draft-ietf-babel-dtls-01.txt   draft-ietf-babel-dtls-02.txt 
Network Working Group A. Decimo Network Working Group A. Decimo
Internet-Draft IRIF, University of Paris-Diderot Internet-Draft IRIF, University of Paris-Diderot
Updates: 6126bis (if approved) D. Schinazi Updates: 6126bis (if approved) D. Schinazi
Intended status: Standards Track Apple Inc. Intended status: Standards Track Google LLC
Expires: April 11, 2019 J. Chroboczek Expires: May 18, 2019 J. Chroboczek
IRIF, University of Paris-Diderot IRIF, University of Paris-Diderot
October 8, 2018 November 14, 2018
Babel Routing Protocol over Datagram Transport Layer Security Babel Routing Protocol over Datagram Transport Layer Security
draft-ietf-babel-dtls-01 draft-ietf-babel-dtls-02
Abstract Abstract
The Babel Routing Protocol does not contain any means to authenticate The Babel Routing Protocol does not contain any means to authenticate
neighbours or protect messages sent between them. This documents neighbours or protect messages sent between them. This documents
describes a mechanism to ensure these properties, using Datagram describes a mechanism to ensure these properties, using Datagram
Transport Layer Security (DTLS). This document updates RFC 6126bis. Transport Layer Security (DTLS). This document updates RFC 6126bis.
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 April 11, 2019. This Internet-Draft will expire on May 18, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 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
1.1. Specification of Requirements . . . . . . . . . . . . . . 2 1.1. Specification of Requirements . . . . . . . . . . . . . . 2
1.2. Applicability . . . . . . . . . . . . . . . . . . . . . . 2 1.2. Applicability . . . . . . . . . . . . . . . . . . . . . . 3
2. Operation of the Protocol . . . . . . . . . . . . . . . . . . 3 2. Operation of the Protocol . . . . . . . . . . . . . . . . . . 3
2.1. DTLS Connection Initiation . . . . . . . . . . . . . . . 3 2.1. DTLS Connection Initiation . . . . . . . . . . . . . . . 3
2.2. Protocol Encoding . . . . . . . . . . . . . . . . . . . . 4 2.2. Protocol Encoding . . . . . . . . . . . . . . . . . . . . 4
2.3. Transmission . . . . . . . . . . . . . . . . . . . . . . 4 2.3. Transmission . . . . . . . . . . . . . . . . . . . . . . 4
2.4. Reception . . . . . . . . . . . . . . . . . . . . . . . . 4 2.4. Reception . . . . . . . . . . . . . . . . . . . . . . . . 4
2.5. Neighbour table entry . . . . . . . . . . . . . . . . . . 4 2.5. Neighbour table entry . . . . . . . . . . . . . . . . . . 5
2.6. Simultaneous operation of both Babel over DTLS and
unprotected Babel . . . . . . . . . . . . . . . . . . . . 5
3. Interface Maximum Transmission Unit Issues . . . . . . . . . 5 3. Interface Maximum Transmission Unit Issues . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. Normative References . . . . . . . . . . . . . . . . . . 6 6.1. Normative References . . . . . . . . . . . . . . . . . . 6
6.2. Informative References . . . . . . . . . . . . . . . . . 6 6.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Performance Considerations . . . . . . . . . . . . . 7 Appendix A. Performance Considerations . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
The Babel Routing Protocol [RFC6126bis] does not contain any means to The Babel Routing Protocol [RFC6126bis] does not contain any means to
authenticate neighbours or protect messages sent between them. authenticate neighbours or protect messages sent between them.
Because of this, an attacker is able to send maliciously crafted Because of this, an attacker is able to send maliciously crafted
Babel messages which could lead a network to route traffic to an Babel messages which could lead a network to route traffic to an
attacker or to an under-resourced target causing denial of service. attacker or to an under-resourced target causing denial of service.
This documents describes a mechanism to prevent such attacks, using This documents describes a mechanism to prevent such attacks, using
Datagram Transport Layer Security (DTLS) [RFC6347]. Datagram Transport Layer Security (DTLS) [RFC6347].
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1.1. Specification of Requirements 1.1. Specification of Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
1.2. Applicability 1.2. Applicability
The current two main mechanisms for securing Babel are Babel over The protocol described in this document protects Babel packets with
DTLS (as described in this document) and Babel Cryptographic DTLS. As such, it inherits the features offered by DTLS, notably
Authentication [BabelHMAC]. The latter has the advantages of being authentication, integrity, replay protection, confidentiality and
simpler and not requiring a dependency on DTLS, therefore asymmetric keying. It is therefore expected to be applicable in a
implementers are encouraged to consider it in preference to the wide range of environments.
mechanism defined in this document whenever both are applicable to a
given deployment. Both mechanisms ensure integrity of messages and
prevent message replay.
However, DTLS offers several features that are not provided by Babel
Cryptographic Authentication, therefore Babel over DTLS is applicable
in cases where those features are needed. Examples of such features
include:
o Asymmetric keys. DTLS allows authentication via asymmetric keys, There exists another mechanism for securing Babel, namely Babel HMAC
which allows a finer granularity of trust per-peer, and allows for authentication [BABEL-HMAC]. HMAC only offers very basic features,
revocation. namely authentication, integrity and replay protection with a small
number of symmetric keys.
o Confidentiality of data. DTLS encrypts payloads, preventing an Since HMAC authentication is simpler, requires fewer changes to the
on-link attacker from observing the routing table. Babel protocol, and avoids a dependency on DTLS, its use is
RECOMMENDED in deployments where both protocols are equally
applicable.
2. Operation of the Protocol 2. Operation of the Protocol
Babel over DTLS requires changes to how Babel is operated, for two Babel over DTLS requires some changes to how Babel operates. First,
reasons. Firstly, because DTLS introduces the concepts of client and DTLS is a client-server protocol, while Babel is a peer-to-peer
server, while Babel is a peer-to-peer protocol. Secondly, DTLS can protocol. Second, DTLS can only protect unicast communication, while
only protect unicast, while Babel TLVs can be sent over both unicast Babel packets can be sent over to both unicast and multicast
and multicast. destinations.
2.1. DTLS Connection Initiation 2.1. DTLS Connection Initiation
All Babel over DTLS nodes MUST act as DTLS servers on the "babel- All Babel over DTLS nodes MUST act as DTLS servers on the "babel-
dtls" port (UDP port TBD), and MUST listen for multicast traffic on dtls" port (UDP port TBD), and MUST listen for traffic on the
the unencrypted "babel" port (UDP port 6696). When a Babel node unencrypted "babel" port (UDP port 6696). When a Babel node
discovers a new neighbor (generally by receiving an unencrypted discovers a new neighbor (generally by receiving an unencrypted
multicast Babel packet), it compares the neighbour's IPv6 link-local multicast Babel packet), it compares the neighbour's IPv6 link-local
address with its own, using network byte ordering. If a node's address with its own, using network byte ordering. If a node's
address is lower than the recently discovered neighbor's address, it address is lower than the recently discovered neighbor's address, it
acts as a client and connects to the neighbor. In other words, the acts as a client and connects to the neighbor. In other words, the
node with the lowest address is the DTLS client for this pairwise node with the lowest address is the DTLS client for this pairwise
relationship. As an example, fe80::1:2 is considered lower than relationship. As an example, fe80::1:2 is considered lower than
fe80::2:1. The node acting as DTLS client initiates its DTLS fe80::2:1.
connection from an ephemeral UDP port. Nodes SHOULD ensure that new
client DTLS connections use different ephemeral ports from recently The node acting as DTLS client initiates its DTLS connection from an
used connections to allow servers to differentiate between the new ephemeral UDP port. Nodes SHOULD ensure that new client DTLS
and old DTLS connections. When a node receives a new DTLS connections use different ephemeral ports from recently used
connection, it MUST verify the source IP address, and reject the connections to allow servers to differentiate between the new and old
connection if the address is not an IPv6 link-local address. DTLS connections. Alternatively, nodes MAY use DTLS connection
identifiers [DTLS-CID] as a higher-entropy mechanism to distinguish
between connections.
When a node receives a new DTLS connection, it MUST verify the source
IP address, and reject the connection if the address is not an IPv6
link-local address. Nodes MUST use mutual authentication
(authenticating both client and server); servers MUST request client
authentication by sending a CertificateRequest message. If either
node fails to verify the peer's authentication, it MUST abort the
DTLS handshake. Nodes MUST only negotiate DTLS version 1.2 or
higher.
2.2. Protocol Encoding 2.2. Protocol Encoding
Babel over DTLS sends all unicast Babel packets encrypted by DTLS. Babel over DTLS sends all unicast Babel packets protected by DTLS.
The entire Babel packet, from the Magic byte at the start of the The entire Babel packet, from the Magic byte at the start of the
Babel header to the last byte of the Babel packet trailer, is sent Babel header to the last byte of the Babel packet trailer, is sent
protected by DTLS. protected by DTLS.
2.3. Transmission 2.3. Transmission
When sending packets, Babel over DTLS nodes MUST NOT send any TLVs When sending packets, Babel over DTLS nodes MUST NOT send any TLVs
over the unprotected "babel" port, with the exception of Hello TLVs over the unprotected "babel" port, with the exception of Hello TLVs
without the Unicast flag set. Babel over DTLS nodes MUST NOT send without the Unicast flag set. Babel over DTLS nodes MUST NOT send
any unprotected unicast packet. Unless some out-of-band neighbor any unprotected unicast packets. This ensures the confidentiality of
the information sent in Babel packets (e.g. the network topology) by
only sending it encrypted by DTLS. Unless some out-of-band neighbor
discovery mechanism is available, nodes SHOULD periodically send discovery mechanism is available, nodes SHOULD periodically send
unprotected multicast Hellos to ensure discovery of new neighbours. unprotected multicast Hellos to ensure discovery of new neighbours.
In order to maintain bidirectional reachability, nodes can either In order to maintain bidirectional reachability, nodes can either
rely on unprotected multicast Hellos, or also send protected unicast rely entirely on unprotected multicast Hellos, or send protected
Hellos. unicast Hellos in addition to the multicast Hellos.
Since Babel over DTLS only protects unicast packets, implementors may Since Babel over DTLS only protects unicast packets, implementors may
implement Babel over DTLS by modifying an unprotected implementation implement Babel over DTLS by modifying an unprotected implementation
of Babel, and replacing any TLV sent over multicast with a separate of Babel, and replacing any TLV sent over multicast with a separate
TLV sent over unicast for each neighbour. TLV sent over unicast for each neighbour.
2.4. Reception 2.4. Reception
Babel over DTLS nodes can receive Babel packets either protected over Babel over DTLS nodes can receive Babel packets either protected over
a DTLS connection, or unprotected directly over the "babel" port. To a DTLS connection, or unprotected directly over the "babel" port. To
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also silently ignore any unprotected Hello with the Unicast flag set. also silently ignore any unprotected Hello with the Unicast flag set.
Note that receiving an unprotected packet can still be used to Note that receiving an unprotected packet can still be used to
discover new neighbors, even when all TLVs in that packet are discover new neighbors, even when all TLVs in that packet are
silently ignored. silently ignored.
2.5. Neighbour table entry 2.5. Neighbour table entry
It is RECOMMENDED for nodes to associate the state of their DTLS It is RECOMMENDED for nodes to associate the state of their DTLS
connection with their neighbour table. When a neighbour entry is connection with their neighbour table. When a neighbour entry is
flushed from the neighbour table (Appendix A of [RFC6126bis]), its flushed from the neighbour table (Appendix A of [RFC6126bis]), its
associated DTLS state SHOULD be discarded. The node MAY send a DTLS associated DTLS state SHOULD be discarded. The node SHOULD send a
close_notify alert to the neighbour. DTLS close_notify alert to the neighbour if it believes the link is
still viable.
2.6. Simultaneous operation of both Babel over DTLS and unprotected
Babel
Implementations MAY implement both Babel over DTLS and unprotected
Babel. However, accepting unprotected Babel packets (other than
multicast Hellos) loses the security properties of Babel over DTLS.
A node MAY allow configuration options to allow unprotected Babel on
some interfaces but not others; this effectively gives nodes on that
interface the same access as authenticated nodes, and SHOULD NOT be
done unless that interface has a mechanism to authenticate nodes at a
lower layer (e.g. IPsec).
3. Interface Maximum Transmission Unit Issues 3. Interface Maximum Transmission Unit Issues
Compared to unprotected Babel, DTLS adds header, authentication tag Compared to unprotected Babel, DTLS adds header, authentication tag
and possibly block-size padding overhead to every packet. This and possibly block-size padding overhead to every packet. This
reduces the size of the Babel payload that can be carried. Nodes reduces the size of the Babel payload that can be carried. This
SHOULD compute the overhead of DTLS depending on the ciphers in use, document does not relax the packet size requirements in Section 4 of
and SHOULD NOT send Babel packets larger than the interface maximum [RFC6126bis], but recommends that DTLS overhead be taken into account
transmission unit (MTU) minus the overhead of lower layers (IP, UDP when computing maximum packet size.
and DTLS). This helps reduce the likelihood of lower-layer
fragmentation which would negatively impact performance and More precisely, nodes SHOULD compute the overhead of DTLS depending
reliability. Nodes MUST NOT send Babel packets larger than the on the ciphers in use, and SHOULD NOT send Babel packets larger than
the interface maximum transmission unit (MTU) minus the overhead of
IP, UDP and DTLS. Nodes MUST NOT send Babel packets larger than the
attached interface's MTU adjusted for known lower-layer headers (at attached interface's MTU adjusted for known lower-layer headers (at
least UDP and IP) or 512 octets, whichever is larger, but not least UDP and IP) or 512 octets, whichever is larger, but not
exceeding 2^16 - 1 adjusted for lower-layer headers. Every Babel exceeding 2^16 - 1 adjusted for lower-layer headers. Every Babel
speaker MUST be able to receive packets that are as large as any speaker MUST be able to receive packets that are as large as any
attached interface's MTU adjusted for UDP and IP headers or 512 attached interface's MTU adjusted for UDP and IP headers or 512
octets, whichever is larger. Note that this requirement on reception octets, whichever is larger. Note that this requirement on reception
does not take into account the overhead of DTLS because the peer may does not take into account the overhead of DTLS because the peer may
not have the ability to compute the overhead of DTLS and the packet not have the ability to compute the overhead of DTLS and the packet
may be fragmented by lower layers. Babel packets MUST NOT be sent in may be fragmented by lower layers.
IPv6 Jumbograms.
4. IANA Considerations 4. IANA Considerations
If this document is approved, IANA is requested to register a UDP If this document is approved, IANA is requested to register a UDP
port number, called "babel-dtls", for use by Babel over DTLS. port number, called "babel-dtls", for use by Babel over DTLS.
5. Security Considerations 5. Security Considerations
The interaction between two Babel peers requires Datagram Transport The interaction between two Babel peers requires Datagram Transport
Layer Security (DTLS) with a cipher suite offering confidentiality Layer Security (DTLS) with a cipher suite offering confidentiality
protection. The guidance given in [RFC7525] MUST be followed to protection. The guidance given in [RFC7525] MUST be followed to
avoid attacks on DTLS. The DTLS client SHOULD use the TLS avoid attacks on DTLS.
Certificate Status Request extension (Section 8 of [RFC6066]).
A malicious client might attempt to perform a high number of DTLS A malicious client might attempt to perform a high number of DTLS
handshakes with a server. As the clients are not uniquely identified handshakes with a server. As the clients are not uniquely identified
by the protocol and can be obfuscated with IPv4 address sharing and by the protocol and can be obfuscated with IPv4 address sharing and
with IPv6 temporary addresses, a server needs to mitigate the impact with IPv6 temporary addresses, a server needs to mitigate the impact
of such an attack. Such mitigation might involve rate limiting of such an attack. Such mitigation might involve rate limiting
handshakes from a given subnet or more advanced denial of service handshakes from a given subnet or more advanced denial of service
avoidance techniques beyond the scope of this document. avoidance techniques beyond the scope of this document.
6. References 6. References
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A malicious client might attempt to perform a high number of DTLS A malicious client might attempt to perform a high number of DTLS
handshakes with a server. As the clients are not uniquely identified handshakes with a server. As the clients are not uniquely identified
by the protocol and can be obfuscated with IPv4 address sharing and by the protocol and can be obfuscated with IPv4 address sharing and
with IPv6 temporary addresses, a server needs to mitigate the impact with IPv6 temporary addresses, a server needs to mitigate the impact
of such an attack. Such mitigation might involve rate limiting of such an attack. Such mitigation might involve rate limiting
handshakes from a given subnet or more advanced denial of service handshakes from a given subnet or more advanced denial of service
avoidance techniques beyond the scope of this document. avoidance techniques beyond the scope of this document.
6. References 6. References
6.1. Normative References 6.1. 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,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC6126bis] [RFC6126bis]
Chroboczek, J. and D. Schinazi, "The Babel Routing Chroboczek, J. and D. Schinazi, "The Babel Routing
Protocol", Internet Draft draft-ietf-babel-rfc6126bis-05, Protocol", Internet Draft draft-ietf-babel-rfc6126bis-07,
May 2018. November 2018.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer [RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347, Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>. January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
6.2. Informative References 6.2. Informative References
[BabelHMAC] [BABEL-HMAC]
Do, C., Kolodziejak, W., and J. Chroboczek, "Babel Do, C., Kolodziejak, W., and J. Chroboczek, "Babel
Cryptographic Authentication", Internet Draft draft-ietf- Cryptographic Authentication", Internet Draft draft-ietf-
babel-hmac-00, August 2018. babel-hmac-01, November 2018.
[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS) [DTLS-CID]
Extensions: Extension Definitions", RFC 6066, Rescorla, E., Tschofenig, H., Fossati, T., and T. Gondrom,
DOI 10.17487/RFC6066, January 2011, "Connection Identifiers for DTLS 1.2", Internet Draft
<https://www.rfc-editor.org/info/rfc6066>. draft-ietf-tls-dtls-connection-id-02, October 2018.
[RFC7250] Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J., [RFC7250] Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J.,
Weiler, S., and T. Kivinen, "Using Raw Public Keys in Weiler, S., and T. Kivinen, "Using Raw Public Keys in
Transport Layer Security (TLS) and Datagram Transport Transport Layer Security (TLS) and Datagram Transport
Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250, Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250,
June 2014, <https://www.rfc-editor.org/info/rfc7250>. June 2014, <https://www.rfc-editor.org/info/rfc7250>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer "Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security Security (TLS) and Datagram Transport Layer Security
skipping to change at page 7, line 27 skipping to change at page 8, line 5
To reduce the number of octets taken by the DTLS handshake, To reduce the number of octets taken by the DTLS handshake,
especially the size of the certificate in the ServerHello (which can especially the size of the certificate in the ServerHello (which can
be several kilobytes), Babel peers can use raw public keys [RFC7250] be several kilobytes), Babel peers can use raw public keys [RFC7250]
or the Cached Information Extension [RFC7924]. The Cached or the Cached Information Extension [RFC7924]. The Cached
Information Extension avoids transmitting the server's certificate Information Extension avoids transmitting the server's certificate
and certificate chain if the client has cached that information from and certificate chain if the client has cached that information from
a previous TLS handshake. TLS False Start [RFC7918] can reduce round a previous TLS handshake. TLS False Start [RFC7918] can reduce round
trips by allowing the TLS second flight of messages trips by allowing the TLS second flight of messages
(ChangeCipherSpec) to also contain the (encrypted) Babel packet. (ChangeCipherSpec) to also contain the (encrypted) Babel packet.
These performance considerations were inspired from the ones for DNS Appendix B. Acknowledgments
over DTLS [RFC8094].
The authors would like to thank Thomas Fossati, Gabriel Kerneis,
Antoni Przygienda, Markus Stenberg, Dave Taht, and Martin Thomson for
their input and contributions. The performance considerations in
this document were inspired from the ones for DNS over DTLS
[RFC8094].
Authors' Addresses Authors' Addresses
Antonin Decimo Antonin Decimo
IRIF, University of Paris-Diderot IRIF, University of Paris-Diderot
Paris Paris
France France
Email: antonin.decimo@gmail.com Email: antonin.decimo@gmail.com
David Schinazi David Schinazi
Apple Inc. Google LLC
One Apple Park Way 1600 Amphitheatre Parkway
Cupertino, California 95014 Mountain View, California 94043
USA USA
Email: dschinazi@apple.com Email: dschinazi.ietf@gmail.com
Juliusz Chroboczek Juliusz Chroboczek
IRIF, University of Paris-Diderot IRIF, University of Paris-Diderot
Case 7014 Case 7014
75205 Paris Cedex 13 75205 Paris Cedex 13
France France
Email: jch@irif.fr Email: jch@irif.fr
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