One document matched: draft-boucadair-lisp-v6-compact-header-00.xml
<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd" [
<!ENTITY % RFC2119 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml">
]>
<?rfc rfcedstyle="yes" ?>
<?rfc symrefs="yes" ?>
<?rfc compact="yes" ?>
<?rfc sortrefs="yes" ?>
<?rfc toc="yes" ?>
<?rfc tocompact="yes"?>
<rfc category="exp" docName="draft-boucadair-lisp-v6-compact-header-00"
ipr="trust200902">
<front>
<title abbrev="Compact LISP Encapsulation">A Compact LISP Encapsulation
Scheme to Transport IPv4 Packets over an IPv6 Network</title>
<author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
<organization>France Telecom</organization>
<address>
<postal>
<street></street>
<city>Rennes</city>
<code>35000</code>
<country>France</country>
</postal>
<email>mohamed.boucadair@orange.com</email>
</address>
</author>
<author fullname="Christian Jacquenet" initials="C." surname="Jacquenet">
<organization>France Telecom</organization>
<address>
<postal>
<street></street>
<city>Rennes</city>
<code>35000</code>
<country>France</country>
</postal>
<email>christian.jacquenet@orange.com</email>
</address>
</author>
<date day="" month="" year="" />
<area>Internet</area>
<keyword>IPv4 service continuity</keyword>
<keyword>IPv4 address exhaustion</keyword>
<keyword>Service Availability</keyword>
<keyword>Address sharing</keyword>
<keyword>IPv6</keyword>
<keyword>Reliability</keyword>
<keyword>IPv4 over IPv6</keyword>
<abstract>
<t>The encapsulation scheme used by the Locator/ID Separation Protocol
(LISP) may sometimes raise MTU issues at the cost of possibly degrading
the overall performance of the LISP network, especially in IPv6
migration contexts. This document proposes a new, more compact,
encapsulation scheme that aims to accommodate such issues and facilitate
LISP deployment for IPv6 migration purposes, in particular.</t>
</abstract>
<note title="Requirements Language">
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in <xref
target="RFC2119">RFC 2119</xref>.</t>
</note>
</front>
<middle>
<section title="Introduction">
<t>The base specification of the Locator/ID Separation Protocol (LISP,
<xref target="RFC6830"></xref>) defines an encapsulation scheme for
transporting packets between xTR routers. When applied at the scale of
the Internet, this encapsulation scheme may raise MTU issues because of
the LISP overhead. This overhead may be aggravated when IPv6 transfer
capabilities are used to interconnect LISP sites.</t>
<t><xref target="tcp"></xref> shows the format of an encapsulated TCP
(<xref target="RFC0793"></xref>) packet over IPv6, while <xref
target="udp"></xref> covers UDP (<xref target="RFC0768"></xref>).</t>
<t><figure anchor="tcp" title="LISP IPv4-in-IPv6 Header Format (TCP)">
<artwork><![CDATA[ 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ |Version| Traffic Class | Flow Label |
/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Payload Length | Next Header=17| Hop Limit |
v +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
O + +
u | |
t + Source Routing Locator +
e | |
r + +
| |
H +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
d | |
r + +
| |
^ + Destination Routing Locator +
| | |
\ + +
\ | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port = xxxx | Dest Port = 4341 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L |N|L|E|V|I|flags| Nonce/Map-Version |
I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
S / | Instance ID/Locator-Status-Bits |
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ |Version| IHL |Type of Service| Total Length |
/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Identification |Flags| Fragment Offset |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IH | Time to Live | Protocol | Header Checksum |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Source EID |
\ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | Destination EID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port | Destination Port |
/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Sequence Number |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Acknowledgment Number |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TCP | Data | |U|A|P|R|S|F| |
| | Offset| Reserved |R|C|S|S|Y|I| Window |
| | | |G|K|H|T|N|N| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Checksum | Urgent Pointer |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | (Optional) Options |
\ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]></artwork>
</figure><figure align="right" anchor="udp"
title="LISP IPv4-in-IPv6 Header Format (UDP)">
<artwork><![CDATA[ 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ |Version| Traffic Class | Flow Label |
/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Payload Length | Next Header=17| Hop Limit |
v +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
O + +
u | |
t + Source Routing Locator +
e | |
r + +
| |
H +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
d | |
r + +
| |
^ + Destination Routing Locator +
| | |
\ + +
\ | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port = xxxx | Dest Port = 4341 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L |N|L|E|V|I|flags| Nonce/Map-Version |
I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
S / | Instance ID/Locator-Status-Bits |
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ |Version| IHL |Type of Service| Total Length |
/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Identification |Flags| Fragment Offset |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IH | Time to Live | Protocol | Header Checksum |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Source EID |
\ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | Destination EID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port | Destination Port |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure></t>
<t>This document proposes a new LISP encapsulation scheme that aims to
reduce the overhead induced by LISP encapsulation. This proposal does
not suggest to obsolete the current LISP base encapsulation mode as
defined in <xref target="RFC6830"></xref>. Rather, this document
proposes to associate a meaning with one of the reserved flag bits (see
Section 5.3 of <xref target="RFC6830"></xref>) to explicitly indicate
that, when the bit is set, compact LISP encapsulation is in use. This
bit is called the C-bit ("Compact" flag bit).</t>
<t><xref target="comp"></xref> describes a compact header format that
leads to a 8-byte overhead when transporting IPv4-over-IPv6 LISP packets
for both TCP and UDP. <xref target="cc"></xref> proposes a more compact
header with 4-byte overhead for both TCP and UDP packets.</t>
</section>
<section anchor="comp" title="A Compact LISP Header">
<t><xref target="cflag"></xref> shows the required change to the LISP
header. The "flg" bits are reserved bits for future assignment as
additional flag bits. These additional flag bits MUST each be set to
zero and MUST be ignored upon receipt. The description of the remaining
fields is the same as in <xref target="RFC6830"></xref>. Note, the
definition of the C-bit does not interfere with the functionality
provided by other flag bits.</t>
<t><figure anchor="cflag" title="C-bit in the LISP Header">
<artwork><![CDATA[OLD:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L |N|L|E|V|I|flags| Nonce/Map-Version |
I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
S / | Instance ID/Locator-Status-Bits |
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
NEW:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L |N|L|E|V|I|flg|C| Nonce/Map-Version |
I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
S / | Instance ID/Locator-Status-Bits |
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]></artwork>
</figure></t>
<t>The use of the C-bit as defined in this document is encouraged in
IPv6 migration contexts that rely upon IPv4-embedded IPv6 addresses, as
defined in <xref target="RFC6052"></xref>. Concretely, IPv4-embedded
IPv6 addresses are used to convey Source/Destination IPv4 EIDs in
Source/Destination Routing Locators. <xref target="emb"></xref>
summarizes how the IPv4-embedded IPv6 RLOCs are synthesized from IPv4
EIDs. As discussed in <xref target="RFC6052"></xref>, the "u" byte is
set to zero.</t>
<t><figure align="center" anchor="emb" title="IPv4-embedded RLOCs">
<artwork><![CDATA[ +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| RLOC Prefix (64 bits) | u | EID(32) | suffix |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
Where "suffix" is :
* the concatenation of "Protocol" field of the Internet header
as conveyed in the original packet and "source port" of the transport
header of the original packet (Source IPv4-embedded IPv6 address).
* the concatenation of a null octet and "source port" of transport
header of the original packet (Source IPv4-embedded IPv6 address).
]]></artwork>
</figure></t>
<t>Also, the TCP header is truncated as shown in <xref
target="trunc-tcp"></xref>.</t>
<t><figure align="center" anchor="trunc-tcp"
title="Truncated TCP Header">
<artwork><![CDATA[TCP Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Port | Destination Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Acknowledgment Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data | |U|A|P|R|S|F| |
| Offset| Reserved |R|C|S|S|Y|I| Window |
| | |G|K|H|T|N|N| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Checksum | Urgent Pointer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (Optional) Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Truncated TCP Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Acknowledgment Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data | |U|A|P|R|S|F| |
| Offset| Reserved |R|C|S|S|Y|I| Window |
| | |G|K|H|T|N|N| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (Optional) Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]></artwork>
</figure></t>
<t>The compact LISP header for a TCP packet is shown in <xref
target="ctcp"></xref>, while the compact LISP header for UDP is depicted
in <xref target="ctcp"></xref>.</t>
<t><figure anchor="ctcp" title="Compact LISP Header Format (TCP Case)">
<artwork><![CDATA[ 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ |Version| Traffic Class | Flow Label |
/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Payload Length | Next Header=17| Hop Limit |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
| | | |
I + Source Routing Locator (64 bits) + |
P | | S
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ R
H | u byte | Source EID ... | C
E +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
A | .... | Protocol | (Inner) Source Port | |
D +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
E | | |
R + Destination Routing Locator (64 bits) + |
| | | D
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ S
| | u byte | Destination EID ... | T
\ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
\ | .... | 00000000 |(Inner)Destination Port | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
/ | Source Port = xxxx | Dest Port = 4341 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L |N|L|E|V|I|flg|C| Nonce/Map-Version |
I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
S / | Instance ID/Locator-Status-Bits |
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Acknowledgment Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data | |U|A|P|R|S|F| |
| Offset| Reserved |R|C|S|S|Y|I| Window |
| | |G|K|H|T|N|N| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (Optional) Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]></artwork>
</figure></t>
<t><figure anchor="cudp" title="Compact LISP Header Format (UDP Case)">
<artwork><![CDATA[ 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ |Version| Traffic Class | Flow Label |
/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Payload Length | Next Header=17| Hop Limit |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
| | | |
I + Source Routing Locator (64 bits) + |
P | | S
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ R
H | u byte | Source EID ... | C
E +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
A | .... | Protocol | (Inner) Source Port | |
D +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
E | | |
R + Destination Routing Locator (64 bits) + |
| | | D
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ S
| | u byte | Destination EID ... | T
\ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
\ | .... | 00000000 |(Inner)Destination Port | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
/ | Source Port = xxxx | Dest Port = 4341 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L |N|L|E|V|I|flg|C| Nonce/Map-Version |
I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
S / | Instance ID/Locator-Status-Bits |
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure></t>
</section>
<section title="LISP Encapsulation with the Compact Header Form">
<t>Upon receipt of an IPv4 packet that needs to be forwarded over a
LISP-enabled infrastructure, the ITR proceeds as follows:<?rfc subcompact="yes" ?></t>
<section title="UDP Packets">
<t><list style="symbols">
<t>Retrieve the destination/source RLOC IPv6 prefix.</t>
<t>Concatenate the source RLOC IPv6 prefix, the u byte, the source
IPv4 address, the "Protocol" as indicated in the IP header, and
the source port number to form the source IPv6 address as
specified in <xref target="comp"></xref> for non-fragmented
packets and fragments that convey a transport header.</t>
<t>Concatenate the destination RLOC IPv6 prefix, the u byte, the
destination IPv4 address, a null octet, and the destination port
number to form the destination IPv6 address as specified in <xref
target="comp"></xref> for non-fragmented packets and fragments
that convey a transport header.</t>
<t>Remove both the IP and UDP headers of the original packet.</t>
<t>Prepend the LISP header.</t>
<t>Prepend the UDP header.</t>
<t>Prepend the IPv6 header.</t>
</list></t>
</section>
<section title="TCP Packets">
<t><list style="symbols">
<t>Retrieve the destination/source RLOC IPv6 prefix.</t>
<t>Concatenate the source RLOC IPv6 prefix, the u byte, the source
IPv4 address, the "Protocol" as indicated in the IP header, and
the source port number to form the source IPv6 address as
specified in <xref target="comp"></xref> for non-fragmented
packets and fragments that convey a transport header.</t>
<t>Concatenate the destination RLOC IPv6 prefix, the u byte, the
destination IPv4 address, a null octet, and the destination port
number to form the destination IPv6 address as specified in <xref
target="comp"></xref> for non-fragmented packets and fragments
that convey a transport header.</t>
<t>Remove the IP header and the first 4 bytes and the 4 bytes
right after the "window" field from the original TCP header.</t>
<t>Prepend the LISP header.</t>
<t>Prepend the UDP header.</t>
<t>Prepend the IPv6 header.</t>
</list></t>
</section>
<section title="Fragments">
<t><list style="symbols">
<t>Retrieve the destination/source RLOC IPv6 prefix.</t>
<t>Concatenate the source RLOC IPv6 prefix, the u byte, the source
IPv4 address, and 3 bytes the "Protocol" as indicated in the IP
header, and 2 bytes paddings of "1".</t>
<t>Concatenate the destination RLOC IPv6 prefix, the u byte, the
destination IPv4 address, and 3 bytes paddings of "1".</t>
<t>Remove both the IP header of the original packet.</t>
<t>Prepend the LISP header.</t>
<t>Prepend the UDP header.</t>
<t>Prepend the IPv6 header.</t>
</list><?rfc subcompact="no" ?></t>
</section>
</section>
<section title="LISP Decapsulation with the Compact LISP Header">
<t>Upon receipt of a LISP packet with the C-bit set, the ETR proceeds as
follows to extract the inner IP packets (<xref target="dudp"></xref> for
UDP and <xref target="dtcp"></xref> for TCP).</t>
<t>The processing of the other flag bits is not detailed in this
specification. The behavior defined in <xref target="RFC6830"></xref> is
not impacted by this specification.</t>
<t>Obviously if the C-bit is unset, xTR routers follow the behavior
defined in <xref target="RFC6830"></xref>.</t>
<t>The UDP checksum setting and validation of LISP-encapsulated packets
MUST follow the guidelines documented in Section 5.3 of <xref
target="RFC6830"></xref>.</t>
<t><?rfc subcompact="yes" ?></t>
<section anchor="dudp" title="Build an IPv4/UDP Header">
<t><list style="symbols">
<t>Check whether the destination IPv6 address matches an RLOC
prefix owned by the xTR.</t>
<t>Extract the Source EID that is encoded in positions 72 to 103
of the Source IPv6 address.</t>
<t>Extract the "Protocol" field that is encoded in positions 104
to 111 of the Source IPv6 address. This value is used to set the
corresponding field in the IPv4 header of the de-capsulated
packet.</t>
<t>Extract the Source Port that is encoded in positions 112 to 127
of the Source IPv6 address, for non-fragmented packets and
fragments that convey a transport header.</t>
<t>Extract the Destination EID that is encoded in positions 72 to
103 of the Destination IPv6 address.</t>
<t>Extract the Destination Port that is encoded in positions 112
to 127 of the Destination IPv6 address, for non-fragmented packets
and fragments that convey a transport header.</t>
<t>Remove the IPv6 header, the UDP header, and the LISP
header.</t>
<t>Use the extracted Source Port and Destination Port to build the
UDP header. Prepend the new UDP header.</t>
<t>Use the extracted Source IP address, Destination IP address,
and Protocol to build the IPv4 header.</t>
<t>Prepend the new IPv4 header.</t>
</list></t>
</section>
<section anchor="dtcp" title="Build an IPv4/TCP Header">
<t><list style="symbols">
<t>Check whether the destination IPv6 address matches an RLOC
prefix owned by the xTR.</t>
<t>Extract the Source EID that is encoded in positions 72 to 103
of the Source IPv6 address.</t>
<t>Extract the "Protocol" field that is encoded in positions 104
to 111 of the Source IPv6 address. This value is used to set the
corresponding field in the IPv4 header of the de-capsulated
packet.</t>
<t>Extract the Source Port that is encoded in positions 112 to 127
of the Source IPv6 address, for non-fragmented packets and
fragments that convey a transport header.</t>
<t>Extract the Destination EID that is encoded in positions 72 to
103 of the Destination IPv6 address.</t>
<t>Extract the Destination Port that is encoded in positions 112
to 127 of the Destination IPv6 address, for non-fragmented packets
and fragments that convey a transport header.</t>
<t>Remove the IPv6 header, UDP header, and LISP header.</t>
<t>For non-fragmented packets and fragments that convey a
transport header, prepend 4 bytes with the source/destination port
number and insert 4 bytes right after the "window" field to build
a proper TCP header. The extracted Source Port and Destination
Port are used in this step.</t>
<t>Prepend an IPv4 header. Use the extracted Source IP address,
Destination IP address, and Protocol to build the IPv4 header.</t>
</list><?rfc subcompact="no" ?></t>
</section>
</section>
<section anchor="cc" title="A More Compact LISP Encapsulation Flavor">
<t>A more compact LISP encapsulation scheme can be considered if the
following conditions are met:<?rfc subcompact="yes" ?></t>
<t><list style="symbols">
<t>Compatibility with "u" byte is not required.</t>
<t>The origin "Source Port" number is copied into the UDP header of
the encapsulated packet, and vice versa.</t>
<t>The LISP shim is split into two parts: 4 bytes that are placed
right after the UDP header while "Instance ID/Locator-Status-Bits"
are encoded in the last 32 bits of the source IPv4-embedded IPv6
RLOC.</t>
</list></t>
<t><?rfc subcompact="no" ?>This alternate proposal leads to a 4-byte
overhead when transporting IPv4-over-IPv6 LISP packets for both TCP
(<xref target="ctcp2"></xref>) and UDP (<xref
target="cudp2"></xref>).</t>
<t><figure anchor="ctcp2"
title="More Compacted LISP Header Format (TCP Case)">
<artwork><![CDATA[ 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ |Version| Traffic Class | Flow Label |
/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Payload Length | Next Header=17| Hop Limit |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
| | | |
I + Source Routing Locator (64 bits) + |
P | | S
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ R
H | Source EID | C
E +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
A | Instance ID/Locator-Status-Bits | |
D +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
E | | |
R + Destination Routing Locator (64 bits) + |
| | | D
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ S
| | Destination EID | T
\ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
\ | 00000000 |(Inner)Protocol|(Inner)Destination Port | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
/ | Source Port = Inner Src Port | Dest Port = 4341 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
L \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
I | |N|L|E|V|I|flg|C| Nonce/Map-Version |
S / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
P | Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Acknowledgment Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data | |U|A|P|R|S|F| |
| Offset| Reserved |R|C|S|S|Y|I| Window |
| | |G|K|H|T|N|N| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (Optional) Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]></artwork>
</figure></t>
<t><figure anchor="cudp2"
title="More Compacted LISP Header Format (UDP Case)">
<artwork><![CDATA[ 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ |Version| Traffic Class | Flow Label |
/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Payload Length | Next Header=17| Hop Limit |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
| | | |
I + Source Routing Locator (64 bits) + |
P | | S
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ R
H | Source EID | C
E +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
A | Instance ID/Locator-Status-Bits | |
D +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
E | | |
R + Destination Routing Locator (64 bits) + |
| | | D
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ S
| | Destination EID | T
\ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
\ | 00000000 |(Inner)Protocol|(Inner)Destination Port | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
/ | Source Port = Inner Src Port | Dest Port = 4341 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
L \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
I | |N|L|E|V|I|flg|C| Nonce/Map-Version |
S / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
P ]]></artwork>
</figure></t>
<section title="LISP Encapsulation with the More Compact Header Form">
<t>Upon receipt of an IPv4 packet that needs to be forwarded over a
LISP-enabled infrastructure, the ITR proceeds as follows:<?rfc subcompact="yes" ?></t>
<section title="UDP Packets">
<t><list style="symbols">
<t>Retrieve the destination/source RLOC IPv6 prefix.</t>
<t>Concatenate the source RLOC IPv6 prefix, the source IPv4
address, and the "Instance ID/Locator-Status-Bits" to form the
source IPv6 address as shown in <xref
target="cudp2"></xref>.</t>
<t>Concatenate the destination RLOC IPv6 prefix, the destination
IPv4 address, a null octet, the "Protocol" as indicated in the
IP header, and the destination port number to form the
destination IPv6 address as shown in <xref
target="cudp2"></xref>, for non-fragmented packets and fragments
that convey a transport header.</t>
<t>Remove the IPv4 header.</t>
<t>Set the destination port number of the UDP header to
4341.</t>
<t>Insert the LISP header right after the UDP header.</t>
<t>Prepend the IPv6 header.</t>
</list></t>
</section>
<section title="TCP Packets">
<t><list style="symbols">
<t>Retrieve the destination/source RLOC IPv6 prefix.</t>
<t>Concatenate the source RLOC IPv6 prefix, the source IPv4
address, and the "Instance ID/Locator-Status-Bits" to form the
source IPv6 address as shown in <xref
target="ctcp2"></xref>.</t>
<t>Concatenate the destination RLOC IPv6 prefix, the destination
IPv4 address, a null octet, the "Protocol" as indicated in the
IP header, and the destination port number to form the
destination IPv6 address as shown in <xref
target="ctcp2"></xref>, for non-fragmented packets and fragments
that convey a transport header.</t>
<t>Remove the IPv4 header.</t>
<t>Remove the first 4 bytes and the 4 bytes right after the
"window" field of the TCP header.</t>
<t>Prepend the LISP header.</t>
<t>Prepend the UDP header. Set to the source port number to the
same port indicated in the original TCP header. Set the
destination port number of the UDP header to 4341.</t>
<t>Prepend an IPv6 header.</t>
</list></t>
</section>
<section title="Fragments">
<t><list style="symbols">
<t>Retrieve the destination/source RLOC IPv6 prefix.</t>
<t>Concatenate the source RLOC IPv6 prefix, the source IPv4
address, and the "Instance ID/Locator-Status-Bits" to form the
source IPv6 address as shown in <xref
target="cudp2"></xref>.</t>
<t>Concatenate the destination RLOC IPv6 prefix, the destination
IPv4 address, a non-null octet, the "Protocol" as indicated in
the IP header, and a null octet padding to form the destination
IPv6 address.</t>
<t>Remove the IPv4 header.</t>
<t>Insert the LISP header.</t>
<t>Insert the UDP header with a destination port number set to
4341.</t>
<t>Prepend the IPv6 header.</t>
</list><?rfc subcompact="no" ?></t>
</section>
</section>
<section title="LISP Decapsulation with the More Compact LISP Header">
<t>Upon receipt of a LISP packet with the C-bit set, the ETR proceeds
as follows to extract the inner IP packets: (<xref
target="cudp2"></xref> for UDP and <xref target="ctcp2"></xref> for
TCP). Like in <xref target="comp"></xref>, the UDP checksum setting
and validation of LISP-encapsulated packets MUST follow the guidelines
documented in Section 5.3 of <xref target="RFC6830"></xref>.<?rfc subcompact="yes" ?></t>
<section anchor="eudp2" title="Build an IPv4/UDP Header">
<t><list style="symbols">
<t>Check whether the destination IPv6 address matches an RLOC
prefix owned by the xTR.</t>
<t>Extract the Source EID that is encoded in positions 64 to 95
of the Source IPv6 address.</t>
<t>Extract the "Instance ID/Locator-Status-Bits" field that is
encoded in positions 96 to 127 of the Source IPv6 address.</t>
<t>Extract the Destination EID that is encoded in positions 64
to 95 of the Destination IPv6 address.</t>
<t>Extract the "Protocol" that is encoded in positions 104 to
111 of the Destination IPv6 address.</t>
<t>Extract the Destination Port that is encoded in positions 112
to 127 of the Destination IPv6 address if the octet in positions
96 to 103 is not null.</t>
<t>Remove the IPv6 header, the UDP header, and the LISP
header.</t>
<t>For non-fragmented packets and fragments that convey a
transport header, use the extracted Source Port and Destination
Port to build the UDP header. Prepend the new UDP header.</t>
<t>Use the extracted Source IPv4 address, Destination IPv4
address, and Protocol to build the IPv4 header. Prepend the new
IPv4 header.</t>
</list></t>
</section>
<section anchor="etcp2" title="Build an IPv4/TCP Header">
<t><list style="symbols">
<t>Check whether the destination IPv6 address matches an RLOC
prefix owned by the xTR.</t>
<t>Extract the Source EID that is encoded in positions 64 to 95
of the Source IPv6 address.</t>
<t>Extract the "Instance ID/Locator-Status-Bits" field that is
encoded in positions 96 to 127 of the Source IPv6 address.</t>
<t>Extract the Destination EID that is encoded in positions 64
to 95 of the Destination IPv6 address.</t>
<t>Extract the "Protocol" that is encoded in positions 104 to
111 of the Destination IPv6 address.</t>
<t>Extract the Destination Port that is encoded in positions 112
to 127 of the Destination IPv6 address if the octet in positions
96 to 103 is not null.</t>
<t>Check whether the destination IPv6 address matches an RLOC
prefix owned by the xTR.</t>
<t>Remove the IPv6 header, UDP header, and LISP header.</t>
<t>For non-fragmented packets and fragments that convey a
transport header, prepend 4 bytes with the source/destination
port number and insert 4 bytes right after the "window" field to
build a proper TCP header. The extracted Source Port and
Destination Port are used during this step.</t>
<t>Prepend an IPv4 header. Use the extracted Source IP address,
Destination IP address, and Protocol to build the IPv4
header.</t>
</list><?rfc subcompact="no" ?></t>
</section>
</section>
</section>
<section title="Discussion">
<t>The proposed compact headers are experimental. What primarily
motivates this specification is the need to assess its technical
feasibility thanks to an existing LISP-enabled platform. Experiments
will help evaluate the gain brought by using such compact headers
compared to base LISP encapsulation scheme in typical IPv6 migration
scenarios</t>
<t>The proposed compact encapsulation schemes guarantee a functional
parity with the base LISP specification, given that the signalling
carried in a LISP packet remains usable.</t>
<t>This specification does not include any capability checks to ensure
that remote xTRs support the proposed header encoding. Particularly,
deployability considerations in multi-domain LISP environments are not
detailed in this document.</t>
<t>This specification assumes that a configuration parameter should be
supported by LISP implementations to tweak the encapsulation scheme to
be used.</t>
<t>The handling of fragmented packets by an ETR follows the same steps
as in <xref target="comp"></xref> except that, for the fragments that do
not carry the source/destination port numbers, a non-null octet of the
"suffix" defined <xref target="emb"></xref> is used to signal that the
LISP-encapsulated packet is a fragment that does not convey
transport-related information.</t>
</section>
<section title="Security Considerations">
<t>This document does not introduce any additional security issues other
than those discussed in Section 12 of<xref target="RFC6830">
</xref>.</t>
</section>
<section title="IANA Considerations">
<t>No request to IANA.</t>
</section>
<section title="Acknowledgments">
<t>This work is partly funded by ANR LISP-Lab project
#ANR-13-INFR-009-X.</t>
</section>
</middle>
<back>
<references title="Normative references">
<?rfc include='reference.RFC.6830'
?>
<?rfc include='reference.RFC.2119'?>
<?rfc include='reference.RFC.6052'?>
<?rfc include='reference.RFC.0793'?>
<?rfc include='reference.RFC.0768'?>
</references>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-24 05:27:24 |