4.5 Time Synchronization (5.5)............................13
3.4.6 Flow Expiration (5.6).................................13
3.4.7 Multicast (5.7).......................................14
3.4.8 Packet Fragmentation (5.8)............................14
3.4.9 Ignore Port Copy (5.9)................................14
3.5 Data Export (6)...........................................14
3.5.1 Information Model (6.1)...............................14
3.5.2 Data Model (6.2)......................................15
3.5.3 Data Transfer (6.3)...................................16
3.5.3.1 Congestion Awareness (6.3.1)......................16
3.5.3.2 Reliability (6.3.2)...............................16
3.5.3.3 Security (6.3.3)..................................16
3.5.4 Push and Pull Mode Reporting (6.4)....................16
3.5.5 Regular Reporting Interval (6.5)......................16
3.5.6 Notification on Specific Events (6.6).................17
3.5.7 Anonymization (6.6)...................................17
3.6 Configuration (7).........................................17
3.6.1 Configuration of the Metering Process (7.1)...........17
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3.6.2 Configuration of the Exporting Process (7.2)..........17
3.7 General Requirements Compliance (8).......................18
3.7.1 Openness (8.1)........................................18
3.7.2 Number of Exporting Processes (8.2)...................18
3.7.3 Several Collecting Processes (8.3)....................18
3.8 Compliance Summary........................................18
4. Security Considerations.......................................22
5. References....................................................22
6. Acknowledgments...............................................23
1. Introduction
This document provides an evaluation of the applicability of the NetFlow
flow record export protocol version 9 as an IPFIX protocol. First, the
general NetFlow architecture is introduced and its application to the
communication between an IPFIX exporting process and an IPFIX collecting
process is discussed in Section 2. Section 3 discusses in detail, to which
degree requirements stated in [IPFIX-REQ] are met.
This document uses the terminology defined in [IPFIX-REQ].
Note that the generic term NetFlow refers to multiple different notions:
the metering process, the exporting process and the export protocol, as
defined in the IPFIX terminology section of [IPFIX-REQ].
Even if the metering process and exporting process form a single NetFlow
process on the Cisco Systems devices, this document will sometimes refer
to NetFlow metering process and NetFlow exporting process for the sake of
clarity. But the export protocol will always be referred to as the NetFlow
flow record export protocol version 9.
- How and where is it documented?
All documentation related to NetFlow can be found at:
http://www.cisco.com/go/netflow
More specifically, the ôNetFlow Services Solutions Guideö covers a NetFlow
overview, the basic and advanced concepts, the explanation of the
different versions along with the data types exported, some configuration
examples, etc. For reference, see:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/intsolns/netflsol/nfwhite
.htm
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The new flexible and extensible NetFlow flow record export version 9 is
described in the IETF draft "Cisco Systems NetFlow Services Export Version
9" [NETFLOW9], as well as in the following document:
http://www.cisco.com/warp/public/cc/pd/iosw/prodlit/ntfo_wp.htm
Note that [NETFLOW9-1] is about to be submitted to the rfc-editor.
- Are there concrete plans for standardizing it?
The way to standardize NetFlow is via the IETF IPFIX Working Group.
In parallel, Cisco Systems intention is to produce an Information RFC out
of [NETFLOW9].
- Is standardization already in progress?
No other standardization than the participation to the IETF IPFIX Working
Group is currently taking place.
- Is it proprietary to a certain company?
NetFlow is a proprietary protocol from Cisco Systems.
- Does it include any technology protected by patents?
NetFlow is protected by the following patent:
United States Patent 6,243,667 Kerr, et al. June 5, 2001
Abstract:
The invention provides a method and system for switching in networks
responsive to message flow patterns. A message "flow" is defined to
comprise a set of packets to be transmitted between a particular source
and a particular destination. When routers in a network identify a new
message flow, they determine the proper processing for packets in that
message flow and cache that information for that message flow. Thereafter,
when routers in a network identify a packet which is part of that message
flow, they process that packet according to the proper processing for
packets in that message flow. The proper processing may include a
determination of a destination port for routing those packets and a
determination of whether access control permits routing those packets to
their indicated destination.
Nevertheless, Cisco Systems has no intention to use this patent to prevent
other vendors to implement a NetFlow-like solution.
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An Intellectual Property Right message has been sent to the IETF rfc-
editor team to post a similar message at http://www.ietf.org/ipr.html
- Is it already implemented?
The NetFlow flow record export protocol version 9 protocol is currently at
the stage of the Early Field Test, while NetFlow flow record export
versions 1, 5, 7 and 8 have been implemented for years now.
- Is it already in commercial use?
Some Cisco Systems partners are currently developing NetFlow Collectors
(the correct term is ôcollecting processö according to [IPFIX-REQ]) able
to receive NetFlow version 9 flow records.
While many different companies or organizations have already implemented
NetFlow Collectors for the previous NetFlow flow record export protocols
versions. Ex: Concord Communications, Hewlett Packard, Narus, Xacct,
Portal, Apogee Networks, Infovista, etc. to name just a few.
- Is it available from more than one source?
As the inventor of NetFlow, Cisco Systems is the only company implementing
this new version 9 on its devices. But, if we speak of the previous
NetFlow flow record export protocol versions, then the majority of our
competitors implemented those versions.
- Is it already widely used?
The new NetFlow flow record export protocol version 9 is in Early Field
Test right now, while the previous NetFlow flow record export versions
have been implemented by our competitors. As a consequence, NetFlow is
widely used through out the industry.
2. Architectural Considerations
This section introduces the architecture of the NetFlow and suggests a way
of applying it to the communication between an IPFIX exporting process and
an IPFIX collecting process.
2.1 NetFlow Protocol Overview
This section discusses the most recent evolution of the NetFlow flow
record export protocol, which is known as Version 9. The distinguishing
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feature of the NetFlow Version 9 format compared to the previous versions,
is that it is template based. Template is a collection of fields along
with the description of their structure and semantics.
This approach gives the following advantages:
- The template mechanism being flexible, allows the export of the
required fields alone from the IP Flows to the collecting process.
This helps to reduce the exported flow data volume, and generates
possible memory savings at the metering process and collecting
process. Sending the required information only, reduces the network
load too.
- Using the template mechanism, new fields can be added to NetFlow
export records without changing the structure of export record
format. With the previous NetFlow flow record export versions,
adding a new field in the flow record implied a new version of the
export protocol format and a new version of the collecting process
that supports the parsing of this new export protocol format.
- Templates which are sent to the collecting process contains the
structural information about the exported Flow Records fields. So,
even if the collecting process does not understand the semantics of
new fields, it can still interpret the Flow Record.
- Even if the NetFlow flow record export protocol version 9 has been
created with a IP flow record background in mind, note that the
Information Model can be extended with any data types and could
potentially serve any reporting purposes. E.g. the NetFlow metering
process configuration.
2.2 General Applicability
2.2.1 Flow Definition
A NetFlow flow is identified as a unidirectional stream of packets between
a given source and destinationùboth defined by a network-layer IP address
and transport-layer source and destination port numbers. Typically in case
of ingress NetFlow, a flow is identified as the combination of the
following seven key fields: source IP address, destination IP address,
source port number, destination port number, layer 3 protocol type, ToS
byte, input logical interface (ifIndex). In case of egress NetFlow, a flow
is identified as the combination of the following seven key fields: source
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IP address, destination IP address, source port number, destination port
number, layer 3 protocol type, ToS byte, output logical interface
(ifIndex).
These seven key fields define a unique flow. If a new observed packet
contains a different set of these seven key fields, then this packet will
create a new flow. Note that a flow contains other accounting fields (such
as the number of packets, number of bytes, the BGP AS, etc).
2.2.2 Observation Point
NetFlow can be enabled per interface (physical/logical) per linecard or
per system. However implementation restrictions apply on a platform basis.
2.2.3 The Metering Process and the Flow Record
NetFlow operates by creating a NetFlow cache that contains the information
for all active flows. A flow record is maintained within the NetFlow cache
for all active flows. Each flow record in the NetFlow cache contains key
fields that can be later used for exporting to a collecting process.
2.2.4 The Exporting Process
The NetFlow enabled platform checks the NetFlow cache on regular basis and
expires the flows if no more traffic of these flows is observed. Once
expired, the flow records are directly exported to the collecting process.
To achieve efficiency in terms of processing at the Exporter while
handling high volume of export, the NetFlow export packet is encapsulated
into UDP [UDP] datagrams for export to the collecting process.
Nevertheless NetFlow flow record export protocol version 9 has been
designed to be transport protocol independent. Hence, it can also operate
over congestion aware protocols like TCP [TCP] or SCTP [SCTP].
Note that the UDP port to which the NetFlow flow records are exported is
configurable.
2.2.5 The Collecting Process
The NetFlow Collector (the collecting process) provides the data
collection from multiple export devices exporting NetFlow flow
records. It will process and store the flow records. Some extra
actions on these flow records could be executed on the collecting
process but per [IPFIX-REQ], these actions are out of the scope of
the IPFIX work.
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2.3 Architectural Differences
+----------------+ +----------------+
|[*Application 1]| ..|[*Application n]|
+--------+-------+ +-------+--------+
^ ^
~ ~
+~~~~~~~~~~+~~~~~~~~+
!
v
+----------------------+ +------------------+
|Device(i) | | Collector(j) |
|[Obsv Point(s)] |--------------->| [*Application(s)]|
|[Metering Process(es)]| +---->| |
|[Export Process] | | +------------------+
+----------------------+ .
.... .
+----------------------+ |
|Device(m) | |
|[Obsv Point(s)] |----------+
|[Metering Process(es)]|
|[Export Process] |
+----------------------+
Except the terminology difference again described below, there is no
difference between the NetFlow and IPFIX architecture.
Note that the generic term NetFlow refers to multiple different notions:
the metering process, the exporting process and the export protocol, as
defined in the IPFIX terminology section of [IPFIX-REQ].
Even if the metering process and exporting process form a single NetFlow
process on the Cisco Systems devices, this document will sometimes refer
to NetFlow metering process and NetFlow exporting process for the sake of
clarity. But the export protocol will always be referred to as the NetFlow
flow record export protocol version 9.
3. Item Level Compliance Evaluation
This section evaluates the compliance of the NetFlow protocol with the
IPFIX requirements item by item. Requirements are addressed by their
section numbers and item numbers in [IPFIX-REQ]. For each requirement
it is explained to what degree protocol NetFlow flow export version 9
meets the requirement and how this is achieved. The degree of compliancy
is explicitly stated using five grades:
-T Total compliance: The requirement is met completely by the
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protocol specification without any extensions required.
-E Extension required for total compliance: The protocol is
prepared to be extended and it is possible to extend it in a
way that it meets the requirement. This grade is only
applicable to protocols that are explicitly open to externally
defined extensions, such as SNMP is extended by MIB modules or
DIAMETER is extended by application modules. It is not
applicable to protocols, where the protocol specification itself
needs to be extended in order to comply with the requirement.
-P Partial compliance: The requirement is met partially by the
protocol specification.
-U Upcoming compliance: The requirement is not met or met
partially by the protocol specification, but there is a
concrete plan for an upcoming version of the protocol.
-F Failed compliance: The requirement is not met by the protocol
specification.
3.1 Terminology (section 2)
3.1.1 IP Traffic Flow (2.1)
Total Compliance of NetFlow Flow definition with the IPFIX IP
Traffic Flow definition.
3.1.2 Observation Point (2.2)
Total Compliance of NetFlow Observation Point definition with the
IPFIX Observation Point definition. NetFlow is enabled by interface
or per subinterface. NetFlow can be enable on multiple interfaces
at the same time, e.g. all interfaces belonging to one line card, or
all the interfaces from the device. On specific device, NetFlow is
enabled for the entire platform.
3.1.3 Metering Process (2.3)
Total Compliance of NetFlow with the IPFIX Metering Process
definition, for all aspects: packet header capturing, timestamping,
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sampling, classifying, and maintaining flow records.
3.1.4 Flow Record (2.4)
Total Compliance of NetFlow Flow Record definition with the IPFIX
Flow Record definition.
3.1.5 Exporting Process (2.5)
Total Compliance of NetFlow Exporting Process with the IPFIX
Exporting Process definition. The NetFlow Exporting Process may send
the flow records to 2 different collecting processes.
3.1.6 Collecting Process (2.6)
Total Compliance of NetFlow Collector with the IPFIX collecting
process definition.
3.2 Applications Requiring IP Flow Information Export (3)
Total Compliance of NetFlow regarding the different applications
described in [IPFIX-REQ] which require IP flow information export,
i.e. Usage-based Accounting, Traffic Profiling, Traffic Engineering,
Attack/Intrusion Detection and QoS Monitoring. Actually, the
Information Model associated with NetFlow flow record export version
9 [NETFLOW9] contains all the data types needed to satisfy the
requirements of the different applications described in the section
ôApplications Requiring IP Flow Information Exportö from [IPFIX-
REQ].
3.3 Distinguishing Flows (4)
3.3.1 Interface (4.1)
Total Compliance of the interface as a flow distinguisher.
In case of ingress NetFlow, a flow is identified, amongst other
fields, by the input logical interface (ifIndex). In case of egress
NetFlow, a flow is identified, amongst other fields by output
logical interface (ifIndex). All flow records will report both the
input and output ifIndexes.
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3.3.2 IP Header Fields (4.2)
source IP address (MUST): Total Compliance
destination IP address (MUST): Total Compliance
protocol type (TCP,UDP,ICMP,...) (MUST): Total Compliance
IP version number (SHOULD): Upcoming Compliance
3.3.3 Transport Header Fields (4.3)
Total Compliance of the port numbers of the transport header as a
flow distinguisher.
3.3.4 MPLS (4.4)
Total Compliance of the MPLS label as a flow distinguisher, if the
observation point is located at a device supporting Multiprotocol
Label Switching.
3.3.5 DiffServ Code Point (4.5)
Total Compliance, as NetFlow distinguishes flow by the TOS byte
(DiffServ Code Point).
3.3.6 Header Compression and Encryption (4.6)
Total Compliance.
3.4 Metering Process (5)
3.4.1 Reliability (5.1)
Total Compliance. The metering process is reliable.
3.4.2 Sampling (5.2)
ôThe metering process MAY support packet sampling.ö, as defined in
[IPFIX-REQ]ô. Total Compliance. NetFlow supports packet sampling.
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ôIf sampling is supported the sampling configuration MUST be well
defined. The sampling configuration includes the sampling method and
all its parameters.ö, as defined in [IPFIX-REQ]. Total Compliance.
See the Options Template from [NETFLOW9]: a template that describes
the format of the Flow measurement parameters (like the sampling
algorithm, sampling interval) done at the metering process.
ôIf the sampling configuration is changed during operation, the new
sampling configuration with its parameters MUST be indicated to all
collecting processes receiving the affected flow records. Changing
the sampling configuration includes: start sampling, stop sampling,
change sampling method, and change sampling parameter.ô, as defined
in [IPFIX-REQ]ô.
Start sampling: Total Compliance
Stop sampling: Extension Required
Change sampling method: Total Compliance
Change sampling parameter: Total Compliance
3.4.3 Overload Behavior (5.3)
ôIn case of an overload, for example lack of memory or processing
power, the metering process MAY change its behavior in order to cope
with the lack of resources.ö, as defined in [IPFIX-REQ].
Total Compliance.
ôFor some flows, the change of behavior might have an impact on the
data that would be stored in the associated flow records after the
change, for example if the packet classification is changed or the
sampling rate. These flows MUST be considered as terminated and the
associated flow records MUST be exported separately from new ones
generated after the behavior change. ö, as defined in [IPFIX-REQ].
ôThe terminated flow records and new ones generated after the
behavior change MUST NOT be merged by the metering process.ö, as
defined in [IPFIX-REQ].
ôThe collecting process MUST be able to distinguish the affected
flow records generated before and after the change of behavior.ö, as
defined in [IPFIX-REQ].
Let me address the 3 requirements above together.
If the metering process configuration is changed, then Total
Compliance. A new Template ID for the new template configuration
will be generated and the collecting process will be able to
distinguish the new flow records from the old ones.
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In case of memory, flow records or CPU overload, Total Compliance.
Overload of memory: not possible because NetFlow allocates the
entire cache memory at initialization.
Overload of flow records: not possible because in case the NetFlow
cache becomes full, the flow records will be expired with a smaller
timeout! This change in the exporting process behavior doesnÆt need
to be reported: anyway the flow records contain the absolute
timestamps.
Overload of CPU: the throughput will be lowered in order for NetFlow
to account all traffic.
In case of cpu overload, in order to avoid a lower throughput, some
new automatic actions (like new template with sampling NetFlow
instead of full NetFlow or new template with higher sampling rate
etcà) could be implemented without much effort.
Note that in both examples above, a new Template ID for the new
template configuration will be generated and the collecting process
will be able to distinguish the new flow records from the old ones.
3.4.4 Timestamps (5.4)
Total Compliance.
3.4.5 Time Synchronization (5.5)
Total Compliance.
The export packet header contains the UTC time of the export packet
generation. This header also contains the router sysUpTime at the
time of the export packet generation. The UTC time the router booted
can therefore be deduced. The flow records contain the flow start
and flow end sysUpTime, so that the NetFlow collector can deduce the
flow start and flow end UTC time.
3.4.6 Flow Expiration (5.6)
Total Compliance of the NetFlow flow expiration mechanism with the
IPFIX requirements.
The routing device checks the NetFlow cache once per second and expires
the flow in the following instances:
1. Transport is completed (TCP FIN or RST).
2. The flow cache has become full.
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3. The inactive timer has expired after 15 seconds of traffic
inactivity. This inactive timer is configurable, with a minimum
value of 0 for a immediate expiration.
4. The active timer has expired after 30 minutes of traffic activity.
This active timer is configurable.
3.4.7 Multicast (5.7)
Total Compliance of the multicast support with the IPFIX
requirements.
3.4.8 Packet Fragmentation (5.8)
ôThe metering process MAY keep state of IP packet fragmentation in
order to map fragments that do not contain sufficient header
information correctly to flows.ö, as defined in [IPFIX-REQ].
Extension Required for Total Compliance.
3.4.9 Ignore Port Copy (5.9)
Total Compliance. The metering process ignores packets that are
generated by a port copy function acting at the device where the
observation point of a flow is located.
3.5 Data Export (6)
3.5.1 Information Model (6.1)
ôThe exporting process MUST be able to report the following
attributes for each metered flowö, as defined in [IPFIX-REQ]:
1. IP version number: Total Compliance
2. source IP address: Total Compliance
3. destination IP address: Total Compliance
4. IP protocol type (TCP,UDP,ICMP,...) : Total Compliance
5. source TCP/UDP port number: Total Compliance
6. destination TCP/UDP port number: Total Compliance
7. packet counter: Total Compliance
8. byte counter: Total Compliance
9. type of service octet (in case of IPv4), traffic class octet (in
case of IPv6): Total Compliance
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10. in case of IPv6, Flow Label: Total Compliance
11. if MPLS is supported at the observation point: the top MPLS
label or the corresponding forwarding equivalence class (FEC,
[RFC3031]) bound to that label. Total Compliance for the top MPLS
label and the corresponding FEC.
12. timestamp of the first packet of the flow: Total Compliance
13. timestamp of the last packet of the flow: Total Compliance
14. if sampling is used, sampling configuration: Total Compliance
15. unique identifier of the observation point: Total Compliance
(the ifIndex)
16. unique identifier of the exporting process: Total Compliance
(the IP address and the Observation Domain Identifier)
ôThe exporting process SHOULD be able to report the following
attributes for each metered flowö, as defined in [IPFIX-REQ]:
17. input interface (ifIndex): Total Compliance
18. output interface (ifIndex): Total Compliance
19. multicast replication factor. Total Compliance
ôThe exporting process MAY be able to report the following
attributes for each metered flowö, as defined in [IPFIX-REQ]:
20. Time To Live: Extension required for Total Compliance
21. IP header flags: Extension required for Total Compliance
22. TCP header flags: Total Compliance
23. dropped packet counter at the observation point: Extension
required for Total Compliance
24. fragmented packet counter: Extension Required for Total
Compliance
25. Next hop IP address: Total Compliance
In addition, the exporting process MAY be able to report attributes
related to inter-autonomous system routing of a flow, for example by
reporting BGP Autonomous System numbers. Total Compliance
3.5.2 Data Model (6.2)
ôThe data model MUST be extensibleö, as defined in [IPFIX-REQ].
Total Compliance. While all data types discussed in [NETFLOW9]
concern the IP flows and the metering process, nothing prevents
NetFlow version 9 to export whatever type of data. For example, a
MIB variable or the output of a ôshow commandö on the router.
NetFlow version 9 is extensible to whatever data type.
ôThe data model used for exporting flow information MUST be flexible
concerning the flow attributes contained in flow recordsö, as
defined in [IPFIX-REQ].
Total Compliance.
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ôThe Data Model SHOULD be independent of the underlying transport
protocol, i.e. the data transferö, as defined in [IPFIX-REQ].
Total Compliance.
3.5.3 Data Transfer (6.3)
3.5.3.1 Congestion Awareness (6.3.1)
ôFor the data transfer, a congestion aware protocol MUST be
supportedö, as defined in [IPFIX-REQ].
Upcoming Compliance with SCTP.
Note that the flow record export protocol version 9 is independent
of the underlying transport protocol.
3.5.3.2 Reliability (6.3.2)
Total Compliance. A sequence ID exists per export packet so that the
collecting process would know if it misses export packets or if
packets reordering occurred in the network.
3.5.3.3 Security (6.3.3)
Extension Required for total Compliance for confidentiality,
integrity and authenticity for the flow record export protocol
version 9 itself.
But note that exporting the NetFlow flow records from the exporting
process to the metering process over an IPSEC [IPSEC] tunnel would
fulfill all the confidentiality, integrity and authenticity
requirements.
3.5.4 Push and Pull Mode Reporting (6.4)
NetFlow is a Push Mode Reporting mechanism and doesnÆt support the
Pull Mode.
3.5.5 Regular Reporting Interval (6.5)
Total Compliance. For long aging flows, the exporting process
exports the flow records on regular basis, in order to:
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1. report the flow records periodic accounting information
to the collecting process
2. avoid counter wrapping
This activity timeout is configurable
3.5.6 Notification on Specific Events (6.6)
Failed Compliance.
3.5.7 Anonymization (6.6)
ôThe exporting process MAY be capable of anonymizing source and
destination IP addresses in flow data before exporting them.ö
Total Compliance.
ôThe exporting process MAY support anonymization of port numbers and
other fields.ö
Total Compliance.
Router-based aggregations of flow records can be enabled in order to
aggregate the flow records and as a consequence, anonymize some of
the flow records data types. Typical example: the source and
destination IP addresses will be hidden. Instead the network
prefixes will be reported.
Another solution would simply be not to report the data types we
want to anonymize. Typical example: the network prefixes are
reported instead of the IP addresses but the network prefixes are
meaningful. As a consequence, the template would export none of the
IP addresses and the prefixes.
3.6 Configuration (7)
3.6.1 Configuration of the Metering Process (7.1)
Total Compliance.
3.6.2 Configuration of the Exporting Process (7.2)
Total Compliance.
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3.7 General Requirements Compliance (8)
3.7.1 Openness (8.1)
Total Compliance.
3.7.2 Number of Exporting Processes (8.2)
ôData collection from hundreds of different exporting processes MUST
be supported.ö, as defined in [IPFIX-REQ].
Total Compliance.
ôThe collecting process MUST be able to distinguish several hundred
exporting processes by their identifiers.ö, as defined in [IPFIX-
REQ].
Total Compliance, the identifier being the IP address of the
exporting process and the Observation Domain identifier.
The Observation Domain is defined as:
The set of observation points which is the largest aggregatable set
of flow information at the metering process is termed as an
Observation Domain. The Observation Domain presents itself a unique
identifier to the collecting process for identifying the export
packets generated by it. One or more Observation Domains can
interface with the same export process. Example: The Observation
Domain could be a router line-card, composed of several interfaces
with each interface being an observation point.
3.7.3 Several Collecting Processes (8.3)
Total Compliance. The exporting process is able to export flow
information to two different collecting processes and the flow
records can be identified thanks to a sequence ID, the Observation
Domain and the Exporter IP address.
3.8 Compliance Summary
M: MUST
S: SHOULD
May: MAY
----------------------------------------------.
B: IPFIX Requirement Status |
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----------------------------------------. |
A: NetFlow Version 9 Compliance | |
----------------------------------. | |
| | |
| Sect. | Requirement | | |
|-------+-------------------------+-----+-----|
| 2. | Terminology | T | |
|-------+-------------------------+-----+-----|
| 3. | Applicatitons | T | |
|-------+-------------------------+-----+-----|
| 4. | DISTINGUISHING FLOWS |
|-------+-------------------------+-----+-----|
| 4.1 | Interfaces | T | M |
|-------+-------------------------+-----+-----|
| 4.2 | Source IP address | T | M |
|-------+-------------------------+-----+-----|
| 4.2 | Destination IP address | T | M |
|-------+-------------------------+-----+-----|
| 4.2 | Protocol Type | T | M |
|-------+-------------------------+-----+-----|
| 4.2 | IP version | T | S |
|-------+-------------------------+-----+-----|
| 4.3 | Transport Header Fields | T | M |
|-------+-------------------------+-----+-----|
| 4.4 | MPLS | T | M |
|-------+-------------------------+-----+-----|
| 4.5 | DiffServ Code Point | T | M |
|-------+-------------------------+-----+-----|
| 4.6 | Header Compres/Encrypt. | T | M |
|-------+-------------------------+-----+-----|
| 5. | METERING PROCESS |
|-------+-------------------------+-----+-----|
| 5.1 | Reliability | T | M |
|-------+-------------------------+-----+-----|
| 5.2 | Sampling | T | May |
|-------+-------------------------+-----+-----|
| 5.3 | Overload Behavior | T | May |
|-------+-------------------------+-----+-----|
| 5.4 | TimeStamps | T | M |
|-------+-------------------------+-----+-----|
| 5.5 | Time Synchronization | T | M |
|-------+-------------------------+-----+-----|
| 5.6 | Flow Expiration | T | M |
|-------+-------------------------+-----+-----|
| 5.7 | Multicast Flows | T | S |
|-------+-------------------------+-----+-----|
| 5.8 | Packet Fragmentation | E | May |
|-------+-------------------------+-----+-----|
| 5.9 | Ignore Port Copy | T | May |
|-------+-------------------------+-----+-----|
| 6. | DATA EXPORT |
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|-------+-------------------------+-----+-----|
| 6.1. | INFORMATION MODEL |
|-------+-------------------------+-----+-----|
| 6.1. | IP Version | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | src IP address | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | dst IP address | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | protocol type | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | src TCP/UDP port | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | dst TCP/UPD port | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | Packet counter | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | Byte counter | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | TOS/Traffic Class | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | Flow Label | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | MPLS label/FEC | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | Timestamps for | T | M |
| | first packet | | |
|-------+-------------------------+-----+-----|
| 6.1. | Timestamps for | T | M |
| | last packet | | |
|-------+-------------------------+-----+-----|
| 6.1. | Sampling configuration | T | M |
|-------+-------------------------+-----+-----|
| 6.1. | observation point | T | M |
| | identifier | | |
|-------+-------------------------+-----+-----|
| 6.1. | export process | T | M |
| | identifier | | |
|-------+-------------------------+-----+-----|
| 6.1. | Input Interface | T | S |
|-------+-------------------------+-----+-----|
| 6.1. | OutputInterface | T | S |
|-------+-------------------------+-----+-----|
| 6.1. | Multicast Replication | T | S |
|-------+-------------------------+-----+-----|
| 6.1. | Time to Live | E | May |
|-------+-------------------------+-----+-----|
| 6.1. | IP Header Flags | E | May |
|-------+-------------------------+-----+-----|
| 6.1. | TCP Header Flags | T | May |
|-------+-------------------------+-----+-----|
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| 6.1. | Dropped Packet Counter | E | May |
|-------+-------------------------+-----+-----|
| 6.1. | Fragmented Pkt Counter | E | May |
|-------+-------------------------+-----+-----|
| 6.1. | IP Next Hop | T | May |
|-------+-------------------------+-----+-----|
| 6.1. | BGP AS Info | T | May |
|-------+-------------------------+-----+-----|
| 6.2. | DATA MODEL |
|-------+-------------------------+-----+-----|
| 6.2. | Flexibility | T | M |
|-------+-------------------------+-----+-----|
| 6.2. | Extensibility | T | M |
|-------+-------------------------+-----+-----|
| 6.2. | Transport Independant | T | S |
|-------+-------------------------+-----+-----|
| 6.3. | DATA TRANSFER |
|-------+-------------------------+-----+-----|
| 6.3.1.| Congestion aware | U | M |
|-------+-------------------------+-----+-----|
| 6.3.2.| Reliability | T | M |
|-------+-------------------------+-----+-----|
| 6.3.3.| Confidentiality | E | S |
|-------+-------------------------+-----+-----|
| 6.3.4.| Integrity | E | M |
|-------+-------------------------+-----+-----|
| 6.3.5.| Authenticity | E | M |
|-------+-------------------------+-----+-----|
| 6.4. | Push mode | T | M |
|-------+-------------------------+-----+-----|
| 6.4. | Pull mode | F | May |
|-------+-------------------------+-----+-----|
| 6.5 | Regular Interval | T | S |
|-------+-------------------------+-----+-----|
| 6.6. | Notifications | F | May |
|-------+-------------------------+-----+-----|
| 6.7. | Anonymization | T | May |
|-------+-------------------------+-----+-----|
| 7. | CONFIGURATION |
|-------+-------------------------+-----+-----|
| 7. | Config Metering Process | T | M |
|-------+-------------------------+-----+-----|
| 7. | Config Exporting Process| T | S |
|-------+-------------------------+-----+-----|
| 7. | Config Flow | T | S |
| | Specifications | | |
|-------+-------------------------+-----+-----|
| 7. | Config Flow Timeouts | T | S |
|-------+-------------------------+-----+-----|
| 7. | Config Sampling | T | May |
|-------+-------------------------+-----+-----|
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| 7. | Config Report | T | S |
| | Data Format | | |
|-------+-------------------------+-----+-----|
| 7. | Config Notifications | F | May |
|-------+-------------------------+-----+-----|
| 7. | Config Anonymization | T | May |
|-------+-------------------------+-----+-----|
| 8. | GENERAL REQUIREMENTS |
|-------+-------------------------+-----+-----|
| 8.1. | Openness | T | S |
|-------+-------------------------+-----+-----|
| 8.2. | Scalability: | | |
| | data collection | T | M |
| | from hundreds of | | |
| | measurement devices | | |
|-------+-------------------------+-----+-----|
| 8.3. | Several Collectors | T | May |
.-------+-------------------------+-----+-----.
Note that some of the requirements in the table above are not
necessarily applicable for the strict selection of the candidate
protocol. Up to the evaluation team not to consider those.
4. Security Considerations
Security considerations for the IPFIX protocol are covered by the
comparison against the specific Security requirements in the IPFIX
requirements document [IPFIX-REQ] where they are specifically
addressed by sections 6.3.3 and 10.
The NetFlow flow record export protocol could be run on the top of
IPSEC [IPSEC] to assure security.
5. References
[IPFIX-REQ] J. Quittek et al., "Requirements for IP Flow Information
Export", draft-ietf-ipfix-reqs-06.txt, work in progress,
July 2002.
[NETFLOW9] B. Claise et al., "Cisco Systems NetFlow Services Export
Version 9", draft-bclaise-netflow-9-00.txt, work in progress,
June 2002.
[NETFLOW9-1] B. Claise et al., "Cisco Systems NetFlow Services Export
Version 9", draft-bclaise-netflow-9-01.txt, work in progress,
About to be submitted.
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[UDP] J. Postel, "User Datagram Protocol", RFC 768, August
1980
[TCP] "TRANSMISSION CONTROL PROTOCOL DARPA INTERNET PROGRAM
PROTOCOL SPECIFICATION", RFC 793, September 1981
[SCTP] R. Stewart et al, "Stream Control Transmission Protocol",
RFC 2960, October 2000
[IPSEC] Kent, S., "Security Architecture for the Internet
Protocol", RFC 2401, Nov. 1998,
6. Acknowledgments
I would like to thank Ganesh Sadasivan, Vamsidhar Valluri, Martin
Djernaes and Pritam Shah from Cisco Systems for the valuable
technical feedback on this Internet Draft.
Author's Address
Benoit Claise
Cisco Systems
De Kleetlaan 6a b1
1831 Diegem
Belgium
Phone: +32 2 704 5622
Email: bclaise@cisco.com
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copyrights defined in the Internet Standards process must be
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