draft-ietf-savi-mix-15.txt   rfc8074.txt 
SAVI J. Bi Internet Engineering Task Force (IETF) J. Bi
Internet-Draft Tsinghua University Request for Comments: 8074 Tsinghua University
Intended status: Standards Track G. Yao Category: Standards Track G. Yao
Expires: July 5, 2017 Tsinghua University/Baidu ISSN: 2070-1721 Tsinghua University/Baidu
J. Halpern J. Halpern
Ericsson Ericsson
E. Levy-Abegnoli, Ed. E. Levy-Abegnoli, Ed.
Cisco Cisco
January 1, 2017 February 2017
SAVI for Mixed Address Assignment Methods Scenario Source Address Validation Improvement (SAVI)
draft-ietf-savi-mix-15 for Mixed Address Assignment Methods Scenario
Abstract Abstract
In networks that use multiple techniques for address assignment, the In networks that use multiple techniques for address assignment, the
spoofing of addresses assigned by each technique can be prevented spoofing of addresses assigned by each technique can be prevented
using the appropriate Source Address Validation Improvement (SAVI) using the appropriate Source Address Validation Improvement (SAVI)
methods. This document reviews how multiple SAVI methods can coexist methods. This document reviews how multiple SAVI methods can coexist
in a single SAVI device and collisions are resolved when the same in a single SAVI device and how collisions are resolved when the same
binding entry is discovered by two or more methods. binding entry is discovered by two or more methods.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on July 5, 2017. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc8074.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 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 . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Problem Scope . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Problem Scope . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Recommendations for assignment separation . . . . . . . . . . 5 5. Recommendations for Assignment Separation . . . . . . . . . . 6
6. Resolving binding collisions . . . . . . . . . . . . . . . . 6 6. Resolving Binding Collisions . . . . . . . . . . . . . . . . 6
6.1. Same Address on Different Binding Anchors . . . . . . . . 6 6.1. Same Address on Different Binding Anchors . . . . . . . . 6
6.1.1. Basic preference . . . . . . . . . . . . . . . . . . 6 6.1.1. Basic Preference . . . . . . . . . . . . . . . . . . 7
6.1.2. Exceptions . . . . . . . . . . . . . . . . . . . . . 7 6.1.2. Exceptions . . . . . . . . . . . . . . . . . . . . . 7
6.1.3. Multiple SAVI Device Scenario . . . . . . . . . . . . 8 6.1.3. Multiple SAVI Device Scenario . . . . . . . . . . . . 8
6.2. Same Address on the Same Binding Anchor . . . . . . . . . 8 6.2. Same Address on the Same Binding Anchor . . . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 9 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 9
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
10. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 9 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 10.1. Normative References . . . . . . . . . . . . . . . . . . 10
11.1. Normative References . . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . 11
11.2. Informative References . . . . . . . . . . . . . . . . . 10 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction 1. Introduction
There are currently several Source Address Validation Improvement There are currently several Source Address Validation Improvement
(SAVI) documents ([RFC6620], [RFC7513] and [RFC7219]) that describe (SAVI) documents ([RFC6620], [RFC7513], and [RFC7219]) that describe
the different methods by which a switch can discover and record the different methods by which a switch can discover and record
bindings between a node's IP address and a binding anchor and use bindings between a node's IP address and a binding anchor and use
that binding to perform source address validation. Each of these that binding to perform source address validation. Each of these
documents specifies how to learn on-link addresses, based on the documents specifies how to learn on-link addresses, based on the
technique used for their assignment, respectively: StateLess technique used for their assignment: StateLess Address
Autoconfiguration (SLAAC), Dynamic Host Control Protocol (DHCP) and Autoconfiguration (SLAAC), the Dynamic Host Control Protocol (DHCP),
Secure Neighbor Discovery (SeND). Each of these documents describes and Secure Neighbor Discovery (SEND), respectively. Each of these
separately how one particular SAVI method deals with address documents describes separately how one particular SAVI method deals
collisions (same address, different binding anchor). with address collisions (same address but different binding anchor).
While multiple IP assignment techniques can be used in the same While multiple IP assignment techniques can be used in the same layer
layer-2 domain, this means that a single SAVI device might have to 2 domain, this means that a single SAVI device might have to deal
deal with a combination or mix of SAVI methods. The purpose of this with a combination or mix of SAVI methods. The purpose of this
document is to provide recommendations to avoid collisions and to document is to provide recommendations to avoid collisions and to
review collisions handling when two or more such methods come up with review collision handling when two or more such methods come up with
competing bindings. competing bindings.
2. Requirements Language 2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
3. Problem Scope 3. Problem Scope
Three different IP address assignment techniques have been analyzed Three different IP address assignment techniques have been analyzed
for SAVI: for SAVI:
1. StateLess Address AutoConfiguration (SLAAC) - analyzed in SAVI- 1. StateLess Address Autoconfiguration (SLAAC) -- analyzed in FCFS
FCFS[RFC6620] SAVI (First-Come, First-Served) [RFC6620]
2. Dynamic Host Control Protocol address assignment (DHCP) - 2. Dynamic Host Control Protocol address assignment (DHCP) --
analyzed in SAVI-DHCP[RFC7513] analyzed in SAVI-DHCP [RFC7513]
3. Secure Neighbor Discovery (SeND) address assignment, analyzed in 3. Secure Neighbor Discovery (SEND) address assignment -- analyzed
SAVI-SEND[RFC7219] in SEND SAVI [RFC7219]
In addition, there is a fourth technique for managing (i.e., In addition, there is a fourth technique for managing (i.e.,
creation, management, deletion) a binding on the switch, referred to creation, management, and deletion) a binding on the switch, referred
as "manual". It is based on manual binding configuration. Because to as "manual". It is based on manual binding configuration. How to
how to manage manual bindings is determined by operators, there is manage manual bindings is determined by operators, so there is not a
not a new SAVI method for manual addresses. new SAVI method for manual addresses.
All combinations of address assignment techniques can coexist within All combinations of address assignment techniques can coexist within
a layer-2 domain. A SAVI device MUST implement the corresponding a layer 2 domain. A SAVI device MUST implement the corresponding
binding setup methods (referred to as a "SAVI method") for each such binding setup methods (referred to as "SAVI methods") for each such
technique that is in use if it is to provide Source Address technique that is in use if it is to provide source address
Validation. validation.
SAVI methods are normally viewed as independent from each other, each SAVI methods are normally viewed as independent from each other, each
one handling its own entries. If multiple methods are used in the one handling its own entries. If multiple methods are used in the
same device without coordination, each method will attempt to reject same device without coordination, each method will attempt to reject
packets sourced with any addresses that method did not discover. To packets sourced with any addresses that method did not discover. To
prevent addresses discovered by one SAVI method from being filtered prevent addresses discovered by one SAVI method from being filtered
out by another method, the SAVI binding table SHOULD be shared by all out by another method, the SAVI binding table SHOULD be shared by all
the SAVI methods in use in the device. This in turn could create the SAVI methods in use in the device. This in turn could create
some conflict when the same entry is discovered by two different some conflict when the same entry is discovered by two different
methods. The purpose of this document is of two folds: provide methods. The purpose of this document is twofold: to provide
recommendations and methods to avoid conflicts, and to resolve recommendations and methods to avoid conflicts and to resolve
conflicts when they happen. Collisions happening within a given conflicts when they happen. Collisions happening within a given
method are outside the scope of this document. method are outside the scope of this document.
4. Architecture 4. Architecture
A SAVI device may implement and use multiple SAVI methods. This A SAVI device may implement and use multiple SAVI methods. This
mechanism, called SAVI-MIX, is proposed as a arbiter of the binding mechanism, called "SAVI-MIX", is proposed as an arbiter of the
generation algorithms from these multiple methods, generating the binding generation algorithms from these multiple methods, generating
final binding entries as illustrated in Figure 1. Once a SAVI method the final binding entries as illustrated in Figure 1. Once a SAVI
generates a candidate binding, it will request SAVI-MIX to set up a method generates a candidate binding, it will request that SAVI-MIX
corresponding entry in the binding table. Then SAVI-MIX will check set up a corresponding entry in the binding table. Then, SAVI-MIX
if there is any conflict in the binding table. A new binding will be will check if there is any conflict in the binding table. A new
generated if there is no conflict. If there is a conflict, SAVI-MIX binding will be generated if there is no conflict. If there is a
will determine whether to replace the existing binding or reject the conflict, SAVI-MIX will determine whether to replace the existing
candidate binding based on the policies specified in Section 6. binding or reject the candidate binding based on the policies
specified in Section 6.
As a result of this, the packet filtering in the SAVI device will not As a result of this, the packet filtering in the SAVI device will not
be performed by each SAVI method separately. Instead, the table be performed by each SAVI method separately. Instead, the table
resulting from applying SAVI-MIX will be used to perform filtering. resulting from applying SAVI-MIX will be used to perform filtering.
Thus the filtering is based on the combined results of the differents Thus, the filtering is based on the combined results of the different
SAVI mechanisms. It is beyond the scope of this document to describe SAVI mechanisms. It is beyond the scope of this document to describe
the details of the filtering mechanism and its use of the combined the details of the filtering mechanism and its use of the combined
SAVI binding table. SAVI binding table.
+--------------------------------------------------------+ +--------------------------------------------------------+
| | | |
| SAVI Device | | SAVI Device |
| | | |
| | | |
| +------+ +------+ +------+ | | +------+ +------+ +------+ |
skipping to change at page 5, line 33 skipping to change at page 5, line 33
| | | | | |
| v Final Binding | | v Final Binding |
| +--------------+ | | +--------------+ |
| | Binding | | | | Binding | |
| | | | | | | |
| | Table | | | | Table | |
| +--------------+ | | +--------------+ |
| | | |
+--------------------------------------------------------+ +--------------------------------------------------------+
Figure 1: SAVI-Mix Architecture Figure 1: SAVI-MIX Architecture
Each entry in the binding table will contain the following fields: Each entry in the binding table will contain the following fields:
1. IP source address 1. IP source address
2. Binding anchor[RFC7039] 2. Binding anchor [RFC7039]
3. Lifetime 3. Lifetime
4. Creation time 4. Creation time
5. Binding methods: the SAVI method used for this entry. 5. Binding methods: the SAVI method used for this entry
5. Recommendations for assignment separation 5. Recommendations for Assignment Separation
If each address assignment technique uses a separate portion of the If each address assignment technique uses a separate portion of the
IP address space, collisions won't happen. Using non overlapping IP address space, collisions won't happen. Using non-overlapping
address space across address assignment techniques, and thus across address space across address assignment techniques, and thus across
SAVI methods is therefore recommended. To that end, one should: SAVI methods, is therefore recommended. To that end, one should:
1. DHCP and SLAAC: use non-overlapping prefix for DHCP and SLAAC. 1. DHCP and SLAAC: use a non-overlapping prefix for DHCP and SLAAC.
Set the A bit in Prefix information option of Router Set the A bit in the Prefix Information option of the Router
Advertisement for SLAAC prefix, and set the M bit in Router Advertisement for the SLAAC prefix, and set the M bit in the
Advertisement for DHCP prefix. For detail explanations on these Router Advertisement for the DHCP prefix. For detailed
bits, refer to [RFC4861][RFC4862]. explanations of these bits, refer to [RFC4861] and [RFC4862].
2. SeND and non-SeND: avoid mixed environment (where SeND and non- 2. SEND and non-SEND: avoid mixed environments (where SEND and non-
SeND nodes are deployed) or separate the prefixes announced to SEND nodes are deployed) or separate the prefixes announced to
SeND and non-SenD nodes. One way to separate the prefixes is to SEND and non-SEND nodes. One way to separate the prefixes is to
have the router(s) announcing different (non-overlapping) have the router(s) announcing different (non-overlapping)
prefixes to SeND and to non-SeND nodes, using unicast Router prefixes to SEND and to non-SEND nodes, using unicast Router
Advertisements[RFC6085], in response to SeND/non-SeND Router Advertisements [RFC6085], in response to SEND/non-SEND Router
Solicit. Solicit.
6. Resolving binding collisions 6. Resolving Binding Collisions
In situations where collisions can not be avoided by assignment In situations where collisions cannot be avoided by assignment
separation, two cases should be considered: separation, two cases should be considered:
1. The same address is bound on two different binding anchors by 1. The same address is bound on two different binding anchors by
different SAVI methods. different SAVI methods.
2. The same address is bound on the same binding anchor by different 2. The same address is bound on the same binding anchor by different
SAVI methods. SAVI methods.
6.1. Same Address on Different Binding Anchors 6.1. Same Address on Different Binding Anchors
This would typically occur in case assignment address spaces could This would typically occur if assignment address spaces could not be
not be separated. For instance, an address is assigned by SLAAC on separated. For instance, an address is assigned by SLAAC on node X,
node X, installed in the binding table using SAVI-FCFS, anchored to installed in the binding table using FCFS SAVI, and anchored to
"anchor-X". Later, the same address is assigned by DHCP to node Y, "anchor-X". Later, the same address is assigned by DHCP to node Y,
and SAVI-DHCP will generate a candidate binding entry, anchored to and SAVI-DHCP will generate a candidate binding entry, anchored to
"anchor-Y". "anchor-Y".
6.1.1. Basic preference 6.1.1. Basic Preference
If there is any manually configured binding, the SAVI device SHOULD If there is any manually configured binding, the SAVI device SHOULD
choose the manual configured binding acnhor. choose the manually configured binding anchor.
For an address not covered by any manual bindings, the SAVI device For an address not covered by any manual bindings, the SAVI device
must decide to which binding anchor the address should be bound must decide to which binding anchor the address should be bound
(anchor-X or anchor-Y in this example). Current standard documents (anchor-X or anchor-Y in this example). Current standard documents
of address assignment methods have implied the prioritization of address assignment methods have implied the prioritization
relationship based on order in time, i.e., first-come first-served. relationship based on order in time, i.e., First-Come, First-Served.
o SLAAC: s5.4.5 of [RFC4862] o SLAAC: Section 5.4.5 of [RFC4862]
o DHCPv4: s3.1-p5 of [RFC2131] o DHCPv4: Section 3.1, Point 5 of [RFC2131]
o DHCPv6: s18.1.8 of [RFC3315] o DHCPv6: Section 18.1.8 of [RFC3315]
o SeND: s8 of [RFC3971] o SEND: Section 8 of [RFC3971]
In the absence of any configuration or protocol hint (see In the absence of any configuration or protocol hint (see
Section 6.1.2) the SAVI device SHOULD choose the first-come binding Section 6.1.2), the SAVI device SHOULD choose the first-come binding
anchor, whether it was learnt from SLAAC, SeND or DHCP. anchor, whether it was learned from SLAAC, SEND, or DHCP.
6.1.2. Exceptions 6.1.2. Exceptions
There are two identified exceptions to the general prioritization There are two identified exceptions to the general prioritization
model, one of them being CGA addresses[RFC3971], another one model, one being Cryptographically Generated Addresses (CGA)
controlled by the configuration of the switch. [RFC3971] and the other controlled by the configuration of the
switch.
6.1.2.1. CGA preference 6.1.2.1. CGA Preference
When CGA addresses are used, and a collision is detected, preference When CGA addresses are used and a collision is detected, preference
should be given to the anchor that carries the CGA credentials once should be given to the anchor that carries the CGA credentials once
they are verified, in particular the CGA parameters and the RSA they are verified, in particular, the CGA parameters and the RSA
options. Note that if an attacker was trying to replay CGA options. Note that if an attacker was trying to replay CGA
credentials, he would then compete on the base of "First-Come, First- credentials, he would then compete on the base of the "First-Come,
Served" (FCFS) principle. First-Served" (FCFS) principle.
6.1.2.2. configuration preference 6.1.2.2. Configuration Preference
For configuration driven exceptions, the SAVI device may allow the For configuration-driven exceptions, the SAVI device may allow the
configuration of a triplet ("prefix", "anchor", "method") or configuration of a triplet ("prefix", "anchor", "method") or
("address", "anchor", "method"). The "prefix" or "address" ("address", "anchor", "method"). The "prefix" or "address"
represents the address or address prefix to which this preference represents the address or address prefix to which this preference
entry applies. The "anchor" is the value of a known binding anchor entry applies. The "anchor" is the value of a known binding anchor
that this device expects to see using this address or addresses from that this device expects to see using this address or addresses from
this prefix. The "method" is the SAVI method that this device this prefix. The "method" is the SAVI method that this device
expects to use in validating address binding entries from the address expects to use in validating address binding entries from the address
or prefix. At least one of "anchor" and "method" MUST be specified. or prefix. At least one of "anchor" and "method" MUST be specified.
Later, if a DAD message [RFC4861] is received with the following Later, if a Duplicate Address Detection (DAD) message [RFC4861] is
conditions verified: received with the following conditions verified:
1. The target in the DAD message does not exist in the binding table 1. The target in the DAD message does not exist in the binding
table,
2. The target is within the configured "prefix" (or equal to 2. The target is within the configured "prefix" (or equal to
"address") "address"),
3. The anchor bound to target is different from the configured 3. The anchor bound to the target is different from the configured
anchor, when specified anchor, when specified, and
4. The configured method, if any, is different from SAVI-FCFS 4. The configured method, if any, is different from FCFS SAVI,
The switch SHOULD defend the address by responding to the DAD then the switch SHOULD defend the address by responding to the DAD
message, with a NA message, on behalf of the target node. It SHOULD message, with a Neighbor Advertisement (NA) message, on behalf of the
NOT install the entry into the binding table. The DAD message SHOULD target node. It SHOULD NOT install the entry into the binding table.
be discarded and not forwarded. Forwarding it may cause other SAVI The DAD message SHOULD be discarded and not forwarded. Forwarding it
devices to send additional defense NAs. SeND nodes in the network may cause other SAVI devices to send additional defense NAs. SEND
MUST disable the option to ignore unsecured advertisements (see s8 of nodes in the network MUST disable the option to ignore unsecured
[RFC3971]). If the option is enabled, the case is outside the scope advertisements (see Section 8 of [RFC3971]). If the option is
of this document. It is suggested to limit the rate of defense NAs enabled, the case is outside the scope of this document. It is
to reduce security threats to the switch. Or else, a malicious host suggested to limit the rate of defense NAs to reduce security threats
could consume the resource of the switch heavily with flooding DAD to the switch. Otherwise, a malicious host could consume the
messages. resource of the switch heavily with flooding DAD messages.
This will simply prevent the node from assigning the address, and This will simply prevent the node from assigning the address and will
will de-facto prioritize the configured anchor. It is especially de facto prioritize the configured anchor. It is especially useful
useful to protect well known bindings such as a static address of a to protect well-known bindings (such as a static address of a server)
server over anybody, even when the server is down. It is also a way against any other host, even when the server is down. It is also a
to give priority to a binding learnt from SAVI-DHCP over a binding way to give priority to a binding learned from SAVI-DHCP over a
for the same address, learnt from SAVI-FCFS. binding for the same address, learned from FCFS SAVI.
6.1.3. Multiple SAVI Device Scenario 6.1.3. Multiple SAVI Device Scenario
A single SAVI device doesn't have the information of all bound A single SAVI device doesn't have the information of all bound
addresses on the perimeter. Therefore it is not enough to lookup addresses on the perimeter. Therefore, it is not enough to look up
local bindings to identify a collision. However, assuming DAD is local bindings to identify a collision. However, assuming DAD is
performed throughout the security perimeter for all addresses performed throughout the security perimeter for all addresses
regardless of the assignment method, then DAD response will inform regardless of the assignment method, then the DAD response will
all SAVI devices about any collision. In that case, "First-Come, inform all SAVI devices about any collision. In that case, "First-
First- Served" will apply the same way as in a single switch Come, First-Served" will apply the same way as in a single switch
scenario. If the admin configured on one the switches a prefix (or a scenario. If the admin configured a prefix (or a single static
single static binding) to defend, the DAD response generated by this binding) on one of the switches to defend, the DAD response generated
switch will also prevent the binding to be installed on other by this switch will also prevent the binding from being installed on
switches of the perimeter. The SAVI MIX preferences of all the SAVI other switches on the perimeter. The SAVI-MIX preferences of all the
devices in the same layer-2 domain should be consistent. SAVI devices in the same layer 2 domain should be consistent.
Inconsistent configurations may cause network breaks. Inconsistent configurations may cause network breaks.
6.2. Same Address on the Same Binding Anchor 6.2. Same Address on the Same Binding Anchor
A binding may be set up on the same binding anchor by multiple A binding may be set up on the same binding anchor by multiple
methods, typically SAVI-FCFS and SAVI-DHCP. If the binding lifetimes methods, typically FCFS SAVI and SAVI-DHCP. If the binding lifetimes
obtained from the two methods are different, priority should be given obtained from the two methods are different, priority should be given
to 1) Manual configuration 2) SAVI-DHCP 3) SAVI-FCFS as the least to 1) manual configuration, 2) SAVI-DHCP, 3) and FCFS SAVI as the
authoritative. The binding will be removed when the prioritized least authoritative. The binding will be removed when the
lifetime expires, even if a less authoritative method had a longer prioritized lifetime expires, even if a less authoritative method had
lifetime. a longer lifetime.
7. Security Considerations 7. Security Considerations
Combining SAVI methods (as in SAVI MIX) does not improve on or Combining SAVI methods (as in SAVI-MIX) does not improve or eliminate
eliminate the security considerations associated with each individual the security considerations associated with each individual SAVI
SAVI method. Therefore, security considerations for each enabled method. Therefore, security considerations for each enabled SAVI
SAVI method should be addressed as described in that method's method should be addressed as described in that method's associated
associated RFC. Moreover, combining methods (as in SAVI MIX) has two RFC. Moreover, combining methods (as in SAVI-MIX) has two additional
additional implications for security. First, it may increase implications for security. First, it may increase susceptibility to
susceptibility to DoS attacks, because the SAVI binding setup rate DoS attacks, because the SAVI binding setup rate will be the sum of
will be the sum of the rates of all enabled SAVI methods. the rates of all enabled SAVI methods. Implementers must take these
Implementers must take these added resource requirements into added resource requirements into account. Second, because SAVI-MIX
account. Second, because SAVI MIX supports multiple binding supports multiple binding mechanisms, it potentially reduces the
mechanisms, it potentially reduces the security level to that of the security level to that of the weakest supported method, unless
weakest supported method, unless additional steps (e.g. requiring additional steps (e.g., requiring non-overlapping address spaces for
non-overlapping address spaces for different methods) are taken. different methods) are taken.
8. Privacy Considerations 8. Privacy Considerations
When implementing multiple SAVI methods, privacy considerations of When implementing multiple SAVI methods, privacy considerations of
all methods apply cumulatively. all methods apply cumulatively.
9. IANA Considerations 9. IANA Considerations
This memo asks the IANA for no new parameters. This document does not require any IANA registrations.
10. Acknowledgment
Thanks to Christian Vogt, Eric Nordmark, Marcelo Bagnulo Braun, David
Lamparter, Scott G. Kelly and Jari Arkko for their valuable
contributions.
11. References 10. References
11.1. Normative References 10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol", [RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
RFC 2131, DOI 10.17487/RFC2131, March 1997, RFC 2131, DOI 10.17487/RFC2131, March 1997,
<http://www.rfc-editor.org/info/rfc2131>. <http://www.rfc-editor.org/info/rfc2131>.
skipping to change at page 10, line 31 skipping to change at page 11, line 5
[RFC7219] Bagnulo, M. and A. Garcia-Martinez, "SEcure Neighbor [RFC7219] Bagnulo, M. and A. Garcia-Martinez, "SEcure Neighbor
Discovery (SEND) Source Address Validation Improvement Discovery (SEND) Source Address Validation Improvement
(SAVI)", RFC 7219, DOI 10.17487/RFC7219, May 2014, (SAVI)", RFC 7219, DOI 10.17487/RFC7219, May 2014,
<http://www.rfc-editor.org/info/rfc7219>. <http://www.rfc-editor.org/info/rfc7219>.
[RFC7513] Bi, J., Wu, J., Yao, G., and F. Baker, "Source Address [RFC7513] Bi, J., Wu, J., Yao, G., and F. Baker, "Source Address
Validation Improvement (SAVI) Solution for DHCP", Validation Improvement (SAVI) Solution for DHCP",
RFC 7513, DOI 10.17487/RFC7513, May 2015, RFC 7513, DOI 10.17487/RFC7513, May 2015,
<http://www.rfc-editor.org/info/rfc7513>. <http://www.rfc-editor.org/info/rfc7513>.
11.2. Informative References 10.2. Informative References
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007, DOI 10.17487/RFC4861, September 2007,
<http://www.rfc-editor.org/info/rfc4861>. <http://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007, DOI 10.17487/RFC4862, September 2007,
<http://www.rfc-editor.org/info/rfc4862>. <http://www.rfc-editor.org/info/rfc4862>.
[RFC7039] Wu, J., Bi, J., Bagnulo, M., Baker, F., and C. Vogt, Ed., [RFC7039] Wu, J., Bi, J., Bagnulo, M., Baker, F., and C. Vogt, Ed.,
"Source Address Validation Improvement (SAVI) Framework", "Source Address Validation Improvement (SAVI) Framework",
RFC 7039, DOI 10.17487/RFC7039, October 2013, RFC 7039, DOI 10.17487/RFC7039, October 2013,
<http://www.rfc-editor.org/info/rfc7039>. <http://www.rfc-editor.org/info/rfc7039>.
Acknowledgments
Thanks to Christian Vogt, Eric Nordmark, Marcelo Bagnulo Braun, David
Lamparter, Scott G. Kelly, and Jari Arkko for their valuable
contributions.
Authors' Addresses Authors' Addresses
Jun Bi Jun Bi
Tsinghua University Tsinghua University
Network Research Center, Tsinghua University Institute for Network Sciences and Cyberspace, Tsinghua University
Beijing 100084 Beijing 100084
China China
EMail: junbi@tsinghua.edu.cn Email: junbi@tsinghua.edu.cn
Guang Yao Guang Yao
Tsinghua University/Baidu Tsinghua University/Baidu
Baidu Science and Technology Park, Building 1 Baidu Science and Technology Park, Building 1
Beijing 100193 Beijing 100193
China China
EMail: yaoguang.china@gmail.com Email: yaoguang.china@gmail.com
Joel M. Halpern Joel M. Halpern
Ericsson Ericsson
EMail: joel.halpern@ericsson.com Email: joel.halpern@ericsson.com
Eric Levy-Abegnoli (editor) Eric Levy-Abegnoli (editor)
Cisco Systems Cisco Systems
Village d'Entreprises Green Side - 400, Avenue Roumanille Village d'Entreprises Green Side - 400, Avenue Roumanille
Biot-Sophia Antipolis 06410 Biot-Sophia Antipolis 06410
France France
EMail: elevyabe@cisco.com Email: elevyabe@cisco.com
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