draft-ietf-i2nsf-applicability-08.txt   draft-ietf-i2nsf-applicability-09.txt 
I2NSF Working Group J. Jeong I2NSF Working Group J. Jeong
Internet-Draft Sungkyunkwan University Internet-Draft Sungkyunkwan University
Intended status: Informational S. Hyun Intended status: Informational S. Hyun
Expires: June 28, 2019 Chosun University Expires: September 12, 2019 Chosun University
T. Ahn T. Ahn
Korea Telecom Korea Telecom
S. Hares S. Hares
Huawei Huawei
D. Lopez D. Lopez
Telefonica I+D Telefonica I+D
December 25, 2018 March 11, 2019
Applicability of Interfaces to Network Security Functions to Network- Applicability of Interfaces to Network Security Functions to Network-
Based Security Services Based Security Services
draft-ietf-i2nsf-applicability-08 draft-ietf-i2nsf-applicability-09
Abstract Abstract
This document describes the applicability of Interface to Network This document describes the applicability of Interface to Network
Security Functions (I2NSF) to network-based security services in Security Functions (I2NSF) to network-based security services in
Network Functions Virtualization (NFV) environments, such as Network Functions Virtualization (NFV) environments, such as
firewall, deep packet inspection, or attack mitigation engines. firewall, deep packet inspection, or attack mitigation engines.
Status of This Memo Status of This Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 28, 2019. This Internet-Draft will expire on September 12, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. I2NSF Framework . . . . . . . . . . . . . . . . . . . . . . . 5 3. I2NSF Framework . . . . . . . . . . . . . . . . . . . . . . . 5
4. Time-dependent Web Access Control Service . . . . . . . . . . 6 4. Time-dependent Web Access Control Service . . . . . . . . . . 6
5. I2NSF Framework with SFC . . . . . . . . . . . . . . . . . . 8 5. I2NSF Framework with SFC . . . . . . . . . . . . . . . . . . 8
6. I2NSF Framework with SDN . . . . . . . . . . . . . . . . . . 9 6. I2NSF Framework with SDN . . . . . . . . . . . . . . . . . . 10
6.1. Firewall: Centralized Firewall System . . . . . . . . . . 12 6.1. Firewall: Centralized Firewall System . . . . . . . . . . 13
6.2. Deep Packet Inspection: Centralized VoIP/VoLTE Security 6.2. Deep Packet Inspection: Centralized VoIP/VoLTE Security
System . . . . . . . . . . . . . . . . . . . . . . . . . 13 System . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.3. Attack Mitigation: Centralized DDoS-attack Mitigation 6.3. Attack Mitigation: Centralized DDoS-attack Mitigation
System . . . . . . . . . . . . . . . . . . . . . . . . . 15 System . . . . . . . . . . . . . . . . . . . . . . . . . 16
7. I2NSF Framework with NFV . . . . . . . . . . . . . . . . . . 18 7. I2NSF Framework with NFV . . . . . . . . . . . . . . . . . . 19
8. Security Considerations . . . . . . . . . . . . . . . . . . . 19 8. Security Considerations . . . . . . . . . . . . . . . . . . . 20
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 20 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
11.1. Normative References . . . . . . . . . . . . . . . . . . 20 11.1. Normative References . . . . . . . . . . . . . . . . . . 21
11.2. Informative References . . . . . . . . . . . . . . . . . 21 11.2. Informative References . . . . . . . . . . . . . . . . . 22
Appendix A. Changes from draft-ietf-i2nsf-applicability-07 . . . 24 Appendix A. Changes from draft-ietf-i2nsf-applicability-08 . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction 1. Introduction
Interface to Network Security Functions (I2NSF) defines a framework Interface to Network Security Functions (I2NSF) defines a framework
and interfaces for interacting with Network Security Functions and interfaces for interacting with Network Security Functions
(NSFs). Note that Network Security Function (NSF) is defined as a (NSFs). Note that Network Security Function (NSF) is defined as a
funcional block for a security service within an I2NSF framework that funcional block for a security service within an I2NSF framework that
has well-defined I2NSF NSF-facing interface and other external has well-defined I2NSF NSF-facing interface and other external
interfaces and well-defined functional behavior [NFV-Terminology]. interfaces and well-defined functional behavior [NFV-Terminology].
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The implementation of I2NSF in these scenarios has allowed us to The implementation of I2NSF in these scenarios has allowed us to
verify the applicability and effectiveness of the I2NSF framework for verify the applicability and effectiveness of the I2NSF framework for
a variety of use cases. a variety of use cases.
2. Terminology 2. Terminology
This document uses the terminology described in [RFC7665], [RFC7149], This document uses the terminology described in [RFC7665], [RFC7149],
[ITU-T.Y.3300], [ONF-OpenFlow], [ONF-SDN-Architecture], [ITU-T.Y.3300], [ONF-OpenFlow], [ONF-SDN-Architecture],
[ITU-T.X.1252], [ITU-T.X.800], [NFV-Terminology], [RFC8329], [ITU-T.X.1252], [ITU-T.X.800], [NFV-Terminology], [RFC8329],
[i2nsf-terminology], [consumer-facing-inf-im], [i2nsf-terminology], [consumer-facing-inf-dm], [i2nsf-nsf-cap-im],
[consumer-facing-inf-dm], [i2nsf-nsf-cap-im], [nsf-facing-inf-dm], [nsf-facing-inf-dm], [registration-inf-dm], and
[registration-inf-dm], and [nsf-triggered-steering]. In addition, [nsf-triggered-steering]. In addition, the following terms are
the following terms are defined below: defined below:
o Software-Defined Networking (SDN): A set of techniques that o Software-Defined Networking (SDN): A set of techniques that
enables to directly program, orchestrate, control, and manage enables to directly program, orchestrate, control, and manage
network resources, which facilitates the design, delivery and network resources, which facilitates the design, delivery and
operation of network services in a dynamic and scalable manner operation of network services in a dynamic and scalable manner
[ITU-T.Y.3300]. [ITU-T.Y.3300].
o Network Function: A funcional block within a network o Network Function: A funcional block within a network
infrastructure that has well-defined external interfaces and well- infrastructure that has well-defined external interfaces and well-
defined functional behavior [NFV-Terminology]. defined functional behavior [NFV-Terminology].
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Figure 1: I2NSF Framework Figure 1: I2NSF Framework
3. I2NSF Framework 3. I2NSF Framework
This section summarizes the I2NSF framework as defined in [RFC8329]. This section summarizes the I2NSF framework as defined in [RFC8329].
As shown in Figure 1, an I2NSF User can use security functions by As shown in Figure 1, an I2NSF User can use security functions by
delivering high-level security policies, which specify security delivering high-level security policies, which specify security
requirements that the I2NSF user wants to enforce, to the Security requirements that the I2NSF user wants to enforce, to the Security
Controller via the Consumer-Facing Interface Controller via the Consumer-Facing Interface
[consumer-facing-inf-im][consumer-facing-inf-dm]. [consumer-facing-inf-dm].
The Security Controller receives and analyzes the high-level security The Security Controller receives and analyzes the high-level security
policies from an I2NSF User, and identifies what types of security policies from an I2NSF User, and identifies what types of security
capabilities are required to meet these high-level security policies. capabilities are required to meet these high-level security policies.
The Security Controller then identifies NSFs that have the required The Security Controller then identifies NSFs that have the required
security capabilities, and generates low-level security policies for security capabilities, and generates low-level security policies for
each of the NSFs so that the high-level security policies are each of the NSFs so that the high-level security policies are
eventually enforced by those NSFs [policy-translation]. Finally, the eventually enforced by those NSFs [policy-translation]. Finally, the
Security Controller sends the generated low-level security policies Security Controller sends the generated low-level security policies
to the NSFs [i2nsf-nsf-cap-im][nsf-facing-inf-dm]. to the NSFs [i2nsf-nsf-cap-im][nsf-facing-inf-dm].
The Security Controller requests NSFs to perform low-level security The Security Controller requests NSFs to perform low-level security
services via the NSF-Facing Interface. As shown in Figure 1, with a services via the NSF-Facing Interface. As shown in Figure 1, with a
Developer's Management System, developers (or vendors) inform the Developer's Management System (DMS), developers (or vendors) inform
Security Controller of the capabilities of the NSFs through the I2NSF the Security Controller of the capabilities of the NSFs through the
Registration Interface [registration-inf-dm] for registering (or I2NSF Registration Interface [registration-inf-dm] for registering
deregistering) the corresponding NSFs. Note that an inside attacker (or deregistering) the corresponding NSFs. Note that an inside
at the Development Management System can seriously weaken the I2NSF attacker at the DMS can seriously weaken the I2NSF system's security.
system's security. For the detection and prevention of inside To deal with this type of threat, the role of the DMS should be
attacks, the Security Controller needs to monitor the activity of all restricted to providing an I2NSF system with the software package/
the Development Management Systems as well as the NSFs through the image for NSF execution, and the DMS should never be able to access
I2NSF NSF monitoring functionality [nsf-monitoring-dm]. NSFs in online/activated status for the I2NSF system's security. On
the other hand, an access to running (online) NSFs should be allowed
only to the Security Controller, not the DMS. Also, the Security
Controller can detect and prevent inside attacks by monitoring the
activity of all the DMSs as well as the NSFs through the I2NSF NSF
monitoring functionality [nsf-monitoring-dm].
The Consumer-Facing Interface between an I2NSF User and the Security The Consumer-Facing Interface between an I2NSF User and the Security
Controller can be implemented using, for example, RESTCONF [RFC8040]. Controller can be implemented using, for example, RESTCONF [RFC8040].
Data models specified by YANG [RFC6020] describe high-level security Data models specified by YANG [RFC6020] describe high-level security
policies to be specified by an I2NSF User. The data model defined in policies to be specified by an I2NSF User. The data model defined in
[consumer-facing-inf-dm] can be used for the I2NSF Consumer-Facing [consumer-facing-inf-dm] can be used for the I2NSF Consumer-Facing
Interface. Interface.
The NSF-Facing Interface between the Security Controller and NSFs can The NSF-Facing Interface between the Security Controller and NSFs can
be implemented using NETCONF [RFC6241]. YANG data models describe be implemented using NETCONF [RFC6241]. YANG data models describe
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The following sections describe different security service scenarios The following sections describe different security service scenarios
illustrating the applicability of the I2NSF framework. illustrating the applicability of the I2NSF framework.
4. Time-dependent Web Access Control Service 4. Time-dependent Web Access Control Service
This service scenario assumes that an enterprise network This service scenario assumes that an enterprise network
administrator wants to control the staff members' access to a administrator wants to control the staff members' access to a
particular Internet service (e.g., Example.com) during business particular Internet service (e.g., Example.com) during business
hours. The following is an example high-level security policy rule hours. The following is an example high-level security policy rule
that the administrator requests: Block the staff members' access to for a web filter that the administrator requests: Block the staff
Example.com from 9 AM to 6 PM. The administrator sends this high- members' access to Example.com from 9 AM to 6 PM. Figure 2 is an
level security policy to the Security Controller. Refer to an XML example XML code for this web filter:
file for the high-level security policy of a time-based web-filter in
[consumer-facing-inf-dm], whose data model is defined by YANG, and <I2NSF>
which is delivered over RESTCONF. <name>block_website</name>
<cond>
<src>Staff_Member's_PC</src>
<dest>Example.com</dest>
<time-span-start>9:00AM</time-span-start>
<time-span-end>-6:00PM</time-span-end>
</cond>
<action>block<action>
</I2NSF>
Figure 2: An XML Example for Time-based Web-filter
The security policy name is "block_website" with the tag "name". The
filtering condition has the source group "Staff_Member's_PC" with the
tag "src", the destination website "Example.com" with the tag "dest",
the filtering start time is the time "9:00AM" with the tag " time-
span-start", and the filtering end time is the time "6:00PM" with the
tag "time-span-end". The action is to "block" the packets satisfying
the above condition, that is, to drop those packets.
After receiving the high-level security policy, the Security After receiving the high-level security policy, the Security
Controller identifies required security capabilities, e.g., IP Controller identifies required security capabilities, e.g., IP
address and port number inspection capabilities and URL inspection address and port number inspection capabilities and URL inspection
capability. In this scenario, it is assumed that the IP address and capability. In this scenario, it is assumed that the IP address and
port number inspection capabilities are required to check whether a port number inspection capabilities are required to check whether a
received packet is an HTTP packet from a staff member. The URL received packet is an HTTP packet from a staff member. The URL
inspection capability is required to check whether the target URL of inspection capability is required to check whether the target URL of
a received packet is in the Example.com domain or not. a received packet is in the Example.com domain or not.
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HTTP packet from the staff member. HTTP packet from the staff member.
3. The firewall triggers the web filter to further inspect the 3. The firewall triggers the web filter to further inspect the
packet, and the packet is forwarded from the firewall to the web packet, and the packet is forwarded from the firewall to the web
filter. SFC technology can be utilized to support such packet filter. SFC technology can be utilized to support such packet
forwarding in the I2NSF framework [nsf-triggered-steering]. forwarding in the I2NSF framework [nsf-triggered-steering].
4. The web filter checks the target URL field of the received 4. The web filter checks the target URL field of the received
packet, and realizes the packet is toward Example.com. The web packet, and realizes the packet is toward Example.com. The web
filter then checks that the current time is in business hours. filter then checks that the current time is in business hours.
If so, the web filter drops the packet, and consequently the If so, the web filter drops the packet, and consequently the
staff member's access to Example.com during business hours is staff member's access to Example.com during business hours is
blocked. blocked.
5. I2NSF Framework with SFC
In the I2NSF architecture, an NSF can trigger an advanced security
action (e.g., DPI or DDoS attack mitigation) on a packet based on the
result of its own security inspection of the packet. For example, a
firewall triggers further inspection of a suspicious packet with DPI.
For this advanced security action to be fulfilled, the suspicious
packet should be forwarded from the current NSF to the successor NSF.
SFC [RFC7665] is a technology that enables this advanced security
action by steering a packet with multiple service functions (e.g.,
NSFs), and this technology can be utilized by the I2NSF architecture
to support the advanced security action.
+------------+ +------------+
| I2NSF User | | I2NSF User |
+------------+ +------------+
^ ^
| Consumer-Facing Interface | Consumer-Facing Interface
v v
+-------------------+ Registration +-----------------------+ +-------------------+ Registration +-----------------------+
|Security Controller|<-------------------->|Developer's Mgmt System| |Security Controller|<-------------------->|Developer's Mgmt System|
+-------------------+ Interface +-----------------------+ +-------------------+ Interface +-----------------------+
^ ^ ^ ^
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| +-----+ | | | (DPI) | | +-----+ | | | (DPI) |
+-----------------+ | +--------------+ +-----------------+ | +--------------+
| . | .
| . | .
| . | .
| +-----------------------+ | +-----------------------+
------>| NSF-n | ------>| NSF-n |
|(DDoS-Attack Mitigator)| |(DDoS-Attack Mitigator)|
+-----------------------+ +-----------------------+
Figure 2: An I2NSF Framework with SFC Figure 3: An I2NSF Framework with SFC
5. I2NSF Framework with SFC
In the I2NSF architecture, an NSF can trigger an advanced security
action (e.g., DPI or DDoS attack mitigation) on a packet based on the
result of its own security inspection of the packet. For example, a
firewall triggers further inspection of a suspicious packet with DPI.
For this advanced security action to be fulfilled, the suspicious
packet should be forwarded from the current NSF to the successor NSF.
SFC [RFC7665] is a technology that enables this advanced security
action by steering a packet with multiple service functions (e.g.,
NSFs), and this technology can be utilized by the I2NSF architecture
to support the advanced security action.
Figure 2 shows an I2NSF framework with the support of SFC. As shown Figure 3 shows an I2NSF framework with the support of SFC. As shown
in the figure, SFC generally requires classifiers and service in the figure, SFC generally requires classifiers and service
function forwarders (SFFs); classifiers are responsible for function forwarders (SFFs); classifiers are responsible for
determining which service function path (SFP) (i.e., an ordered determining which service function path (SFP) (i.e., an ordered
sequence of service functions) a given packet should pass through, sequence of service functions) a given packet should pass through,
according to pre-configured classification rules, and SFFs perform according to pre-configured classification rules, and SFFs perform
forwarding the given packet to the next service function (e.g., NSF) forwarding the given packet to the next service function (e.g., NSF)
on the SFP of the packet by referring to their forwarding tables. In on the SFP of the packet by referring to their forwarding tables. In
the I2NSF architecture with SFC, the Security Controller can take the I2NSF architecture with SFC, the Security Controller can take
responsibilities of generating classification rules for classifiers responsibilities of generating classification rules for classifiers
and forwarding tables for SFFs. By analyzing high-level security and forwarding tables for SFFs. By analyzing high-level security
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This section describes an I2NSF framework with SDN for I2NSF This section describes an I2NSF framework with SDN for I2NSF
applicability and use cases, such as firewall, deep packet applicability and use cases, such as firewall, deep packet
inspection, and DDoS-attack mitigation functions. SDN enables some inspection, and DDoS-attack mitigation functions. SDN enables some
packet filtering rules to be enforced in network forwarding elements packet filtering rules to be enforced in network forwarding elements
(e.g., switch) by controlling their packet forwarding rules. By (e.g., switch) by controlling their packet forwarding rules. By
taking advantage of this capability of SDN, it is possible to taking advantage of this capability of SDN, it is possible to
optimize the process of security service enforcement in the I2NSF optimize the process of security service enforcement in the I2NSF
system. system.
Figure 4 shows an I2NSF framework [RFC8329] with SDN networks to
support network-based security services. In this system, the
enforcement of security policy rules is divided into the SDN
forwarding elements (e.g., switch running as either a hardware middle
box or a software virtual switch) and NSFs (e.g., firewall running in
a form of a virtual network function [ETSI-NFV]). Especially, SDN
forwarding elements enforce simple packet filtering rules that can be
translated into their packet forwarding rules, whereas NSFs enforce
NSF-related security rules requiring the security capabilities of the
NSFs. For this purpose, the Security Controller instructs the SDN
Controller via NSF-Facing Interface so that SDN forwarding elements
can perform the required security services with flow tables under the
supervision of the SDN Controller.
+------------+ +------------+
| I2NSF User | | I2NSF User |
+------------+ +------------+
^ ^
| Consumer-Facing Interface | Consumer-Facing Interface
v v
+-------------------+ Registration +-----------------------+ +-------------------+ Registration +-----------------------+
|Security Controller|<-------------------->|Developer's Mgmt System| |Security Controller|<-------------------->|Developer's Mgmt System|
+-------------------+ Interface +-----------------------+ +-------------------+ Interface +-----------------------+
^ ^ ^ ^
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| +----------------+ | | +----------------+ |
| ^ | | ^ |
| | SDN Southbound Interface | | | SDN Southbound Interface |
| v | | v |
| +--------+ +------------+ +--------+ +--------+ | | +--------+ +------------+ +--------+ +--------+ |
| |Switch-1|-| Switch-2 |-|Switch-3|.......|Switch-m| | | |Switch-1|-| Switch-2 |-|Switch-3|.......|Switch-m| |
| | | |(Classifier)| | (SFF) | | | | | | | |(Classifier)| | (SFF) | | | |
| +--------+ +------------+ +--------+ +--------+ | | +--------+ +------------+ +--------+ +--------+ |
+-------------------------------------------------------------------+ +-------------------------------------------------------------------+
Figure 3: An I2NSF Framework with SDN Network Figure 4: An I2NSF Framework with SDN Network
Figure 3 shows an I2NSF framework [RFC8329] with SDN networks to
support network-based security services. In this system, the
enforcement of security policy rules is divided into the SDN
forwarding elements (e.g., switch running as either a hardware middle
box or a software virtual switch) and NSFs (e.g., firewall running in
a form of a virtual network function [ETSI-NFV]). Especially, SDN
forwarding elements enforce simple packet filtering rules that can be
translated into their packet forwarding rules, whereas NSFs enforce
NSF-related security rules requiring the security capabilities of the
NSFs. For this purpose, the Security Controller instructs the SDN
Controller via NSF-Facing Interface so that SDN forwarding elements
can perform the required security services with flow tables under the
supervision of the SDN Controller.
As an example, let us consider two different types of security rules: As an example, let us consider two different types of security rules:
Rule A is a simple packet filtering rule that checks only the IP Rule A is a simple packet filtering rule that checks only the IP
address and port number of a given packet, whereas rule B is a time- address and port number of a given packet, whereas rule B is a time-
consuming packet inspection rule for analyzing whether an attached consuming packet inspection rule for analyzing whether an attached
file being transmitted over a flow of packets contains malware. Rule file being transmitted over a flow of packets contains malware. Rule
A can be translated into packet forwarding rules of SDN forwarding A can be translated into packet forwarding rules of SDN forwarding
elements and thus be enforced by these elements. In contrast, rule B elements and thus be enforced by these elements. In contrast, rule B
cannot be enforced by forwarding elements, but it has to be enforced cannot be enforced by forwarding elements, but it has to be enforced
by NSFs with anti-malware capability. Specifically, a flow of by NSFs with anti-malware capability. Specifically, a flow of
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elements and which should be enforced by NSFs. If some of the given elements and which should be enforced by NSFs. If some of the given
rules requires security capabilities that can be provided by SDN rules requires security capabilities that can be provided by SDN
forwarding elements, then the Security Controller instructs the SDN forwarding elements, then the Security Controller instructs the SDN
Controller via NSF-Facing Interface so that SDN forwarding elements Controller via NSF-Facing Interface so that SDN forwarding elements
can enforce those security policy rules with flow tables under the can enforce those security policy rules with flow tables under the
supervision of the SDN Controller. Or if some rules require security supervision of the SDN Controller. Or if some rules require security
capabilities that cannot be provided by SDN forwarding elements but capabilities that cannot be provided by SDN forwarding elements but
by NSFs, then the Security Controller instructs relevant NSFs to by NSFs, then the Security Controller instructs relevant NSFs to
enforce those rules. enforce those rules.
The distinction between software-based SDN forwarding elements and
NSFs, which can both run as virtual network functions, may be
necessary for some management purposes in this system. For this, we
can take advantage of the NFV MANO where there is a subsystem that
maintains the descriptions of the capabilities each VNF can offer
[ETSI-NFV-MANO]. This subsystem can determine whether a given
software element (VNF instance) is an NSF or a virtualized SDN
switch. For example, if a VNF instance has anti-malware capability
according to the description of the VNF, it could be considered as an
NSF. A VNF onboarding system [VNF-ONBOARDING] can be used as such a
subsystem that maintains the descriptions of each VNF to tell whether
a VNF instance is for an NSF or for a virtualized SDN switch.
For the support of SFC in the I2NSF framework with SDN, as shown in For the support of SFC in the I2NSF framework with SDN, as shown in
Figure 3, network forwarding elements (e.g., switch) can play the Figure 4, network forwarding elements (e.g., switch) can play the
role of either SFC Classifier or SFF, which are explained in role of either SFC Classifier or SFF, which are explained in
Section 5. Classifier and SFF have an NSF-Facing Interface with Section 5. Classifier and SFF have an NSF-Facing Interface with
Security Controller. This interface is used to update security Security Controller. This interface is used to update security
service function chaining information for traffic flows. For service function chaining information for traffic flows. For
example, when it needs to update an SFP for a traffic flow in an SDN example, when it needs to update an SFP for a traffic flow in an SDN
network, as shown in Figure 3, SFF (denoted as Switch-3) asks network, as shown in Figure 4, SFF (denoted as Switch-3) asks
Security Controller to update the SFP for the traffic flow (needing Security Controller to update the SFP for the traffic flow (needing
another security service as an NSF) via NSF-Facing Interface. This another security service as an NSF) via NSF-Facing Interface. This
update lets Security Controller ask Classifier (denoted as Switch-2) update lets Security Controller ask Classifier (denoted as Switch-2)
to update the mapping between the traffic flow and SFP in Classifier to update the mapping between the traffic flow and SFP in Classifier
via NSF-Facing Interface. via NSF-Facing Interface.
The following subsections introduce three use cases for cloud-based The following subsections introduce three use cases for cloud-based
security services: (i) firewall system, (ii) deep packet inspection security services: (i) firewall system, (ii) deep packet inspection
system, and (iii) attack mitigation system. [RFC8192] system, and (iii) attack mitigation system. [RFC8192]
skipping to change at page 14, line 10 skipping to change at page 15, line 10
2. The Firewall analyzes the header fields of the packet, and 2. The Firewall analyzes the header fields of the packet, and
figures out that this is an unknown VoIP call flow's signal figures out that this is an unknown VoIP call flow's signal
packet (e.g., SIP packet) of a suspicious pattern. packet (e.g., SIP packet) of a suspicious pattern.
3. The Firewall triggers an appropriate security service function, 3. The Firewall triggers an appropriate security service function,
such as VoIP IPS, for detailed security analysis of the such as VoIP IPS, for detailed security analysis of the
suspicious signal packet. In order for this triggering of VoIP suspicious signal packet. In order for this triggering of VoIP
IPS to be served, the suspicious packet is sent to the Service IPS to be served, the suspicious packet is sent to the Service
Function Forwarder (SFF) that is usually a switch in an SDN Function Forwarder (SFF) that is usually a switch in an SDN
network, as shown in Figure 3. The SFF forwards the suspicious network, as shown in Figure 4. The SFF forwards the suspicious
signal packet to the VoIP IPS. signal packet to the VoIP IPS.
4. The VoIP IPS analyzes the headers and contents of the signal 4. The VoIP IPS analyzes the headers and contents of the signal
packet, such as calling number and session description headers packet, such as calling number and session description headers
[RFC4566]. [RFC4566].
5. If, for example, the VoIP IPS regards the packet as a spoofed 5. If, for example, the VoIP IPS regards the packet as a spoofed
packet by hackers or a scanning packet searching for VoIP/VoLTE packet by hackers or a scanning packet searching for VoIP/VoLTE
devices, it drops the packet. In addition, the VoIP IPS requests devices, it drops the packet. In addition, the VoIP IPS requests
the SDN Controller to block that packet and the subsequent the SDN Controller to block that packet and the subsequent
skipping to change at page 17, line 47 skipping to change at page 18, line 47
| | | Compute | | Storage | | Network | | | | | | | | Compute | | Storage | | Network | | | | |
| | | Hardware| | Hardware| | Hardware| | | | | | | | Hardware| | Hardware| | Hardware| | | | |
| | ----------- ----------- ----------- | | | | | | ----------- ----------- ----------- | | | |
| | Hardware Resources | | | NFV Management | | | Hardware Resources | | | NFV Management |
| +---------------------------------------+ | | and Orchestration | | +---------------------------------------+ | | and Orchestration |
| | | (MANO) | | | | (MANO) |
+-------------------------------------------+ +--------------------+ +-------------------------------------------+ +--------------------+
(a) = Registration Interface (a) = Registration Interface
(b) = Ve-Vnfm Interface (b) = Ve-Vnfm Interface
Figure 4: I2NSF Framework Implementation with respect to the NFV Figure 5: I2NSF Framework Implementation with respect to the NFV
Reference Architectural Framework Reference Architectural Framework
7. I2NSF Framework with NFV 7. I2NSF Framework with NFV
This section discusses the implementation of the I2NSF framework This section discusses the implementation of the I2NSF framework
using Network Functions Virtualization (NFV). using Network Functions Virtualization (NFV).
NFV is a promising technology for improving the elasticity and NFV is a promising technology for improving the elasticity and
efficiency of network resource utilization. In NFV environments, efficiency of network resource utilization. In NFV environments,
NSFs can be deployed in the forms of software-based virtual instances NSFs can be deployed in the forms of software-based virtual instances
rather than physical appliances. Virtualizing NSFs makes it possible rather than physical appliances. Virtualizing NSFs makes it possible
to rapidly and flexibly respond to the amount of service requests by to rapidly and flexibly respond to the amount of service requests by
dynamically increasing or decreasing the number of NSF instances. dynamically increasing or decreasing the number of NSF instances.
Moreover, NFV technology facilitates flexibly including or excluding Moreover, NFV technology facilitates flexibly including or excluding
NSFs from multiple security solution vendors according to the changes NSFs from multiple security solution vendors according to the changes
on security requirements. In order to take advantages of the NFV on security requirements. In order to take advantages of the NFV
technology, the I2NSF framework can be implemented on top of an NFV technology, the I2NSF framework can be implemented on top of an NFV
infrastructure as show in Figure 4. infrastructure as show in Figure 5.
Figure 4 shows an I2NSF framework implementation based on the NFV Figure 5 shows an I2NSF framework implementation based on the NFV
reference architecture that the European Telecommunications Standards reference architecture that the European Telecommunications Standards
Institute (ETSI) defines [ETSI-NFV]. The NSFs are deployed as Institute (ETSI) defines [ETSI-NFV]. The NSFs are deployed as
virtual network functions (VNFs) in Figure 4. The Developer's virtual network functions (VNFs) in Figure 5. The Developer's
Management System (DMS) in the I2NSF framework is responsible for Management System (DMS) in the I2NSF framework is responsible for
registering capability information of NSFs into the Security registering capability information of NSFs into the Security
Controller. Those NSFs are created or removed by a virtual network Controller. Those NSFs are created or removed by a virtual network
functions manager (VNFM) in the NFV architecture that performs the functions manager (VNFM) in the NFV architecture that performs the
life-cycle management of VNFs. The Security Controller controls and life-cycle management of VNFs. The Security Controller controls and
monitors the configurations (e.g., function parameters and security monitors the configurations (e.g., function parameters and security
policy rules) of VNFs. Both the DMS and Security Controller can be policy rules) of VNFs. Both the DMS and Security Controller can be
implemented as the Element Managements (EMs) in the NFV architecture. implemented as the Element Managements (EMs) in the NFV architecture.
Finally, the I2NSF User can be implemented as OSS/BSS (Operational Finally, the I2NSF User can be implemented as OSS/BSS (Operational
Support Systems/Business Support Systems) in the NFV architecture Support Systems/Business Support Systems) in the NFV architecture
skipping to change at page 19, line 26 skipping to change at page 20, line 26
notifies the Security Controller of the NSF instance. notifies the Security Controller of the NSF instance.
6. After being notified of the created NSF instance, the Security 6. After being notified of the created NSF instance, the Security
Controller delivers low-level security policy rules to the NSF Controller delivers low-level security policy rules to the NSF
instance for policy enforcement. instance for policy enforcement.
We can conclude that the I2NSF framework can be implemented based on We can conclude that the I2NSF framework can be implemented based on
the NFV architecture framework. Note that the registration of the the NFV architecture framework. Note that the registration of the
capabilities of NSFs is performed through the Registration Interface capabilities of NSFs is performed through the Registration Interface
and the lifecycle management for NSFs (VNFs) is performed through the and the lifecycle management for NSFs (VNFs) is performed through the
Ve-Vnfm interface between the DMS and VNFM, as shown in Figure 4. Ve-Vnfm interface between the DMS and VNFM, as shown in Figure 5.
More details about the I2NSF framework based on the NFV reference More details about the I2NSF framework based on the NFV reference
architecture are described in [i2nsf-nfv-architecture]. architecture are described in [i2nsf-nfv-architecture].
8. Security Considerations 8. Security Considerations
The same security considerations for the I2NSF framework [RFC8329] The same security considerations for the I2NSF framework [RFC8329]
are applicable to this document. are applicable to this document.
This document shares all the security issues of SDN that are This document shares all the security issues of SDN that are
specified in the "Security Considerations" section of [ITU-T.Y.3300]. specified in the "Security Considerations" section of [ITU-T.Y.3300].
skipping to change at page 20, line 29 skipping to change at page 21, line 29
o Se-Hui Lee (Korea Telecom) o Se-Hui Lee (Korea Telecom)
o Mohamed Boucadair (Orange) o Mohamed Boucadair (Orange)
11. References 11. References
11.1. Normative References 11.1. Normative References
[ETSI-NFV] [ETSI-NFV]
ETSI GS NFV 002 V1.1.1, "Network Functions Virtualisation "Network Functions Virtualisation (NFV); Architectural
(NFV); Architectural Framework", Available: Framework", Available:
https://www.etsi.org/deliver/etsi_gs/ https://www.etsi.org/deliver/etsi_gs/
nfv/001_099/002/01.01.01_60/gs_nfv002v010101p.pdf, October nfv/001_099/002/01.01.01_60/gs_nfv002v010101p.pdf, October
2013. 2013.
[ITU-T.Y.3300] [ITU-T.Y.3300]
Recommendation ITU-T Y.3300, "Framework of Software- "Framework of Software-Defined Networking",
Defined Networking", Available: https://www.itu.int/rec/T- Available: https://www.itu.int/rec/T-REC-Y.3300-201406-I,
REC-Y.3300-201406-I, June 2014. June 2014.
[NFV-Terminology] [NFV-Terminology]
ETSI GS NFV 003 V1.2.1, "Network Functions Virtualisation "Network Functions Virtualisation (NFV); Terminology for
(NFV); Terminology for Main Concepts in NFV", Available: Main Concepts in NFV", Available:
https://www.etsi.org/deliver/etsi_gs/ https://www.etsi.org/deliver/etsi_gs/
NFV/001_099/003/01.02.01_60/gs_nfv003v010201p.pdf, NFV/001_099/003/01.02.01_60/gs_nfv003v010201p.pdf,
December 2014. December 2014.
[ONF-OpenFlow] [ONF-OpenFlow]
ONF, "OpenFlow Switch Specification (Version 1.4.0)", "OpenFlow Switch Specification (Version 1.4.0)",
Available: https://www.opennetworking.org/wp- Available: https://www.opennetworking.org/wp-
content/uploads/2014/10/openflow-spec-v1.4.0.pdf, October content/uploads/2014/10/openflow-spec-v1.4.0.pdf, October
2013. 2013.
[ONF-SDN-Architecture] [ONF-SDN-Architecture]
ONF TR-521, "SDN Architecture (Issue 1.1)", Available: "SDN Architecture (Issue 1.1)", Available:
https://www.opennetworking.org/wp- https://www.opennetworking.org/wp-
content/uploads/2014/10/TR- content/uploads/2014/10/TR-
521_SDN_Architecture_issue_1.1.pdf, June 2016. 521_SDN_Architecture_issue_1.1.pdf, June 2016.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020, Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010. October 2010.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)", Bierman, "Network Configuration Protocol (NETCONF)",
skipping to change at page 21, line 51 skipping to change at page 22, line 51
11.2. Informative References 11.2. Informative References
[AVANT-GUARD] [AVANT-GUARD]
Shin, S., Yegneswaran, V., Porras, P., and G. Gu, "AVANT- Shin, S., Yegneswaran, V., Porras, P., and G. Gu, "AVANT-
GUARD: Scalable and Vigilant Switch Flow Management in GUARD: Scalable and Vigilant Switch Flow Management in
Software-Defined Networks", ACM CCS, November 2013. Software-Defined Networks", ACM CCS, November 2013.
[consumer-facing-inf-dm] [consumer-facing-inf-dm]
Jeong, J., Kim, E., Ahn, T., Kumar, R., and S. Hares, Jeong, J., Kim, E., Ahn, T., Kumar, R., and S. Hares,
"I2NSF Consumer-Facing Interface YANG Data Model", draft- "I2NSF Consumer-Facing Interface YANG Data Model", draft-
ietf-i2nsf-consumer-facing-interface-dm-02 (work in ietf-i2nsf-consumer-facing-interface-dm-03 (work in
progress), November 2018. progress), March 2019.
[consumer-facing-inf-im] [ETSI-NFV-MANO]
Kumar, R., Lohiya, A., Qi, D., Bitar, N., Palislamovic, "Network Functions Virtualisation (NFV); Management and
S., Xia, L., and J. Jeong, "Information Model for Orchestration", Available:
Consumer-Facing Interface to Security Controller", draft- https://www.etsi.org/deliver/etsi_gs/nfv-
kumar-i2nsf-client-facing-interface-im-07 (work in man/001_099/001/01.01.01_60/gs_nfv-man001v010101p.pdf,
progress), July 2018. December 2014.
[i2nsf-nfv-architecture] [i2nsf-nfv-architecture]
Yang, H., Kim, Y., Jeong, J., and J. Kim, "I2NSF on the Yang, H., Kim, Y., Jeong, J., and J. Kim, "I2NSF on the
NFV Reference Architecture", draft-yang-i2nsf-nfv- NFV Reference Architecture", draft-yang-i2nsf-nfv-
architecture-04 (work in progress), November 2018. architecture-04 (work in progress), November 2018.
[i2nsf-nsf-cap-im] [i2nsf-nsf-cap-im]
Xia, L., Strassner, J., Basile, C., and D. Lopez, Xia, L., Strassner, J., Basile, C., and D. Lopez,
"Information Model of NSFs Capabilities", draft-ietf- "Information Model of NSFs Capabilities", draft-ietf-
i2nsf-capability-04 (work in progress), October 2018. i2nsf-capability-04 (work in progress), October 2018.
[i2nsf-terminology] [i2nsf-terminology]
Hares, S., Strassner, J., Lopez, D., Xia, L., and H. Hares, S., Strassner, J., Lopez, D., Xia, L., and H.
Birkholz, "Interface to Network Security Functions (I2NSF) Birkholz, "Interface to Network Security Functions (I2NSF)
Terminology", draft-ietf-i2nsf-terminology-06 (work in Terminology", draft-ietf-i2nsf-terminology-07 (work in
progress), July 2018. progress), January 2019.
[ITU-T.X.1252] [ITU-T.X.1252]
Recommendation ITU-T X.1252, "Baseline Identity Management "Baseline Identity Management Terms and Definitions",
Terms and Definitions", April 2010. April 2010.
[ITU-T.X.800] [ITU-T.X.800]
Recommendation ITU-T X.800, "Security Architecture for "Security Architecture for Open Systems Interconnection
Open Systems Interconnection for CCITT Applications", for CCITT Applications", March 1991.
March 1991.
[nsf-facing-inf-dm] [nsf-facing-inf-dm]
Kim, J., Jeong, J., Park, J., Hares, S., and Q. Lin, Kim, J., Jeong, J., Park, J., Hares, S., and Q. Lin,
"I2NSF Network Security Function-Facing Interface YANG "I2NSF Network Security Function-Facing Interface YANG
Data Model", draft-ietf-i2nsf-nsf-facing-interface-dm-02 Data Model", draft-ietf-i2nsf-nsf-facing-interface-dm-03
(work in progress), November 2018. (work in progress), March 2019.
[nsf-monitoring-dm] [nsf-monitoring-dm]
Jeong, J., Kim, J., Hong, D., Hares, S., Xia, L., and H. Jeong, J., Chung, C., Hares, S., Xia, L., and H. Birkholz,
Birkholz, "A YANG Data Model for Monitoring I2NSF Network "A YANG Data Model for Monitoring I2NSF Network Security
Security Functions", draft-hong-i2nsf-nsf-monitoring-data- Functions", draft-ietf-i2nsf-nsf-monitoring-data-model-00
model-06 (work in progress), November 2018. (work in progress), March 2019.
[nsf-triggered-steering] [nsf-triggered-steering]
Hyun, S., Jeong, J., Park, J., and S. Hares, "Service Hyun, S., Jeong, J., Park, J., and S. Hares, "Service
Function Chaining-Enabled I2NSF Architecture", draft-hyun- Function Chaining-Enabled I2NSF Architecture", draft-hyun-
i2nsf-nsf-triggered-steering-06 (work in progress), July i2nsf-nsf-triggered-steering-06 (work in progress), July
2018. 2018.
[opsawg-firewalls] [opsawg-firewalls]
Baker, F. and P. Hoffman, "On Firewalls in Internet Baker, F. and P. Hoffman, "On Firewalls in Internet
Security", draft-ietf-opsawg-firewalls-01 (work in Security", draft-ietf-opsawg-firewalls-01 (work in
progress), October 2012. progress), October 2012.
[policy-translation] [policy-translation]
Yang, J., Jeong, J., and J. Kim, "Security Policy Yang, J., Jeong, J., and J. Kim, "Security Policy
Translation in Interface to Network Security Functions", Translation in Interface to Network Security Functions",
draft-yang-i2nsf-security-policy-translation-02 (work in draft-yang-i2nsf-security-policy-translation-03 (work in
progress), October 2018. progress), March 2019.
[registration-inf-dm] [registration-inf-dm]
Hyun, S., Jeong, J., Roh, T., Wi, S., and J. Park, "I2NSF Hyun, S., Jeong, J., Roh, T., Wi, S., and J. Park, "I2NSF
Registration Interface YANG Data Model", draft-ietf-i2nsf- Registration Interface YANG Data Model", draft-ietf-i2nsf-
registration-interface-dm-01 (work in progress), November registration-interface-dm-02 (work in progress), March
2018. 2019.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006. Description Protocol", RFC 4566, July 2006.
Appendix A. Changes from draft-ietf-i2nsf-applicability-07 [VNF-ONBOARDING]
"VNF Onboarding", Available:
The following changes have been made from draft-ietf-i2nsf- https://wiki.opnfv.org/display/mano/VNF+Onboarding,
applicability-07: November 2016.
o This version has reflected all the comments from Eric Rescorla who
is a Security Area Director as follows.
o In Section 1, Network Security Function (NFV) is defined in the
viewpoint of the I2NSF framework.
o In Section 1, a user using the I2NSF User is clarified as a system
administrator in the I2NSF framework.
o In Section 1, as the applicability of the I2NSF framework, four
different scenarios are represented with a standard bulleted list.
o The standard document about ETSI-NFV is moved to Normative Appendix A. Changes from draft-ietf-i2nsf-applicability-08
References.
o In Section 2, key terms (e.g., Network Function, Network Security The following changes have been made from draft-ietf-i2nsf-
Function, Network Functions Virtualization, and Servive Function applicability-08:
Chaining) are internally defined along with the reference to open
specifications.
o In Section 2, the definition of Firewall is corrected such that o This version has reflected the additional comments from Eric
some suspicious packets are inspected by the firewall rather than Rescorla who is a Security Area Director as follows.
every packet.
o In Section 3, for a Developer's Management System, the problem of o In Section 3, for a Developer's Management System, the problem of
an inside attacker is addressed, and a possible solution for the an inside attacker is addressed, and a possible solution for the
inside attacks is suggested through I2NSF NSF monitoring inside attacks is suggested through I2NSF NSF monitoring
functionality. functionality. Also, some restrictions on the role of the DMS are
required to deal with the inside attacks.
o In Section 4, an XML file for the RESTCONF/YANG for the time- o In Section 4, an XML code for the time-dependent web access
dependent web access control is pointed out with a reference to control is explained as an example.
the Consumer-Facing Interface's data model
[consumer-facing-inf-dm].
o In Section 6, the definitions of an SDN forwarding element and an o In Section 6, the definitions of an SDN forwarding element and an
NSF are clarified such that an SDN forwarding element is a switch NSF are clarified such that an SDN forwarding element is a switch
running as either a hardware middle box or a software virtual running as either a hardware middle box or a software virtual
switch, and an NSF is a virtual network function for a security switch, and an NSF is a virtual network function for a security
service. service. It also discusses about how to determine whether a given
software element in virtualized environments is an NSF or a
o In Section 6.3, a flow forwarding path management scheme in virtualized switch.
[AVANT-GUARD] is described in a self-contained way as follows.
For DDoS-attack mitigation, the forwarding of traffic flows in
switches can be dynamically configured such that malicious traffic
flows are handled by the paths separated from normal traffic flows
in order to minimize the impact of those malicious traffic on the
the servers. This flow path separation can be done by a flow
forwarding path management scheme based on [AVANT-GUARD].
o Some typos are corrected such as "Interner -> Internet",
"Registation -> Registration", "The low-level security rules for
web filter checks -> The low-level security rules for web filter
check", "fltering -> filtering", "illegal packets -> malicious
packets", "manipulate rules -> configure rules", "managenent ->
management", and "DDoS-attack mitigation operations -> DDoS-attack
mitigation".
Authors' Addresses Authors' Addresses
Jaehoon Paul Jeong Jaehoon Paul Jeong
Department of Software Department of Software
Sungkyunkwan University Sungkyunkwan University
2066 Seobu-Ro, Jangan-Gu 2066 Seobu-Ro, Jangan-Gu
Suwon, Gyeonggi-Do 16419 Suwon, Gyeonggi-Do 16419
Republic of Korea Republic of Korea
 End of changes. 48 change blocks. 
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