INTERNET-DRAFT T. Herbert
Intended Status: Experimental Google
Expires: July 2015 January 20, 2015
Identifier-locator addressing for network virtualization
draft-herbert-nvo3-ila-00
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Abstract
This specification describes identifier-locator addressing (ILA) in
IPv6 for network virtualization. Identifier-locator addressing
differentiates between location and identity of a network node. Part
of an address expresses the immutable identity of the node, and
another part indicates the location of the node which can be dynamic.
In the context of virtualization, a virtual address serves as an
identifier and the address of the host where the associated tenant
system currently resides is a locator.
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Address formats . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 ILA format . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Identifier format . . . . . . . . . . . . . . . . . . . . . 6
2.3 Identifier types . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Interface identifiers . . . . . . . . . . . . . . . . . . . 6
2.5 Locally unique identifiers . . . . . . . . . . . . . . . . . 7
2.6 Virtual networking identifiers for IPv4 . . . . . . . . . . 7
2.7 Virtual networking identifiers for IPv6 . . . . . . . . . . 7
2.7.1 Virtual networking identifiers for IPv6 unicast . . . . 7
2.7.2 Virtual networking identifiers for IPv6 multicast . . . 8
2.8 Standard identifier representation addresses . . . . . . . . 9
2.8.1 SIR for locally unique identifiers . . . . . . . . . . . 10
2.8.2 SIR for virtual addresses . . . . . . . . . . . . . . . 10
2.9 Locators . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1 Identifier to locator mapping . . . . . . . . . . . . . . . 12
3.2 Address translations . . . . . . . . . . . . . . . . . . . . 12
3.2.1 SIR to ILA address translation . . . . . . . . . . . . . 12
3.2.2 ILA to SIR address translation . . . . . . . . . . . . . 13
3.3 Virtual networking operation . . . . . . . . . . . . . . . . 13
3.3.1 Crossing virtual networks . . . . . . . . . . . . . . . 14
3.3.2 IPv4/IPv6 protocol translation . . . . . . . . . . . . . 14
3.4 One sided ILA . . . . . . . . . . . . . . . . . . . . . . . 14
3.5 Checksum handling . . . . . . . . . . . . . . . . . . . . . 14
3.5.1 Transmit checksum . . . . . . . . . . . . . . . . . . . 14
3.5.2 Receive checksum . . . . . . . . . . . . . . . . . . . . 15
3.6 Address selection . . . . . . . . . . . . . . . . . . . . . 15
4. Communication scenarios . . . . . . . . . . . . . . . . . . . . 15
4.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 15
4.2 Identifier objects . . . . . . . . . . . . . . . . . . . . . 16
4.2 Reference network for scenarios . . . . . . . . . . . . . . 17
4.3 Scenario 1: Task to task . . . . . . . . . . . . . . . . . . 18
4.4 Scenario 2: Task to Internet . . . . . . . . . . . . . . . . 18
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4.5 Scenario 3: Internet to task . . . . . . . . . . . . . . . . 18
4.6 Scenario 4: TS to service task . . . . . . . . . . . . . . . 19
4.7 Scenario 5: Task to TS . . . . . . . . . . . . . . . . . . . 19
4.8 Scenario 6: TS to Internet . . . . . . . . . . . . . . . . . 20
4.9 Scenario 7: Internet to TS . . . . . . . . . . . . . . . . . 20
4.10 Scenario 8: IPv4 TS to service . . . . . . . . . . . . . . 20
4.11 TS to TS in the same virtual network . . . . . . . . . . . 21
4.11.1 Scenario 9: TS to TS in same VN using IPV6 . . . . . . 21
4.11.2 Scenario 10: TS to TS in same VN using IPv4 . . . . . . 21
4.12 TS to TS in a different virtual network . . . . . . . . . . 21
4.12.1 Scenario 11: TS to TS in a different VN using IPV6 . . 22
4.12.2 Scenario 12: TS to TS in a different VN using IPv4 . . 22
4.12.3 Scenario 13: IPv4 TS to IPv6 TS in different VNs . . . 22
5. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.1 Data center virtualization . . . . . . . . . . . . . . . . . 23
5.1.1 Job scheduling . . . . . . . . . . . . . . . . . . . . . 23
5.1.1 Address migration . . . . . . . . . . . . . . . . . . . 24
5.1.2 Connection migration . . . . . . . . . . . . . . . . . . 24
5.1.3 Task identifier generation . . . . . . . . . . . . . . . 25
5.1.3.1 Gobally unique identifiers method . . . . . . . . . 25
5.1.3.2 Universally Unique Identifiers method . . . . . . . 25
5.1.3.3 Duplicate identifier detection . . . . . . . . . . . 26
5.2 Multi-tenant virtualization . . . . . . . . . . . . . . . . 26
5.2.1 IPv6 over IPv6 network virtualization . . . . . . . . . 27
5.2.2 IPv4 over IPv6 network virtualization . . . . . . . . . 28
6 Security Considerations . . . . . . . . . . . . . . . . . . . . 29
7 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 29
8 References . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.1 Normative References . . . . . . . . . . . . . . . . . . . 29
8.2 Informative References . . . . . . . . . . . . . . . . . . 30
9 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 31
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1 Introduction
This document describes the data path, address formats, and expected
use cases of identifier-locator addressing in IPv6 ([RFC2460]). The
Identifier-Locator Network Protocol (ILNP) ([RFC6740], [RFC6741])
defines a protocol and operations model for identifier-locator
addressing in IPv6. Many concepts here are taken from ILNP, however
there are some differences in the context of network virtualization--
for instance we assume that a centralized control plane will be
implemented that provides mappings of identifiers to locators.
In identifier-locator addressing, an IPv6 address is split into a
locator and an identifier component. The locator indicates the
physical location in the network for a node, and the identifier
indicates the node's identity which is the logical or virtual
endpoint in communications. Locators are routable within a network,
but identifiers typically are not. An application addresses a
destination by identifier. Identifiers are mapped to locators for
transit in the network. The on-the-wire address is composed of a
locator and an identifier: the locator is sufficient to route the
packet to a physical host, and the identifier allows the receiving
host to forward the packet to the addressed application.
Identifiers are not statically bound to a host on the network, and in
fact their binding (or location) may change. This is the basis for
network virtualization and address migration. An identifier is mapped
to a locator at any given time, and a set of identifier to locator
mappings is propagated throughout a network to allow communications.
The mappings are kept synchronized so that if an identifier migrates
to a new physical host, its identifier to locator mapping is updated.
In network virtualization, an identifier may further be split into a
virtual network identifier and virtual host address. With identifier-
locator addressing network virtualization can be implemented in an
IPv6 network without any additional encapsulation headers. Packets
sent with identifier-locator addresses look like plain unencapsulated
packets (e.g. TCP/IP packets). This "encapsulation" is transparent to
the network, so protocol specific mechanisms in network hardware work
seamlessly. These mechanisms include hash calculation for ECMP, NIC
large segment offload, checksum offload, etc.
2 Address formats
This section describes the address formats associated with
identifier-locator addressing in network virtualization.
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2.1 ILA format
As described in ILNP ([RFC6741]) an IPv6 address may be encoded to
hold a locator and identifier where each occupies 64 bits. In ILA,
the upper three bits of the identifier indicate an identifier type.
/* IPv6 canonical address format */
| 64 bits | 64 bits |
+--------------------------------+-------------------------------+
| IPv6 Unicast Routing Prefix | Interface Identifier |
+--------------------------------+-------------------------------+
/* ILA for IPv6 */
| 64 bits |3 bits| 61 bits |
+--------------------------------+-------------------------------+
| Locator | Type | Identifier |
+----------------------------------------------------------------+
An IPv6 header with ILA addresses would then have the format:
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 | Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Locator |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type | Source Identifier |
+-+-+-+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Locator |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type | Destination Identifier |
+-+-+-+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note that there is no requirement that both the source and
destination are identifier-locator addresses.
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2.2 Identifier format
An ILA identifier includes a three bit type field and sixy-one bits
for an identfier value.
/* Identifier format for ILA */
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type| Identifier |
+-+-+-+ |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: Type of the identifier (see below).
o Identifier: Identifier value.
2.3 Identifier types
Defined identifier types are:
0: interface identifier
1: locally unique identifier
2: virtual networking identifier for IPv4 address
3: virtual networking identifier for IPv6 unicast address
4: virtual networking identifier for IPv6 multicast address
5-7: Reserved
2.4 Interface identifiers
The interface identifier type indicates a plain local scope interface
identifier. When this type is used the address is a normal IPv6
address without identifier-locator semantics.
/* Local scope interface identifier */
| 64 bits |3 bits| 61 bits |
+----------------------------+------+---------------------------+
| Address1 | 0x0 | Address2 |
+---------------------------------------------------------------+
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2.5 Locally unique identifiers
Locally unique identifiers (LUI) can be created for various
addressable nodes within a network. These identifiers are in a flat
61 bit space and must be unique within a domain (unique within a site
for instance). To simplify administration, hierarchical allocation of
locally unique identifiers may be done.
/* ILA with locally unique identifiers */
| 64 bits |3 bits| 61 bits |
+----------------------------+------+---------------------------+
| Locator | 0x1 | Locally unique ident. |
+---------------------------------------------------------------+
2.6 Virtual networking identifiers for IPv4
This type defines a format for encoding an IPv4 virtual address and
virtual network identifier within an identifier.
/* ILA for IPv4 virtual networking */
| 64 bits |3 bits| 29 bits | 32 bits |
+----------------------------+------+---------------+-----------+
| Locator | 0x2 | VNID | VADDR |
+---------------------------------------------------------------+
VNID is a virtual network identifier and VADDR is a virtual address
within the virtual network indicated by the VNID. The VADDR can be an
IPv4 unicast or multicast address, and may often be in a private
address space (i.e. [RFC1918]) used in the virtual network.
2.7 Virtual networking identifiers for IPv6
A virtual network identifier and an IPv6 virtual host address (tenant
visible address) can be encoded within an identifier. Encoding the
virtual host address involves mapping the 128 bit address into a
sixy-one bit identifier. Different encodings are used for unicast and
multicast addresses.
2.7.1 Virtual networking identifiers for IPv6 unicast
In this format, the virtual network identifier and virtual IPv6
unicast address are encoded within an identifier. To facilitate
encoding of virtual addresses, there is a unique mapping between a
VNID and a 96 bit prefix.
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/* IPv6 unicast encoding with VNID in ILA */
| 64 bits |3 bits| 29 bits | 32 bits |
+------------------------------+------+--------------+-----------+
| Locator | 0x3 | VNID | VADDR6L |
+----------------------------------------------------------------+
VADDR6L contains the low order 32 bits of the IPv6 virtual address.
The upper 96 bits of the virtual address inferred from the VNID to
prefix mapping.
The figure below illustrates encoding a tenant IPv6 virtual unicast
address into a ILA address.
/* IPv6 virtual address seen by tenant */
+----------------------------------------------+-----------------+
| Tenant prefix | VADDR6L |
+-----------------------+-------------------------------+--------+
| |
+-prefix to VNID-+ |
| |
v v
+---------------------------+------+-----------+-----------------+
| Locator | 0x3 | VNID | VADDR6L |
+----------------------------------------------------------------+
/* Encoded IPv6 virtual address with VNID in ILA */
This encoding is reversible, given an ILA address, the virtual
address visible to the tenant can be deduced:
/* ILA encoded virtual networking address */
+---------------------------+------+-----------+-----------------+
| Locator | 0x3 | VNID | VADDR6L |
+----------------------------------------+-----------------------+
| |
+-VNID to prefix-+ |
| |
v v
+----------------------------------------------+-----------------+
| Tenant prefix | VADDR6L |
+----------------------------------------------------------------+
/* IPv6 virtual address seen by tenant */
2.7.2 Virtual networking identifiers for IPv6 multicast
In this format, a virtual network identifier and virtual IPv6
multicast address are encoded within an identifier.
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/* IPv6 multicast address with VNID encoding in ILA */
| 64 bits |3 bits| 29 bits |4 bits| 28 bits |
+--------------------------+------+------------------------------+
| Locator | 0x4 | VNID |Scope | MADDR6L |
+----------------------------------------------------------------+
This format encodes a multicast IPv6 address in an identifier. The
scope indicates multicast address scope as defined in [RFC7346].
MADDR6L is the low order 28 bits of the multicast address. The full
multicast address is thus:
ff0<Scope>::0<MADDRL6 high 12 bits>:<MADDRL6 low 16 bits>
This encoding permits encoding of multicast addresses of the form:
ff0X::0 to ff0X::0fff:ffff
The figure below illustrates encoding a tenant IPv6 virtual multicast
address into an ILA address.
/* IPv6 multicast address */
| 12 bits | 4 bits| 84 bits | 28 bits |
+---------+-------+-----------------------------------+----------+
| 0xfff | Scope | 0's | MADDR6L |
+-------------+---------------------------------------------+----+
| |
+------------------------------------+ |
| |
v v
+--------------------------+------+------------------------------+
| Locator | 0x4 | VNID |Scope | MADDR6L |
+----------------------------------------------------------------+
/* IPv6 multicast address with VNID encoding in ILA */
2.8 Standard identifier representation addresses
An identifier serves as the external representation of a network
node. For instance, an identifier may refer to a specific host,
virtual machine, or tenant system. When a host initiates a connection
or sends a packet, it uses the identifier to indicate the peer
endpoint of the communication. The endpoints of an established
connection context also nominally refer to identifiers. It is only
when the packet is actually being sent over a network that the
locator for the identifier needs to be resolved.
In order to maintain compatibility with existing networking stacks
and applications, identifiers are encoded in IPv6 addresses using a
standard identifier representation (SIR) address. A SIR address is a
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combination of a prefix which occupies what would be the locator
portion of an ILA address, and the identifier in its usual location.
/* SIR address in IPv6 */
| 64 bits | 64 bits |
+--------------------------------+-------------------------------+
| SIR prefix | Identifier |
+----------------------------------------------------------------+
A SIR prefix may be may be site-local, or globally routable. A
globally routable SIR prefix allows connectivity between hosts on the
Internet and ILA endpoints. A gateway between a site's network and
the Internet can translate between SIR prefix and locator for an
identifier. A network may have multiple SIR prefixes, and may also
allow tenant specific SIR prefixes in network virtualization.
The standard identifier representation can be used as the externally
visible address for an node. This can used throughout the network,
returned in DNS AAAA records ([RFC3363]), used in logging, etc. An
application can use a SIR address without knowledge that it encodes
an identifier.
2.8.1 SIR for locally unique identifiers
The SIR address for a locally unique identifier has format:
/* SIR address with locally unique identifiers */
| 64 bits |3 bits| 61 bits |
+--------------------------------+-------------------------------+
| SIR prefix | 0x1 | Locally unique ident. |
+----------------------------------------------------------------+
When using ILA with locally unique identifiers a flow tuple logically
has the form:
(source identifier, source port,
destination identifier, destination port)
Using standard identifier representation the flow is then represented
with IPv6 addresses:
(source SIR address, source port,
destination SIR address, destination port)
2.8.2 SIR for virtual addresses
An ILA virtual address may be encoded using the standard identifier
representation. For example, the SIR address for an IPv6 virtual
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address may be:
/* SIR with IPv6 virtual network encoding */
| 64 bits |3 bits| 29 bits | 32 bits |
+------------------------------+------+-------------+------------+
| Tenant's SIR prefix | 0x3 | VNID | VADDRL6 |
+----------------------------------------------------------------+
In a tenant system, a flow tuple would have the form:
(local VADDR, local port, remote VADDR, remote port)
After translating packets for the flow into ILA, the flow would be
identified on-the-wire as:
((local VNID, local VADDR), local port,
(remote VNID, remote VADDR), remote port
A tenant may communicate with a peer in the network which is not in
its virtual network, for instance to reach a network service (see
below). In this case the flow tuple at the peer may be:
(local SIR address, local port,
remote SIR address, remote port)
In this example, the remote SIR address is a SIR address for a
virtual networking identifier, however from peer's connectivity
perspective this is not distinguishable from a SIR address with a
locally unique identifier or even a non-ILA address.
2.9 Locators
Locators are routable network address prefixes that address physical
hosts within the network. They may be assigned from a global address
block [RFC3587], or be based on unique local IPv6 unicast addresses
as described in [RFC4193].
/* ILA with a global unicast locator */
|3 bits| N bits | M bits | 61-N-M | 64 bits |
+------+-------------+---------+---------------------------------+
| 001 | Global prefix | Subnet | Host | Identifier |
+------+---------------+---------+--------+----------------------+
/* ILA with a unique local IPv6 unicast locator */
| 7 bits |1| 40 bits | 16 bits | 64 bits |
+--------+-+------------+-----------+----------------------------+
| FC00 |L| Global ID | Host | Identifier |
+--------+-+------------+-----------+----------------------------+
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3 Operation
This section describes operation methods for using identifier-locator
addressing with network virtualization.
3.1 Identifier to locator mapping
An application initiates a communication or flow using a SIR address
or virtual address for a destination. In order to send a packet on
the network, the destination identifier is mapped to a locator. The
mappings are not expected to change frequently, so it is likely that
locator mappings can be cached in the flow contexts.
Identifier to locator mapping is nearly identical to the mechanism
needed in virtual networking to map a virtual network and virtual
host address to a physical host. These mechanisms should leverage a
common solution.
The mechanisms of propagating and maintaining identifier to locator
mappings are outside the scope of this document.
3.2 Address translations
With ILA, address translation is performed to convert SIR addresses
to ILA addresses, and ILA addresses to SIR addresses. Translation may
be done on either the source or destination address of a packet.
Translation is stateless and is done per IPv6-to-IPv6 Network Prefix
Translation (NPTv6) ([RFC6296]).
3.2.1 SIR to ILA address translation
When transmitting a packet, the locator for both the source and
destination ILA addresses might need to be set before packet is sent
on the wire. In the case that packet was created using a standard
identifier representation, the SIR prefix is overridden with a
locator. Since this operation is potentially done for every packet
the process should be very efficient. Presumably, a host will
maintain a cache of identifier locator mappings with a fast lookup
function. If there is a connection state associated with the
communication, the locator information may be cached with the
connection state to obviate the need to perform a lookup per packet.
The typical steps to transmit a packet using ILA are:
1) Stack creates a packet with source address set to SIR address
for the local identity, and the destination address is set to
the SIR address for the peer. The peer SIR address may have been
discovered through DNS or other means.
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2) Stack overwrites the SIR prefix in the source address with an
appropriate locator for the local host.
3) Stack overwrites the SIR prefix in the destination address with
a locator for the peer. This locator is discovered by a lookup
in the locator to identifier mappings.
4) If a transport checksum includes a pseudo header that covered
the original addresses, the checksum needs to be updated. This
should be akin to the checksum update needed in address
translation for NAT ([RFC6296]).
5) Packet is sent on the wire. The network routes the packet to the
host indicated by the locator.
3.2.2 ILA to SIR address translation
Upon reception, the identifier is used to match a valid address on
the host or a connection context. In order to avoid having networking
stack operate on a new address type, identifier-locator addresses may
be translated to standard identifier representation addresses by
overwriting the locator in the address with a SIR prefix.
Receive processing may be:
1) Packet is received, the destination locator matches an interface
address prefix on the host.
2) A lookup is performed on the destination identifier to match to
a local identifier. If the lookup is address based, the SIR
address can be created for the destination (overwrite locator
with a SIR prefix).
3) Perform any checks as necessary. Validate locators, identifiers,
and check that packet is not illegitimately crossing virtual
networks (see below).
4) Forward packet to application processing. If necessary, the
addresses in the packet can be converted to SIR addresses in
place. Changing the addresses may also entail updating the
checksum to reflect that (again similar to a NAT translation).
3.3 Virtual networking operation
When using ILA with virtual networking identifiers, address
translation is performed to convert tenant virtual network and
virtual addresses to ILA addresses, and ILA addresses back to a
virtual network and tenant's virtual addresses. Address translation
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is performed similar to the SIR translation cases described above.
A packet with virtual networking ILA addresses must be verified on
reception. By default, the virtual network identifiers in the source
and destination addresses must match or the packet is dropped. This
would include the case that one address is using ILA with virtual
network identifier and the other is not.
3.3.1 Crossing virtual networks
With explicit configuration, virtual network hosts may communicate
directly with virtual hosts in another virtual network. This might be
done to allow services in one virtual network to be accessed from
another (by prior agreement between tenants). In this case, the
virtual networking identifiers in the source and destination
addresses won't match. This does require that identifiers are unique
in a shared space.
3.3.2 IPv4/IPv6 protocol translation
An IPv4 tenant may send a packet that is converted to an IPv6 packet
with ILA addresses having IPv4 virtual networking identifiers.
Similarly, an IPv6 packet with ILA addresses may be converted to an
IPv4 packet to be received by an IPv4-only tenant. These are
IPv4/IPv6 stateless protocol translations as described in [RFC6144]
and [RFC6145].
3.4 One sided ILA
It is not required that ILA be used for both and destination
addresses. For instance a statically addressed server may provide
service to virtual hosts or migratable jobs. Note that even though
the server's address is static, locators for its ILA clients may
change so the server will need identifier to locator mappings.
3.5 Checksum handling
TCP and UDP checksum includes a pseudo checksum that covers the IP
addresses in a packet. In the case of identifier-locator addressing
the checksum must include the actual addresses set in the packet on
the wire. So when creating a checksum for transmit, or verifying a
checksum on receive, identifier-locator addressing must be taken into
account.
3.5.1 Transmit checksum
If the source and destination locators are available when the
transport checksum is being set, these can be used to calculate the
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pseudo checksum for the packet. This might be applicable in cases
where locator information is cached within the context for a
transport connection.
If the locators are set after the transport layer processing, the
checksum can be updated following NAT procedures for address
translation.
3.5.2 Receive checksum
Similar to the transmit case, if address translation occurs before
transport layer processing the checksum must be adjusted per NAT. An
implementation may verify a transport checksum before converting
addresses to standard identifier representation to potentially
obviate modifying the transport checksum to account for translation.
3.6 Address selection
There may be multiple possibilities for creating either a source or
destination address. A node may be associated with more than one
identifier, and there may be multiple locators for a particular
identifier. The selection of an identifier occurs at flow creation
and must be constant for the duration of the flow. Locator selection
should be done once per flow, however may change (in the case of a
migrating connection it will change). ILA address selection should
follow guidelines in Default Address Selection for Internet Protocol
Version 6 (IPv6) ([RFC6742]).
4. Communication scenarios
This section describes the use of identifier-locator addressing in
several scenarios.
4.1 Terminology
A formal notation for identifier-locator addressing with ILNP is
described in [RFC6740]. We extend this to include for network
virtualization cases.
Basic terms are:
A = IP Address
I = Identifier
L = Locator
LUI = Locally unique identifier
VNI = Virtual network identifier
VA = An IPv4 or IPv6 virtual address
VAX = An IPv6 networking identifier (IPv6 VA mapped to VAX)
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SIR = Prefix for standard identifier representation
EXA = An Internet routable prefix, may be use as a SIR
VNET = IPv6 prefix for a tenant
An ILA IPv6 address is denoted by
L:I
A transport endpoint IPv6 address with a locally unique identifier
with SIR prefix is denoted by
SIR:LUI
A virtual identifier with a virtual network identifier and a virtual
IPv4 address is denoted by
VNI:VA
An ILA IPv6 address with a virtual networking identifier for IPv4
would then be denoted
L:(VNI:VA)
The local and remote address pair in a packet or endpoint is denoted
A,A
An address translation sequence from transport visible addresses to
ILA addresses for transmission on the network and back to transport
endpoint addresses at the receiver has notation:
A,A -> L:I,L:I -> A,A
4.2 Identifier objects
Identifier-locator addressing is broad enough in scope to address may
different types of networking objects within a data center. For
descriptive purposes we classify these objects as tasks or tenant
systems.
A task is a unit of execution that runs in the data center networks.
These do not run in a virtual machine, but typically run in the
native host context perhaps within containers. Task are the execution
mechanism for native jobs in the data center.
A tenant system, or TS, is a unit of execution which runs on behalf
of a tenant in network virtualization. A TS may be implemented as a
virtual machine or possibly using containers mechanisms. In either
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case, a virtual overlay network is implemented on behalf of a tenant,
and isolation between virtual networks is paramount.
A network service is a task that provides some network wide service
such as DNS, remote storage, remote logging, etc. A network service
may be accessed by tenant systems as well as other tasks.
4.2 Reference network for scenarios
The figure below provides an example network topology with ILA
addressing in use. In this example, there are four hosts in the
network with locators L1, L2, L3 , and L4. Three tasks with
identifiers T1, T2, and T3 exist as well as a networking service task
with identifier T4. The identifiers for these tasks may be locally
unique identifiers. There are two virtual networks VNI1 and VNI2, and
four tenant systems addressed as: VA1 and VA2 in VNI1, VA3 and VA4 in
VNI2. The network is connected to the Internet via a gateway.
` .............
. .
+-----------------+ . Internet . +-----------------+
| Host L1 | . . | Host L2 |
| +-------------+ | ............. | +-------------+ |
| | TS VNI1:VA1 | | | | | TS VNI1:VA2 | |
| +-------------+ +---+ +-----+-----+ +---+ +-------------+ |
| +-------------+ | | | Gateway | | | +-------------+ |
| | Task T1 | | | +-----+-----+ | | | TS VNI2:VA3 | |
| +-------------+ | | | | | +-------------+ |
+-----------------+ | ............. | +-----------------+
+-----. Data .-----+
+-----------------+ . Center . +-----------------+
| Host L3 | +-----. Network .---+ | Host L4 |
| +-------------+ | | ............. | | +-------------+ |
| | Task T2 | | | | | | VM VNI2:VA4 | |
| +-------------+ +---+ +-----| +-------------+ |
| +-------------+ | | +-------------+ |
| | Task T3 | | | | Serv. T4 | |
| +-------------+ | | +-------------+ |
+-----------------+ +-----------------+
There are several communications scenario that can be considered:
1) Task to task (service)
2) Task to Internet
3) Internet to task
4) TS to service
5) Task to TS
6) TS to Internet
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7) Internet to TS
8) IPv4 TS to service
9) TS to TS in same virtual network using IPv6
10) TS to TS in same virtual network using IPv4
11) TS to TS in different virtual network using IPv6
12) TS to TS in different virtual network using IPv4
13) IPv4 TS to IPv6 TS in different virtual networks
4.3 Scenario 1: Task to task
The transport endpoints for task to task communication are the SIR
addresses for the tasks. When a packet is sent on the wire, the
locators are set in source and destination addresses of the packet.
On reception the source and destination addresses are converted back
to SIR representations for processing at the transport layer.
If task T1 is communicating with task T2, the ILA translation
sequence would be:
SIR:T1,SIR:T2 -> // Transport endpoints on T1
L1:T1,L3:T2 -> // ILA used on the wire
SIR:T1,SIR:T2 // Received at T2
4.4 Scenario 2: Task to Internet
Communication from a task to the Internet is accomplished through use
of a gateway that translates the internal locator for the task source
to an externally routable prefix.
If task T1 is sending to an address Iaddr on the Internet, the ILA
translation sequence would be:
SIR:T1,Iaddr -> // Transport endpoints at T1
L1:T1,Iaddr -> // On the wire in data center
EXA:T1,Iaddr // In the Internet
EXA is a globally routable prefix usable on the Internet. On egress
from the data center network, a gateway sets EXA in the source
address. If the SIR prefix is globally routable then this may be the
same as EXA.
4.5 Scenario 3: Internet to task
An Internet host transmits packet to a task using an externally
routable prefix and an identifier. The subnet prefix routes the
packet to a gateway for the data center. The gateway translates the
destination to an ILA address.
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If a host on the Internet with address Iaddr is sends a packet to
task T3, the ILA translation sequence would be:
Iaddr,EXA:T3 -> // Transport endpoint at Iaddr
Iaddr,L1:T3 -> // On the wire in data center
Iaddr,SIR:T3 // Received at T3
EXA is a globally routable prefix usable on the Internet. On ingress
into the data center, a gateway overwrites this with a locator. If
the SIR prefix for T3 is globally routable then this may be the same
as EXA.
4.6 Scenario 4: TS to service task
A tenant can communicate with a data center service using the SIR
address of the service. The source address is translated from the
tenant's address and prefix to VNID and VADDR. Locators must be set
properly for transmission.
If TS VA1 is communicating with service task T4, the ILA translation
sequence would be:
VNET:VA1,SIR:T4-> // Transport endpoints in TS
L1:(VNI1:VAX1),L3:T4-> // On the wire
SIR:(VNI1:VAX1),SIR:T4 // Received at T4
VNET is the address prefix for the tenant. Alternatively, the service
may map the tenant's address to its SIR representation to use VNET
for the endpoint:
VNET:VA1,SIR:T4-> // Transport endpoints in TS
L1:(VNI1:VAX1),L3:T4-> // On the wire
VNET:VA1,SIR:T4 // Received at T4
Note that from the service point of view there is no material
difference between a peer that is a tenant system versus a peer that
is a task.
4.7 Scenario 5: Task to TS
A task can communicate with a TS through it's externally visible
address, or by its virtual networking identifier and virtual address.
If task T2 is communicating with TS VA4, the ILA translation sequence
would be:
SIR:T2,SIR:(VNI2:VA4) -> // Transport endpoints at T2
L3:T2,L4:(VNI2:VA4) -> // On the wire
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SIR:T2,VNET:VA4 // Received at TS
Alternatively, the task can use the VNET prefix to address a TS:
SIR:T2,VNET:VA4 -> // Transport endpoints at T2
L3:T2,L4:(VNI2:VAX4) -> // On the wire
SIR:T2,VNET:VA4 // Received at TS
4.8 Scenario 6: TS to Internet
Communication from a TS to the Internet is accomplished through use
of a gateway that translates the locator in the TS's source address
back to the tenant's prefix. This assumes that the tenant's prefix is
properly routed to the data center network.
If TS VA4 transmits a packet to address Iaddr on the Internet, the
ILA translation sequence would be:
VNET:VA4,Iaddr -> // Transport endpoints at TS
L4:(VNI2:VAX4),Iaddr -> // On the wire in data center
VNET:VA4,Iaddr // On the Internet
4.9 Scenario 7: Internet to TS
An Internet host transmits a packet to a tenant system using an
externally routable tenant prefix and a tenant system identifier. The
prefix routes the packet to a gateway for the data center. The
gateway translates the destination to an ILA address.
If a host on the Internet with address Iaddr is sending to TS VA4,
the ILA translation sequence would be:
Iaddr,VNET:VA4 -> // Endpoint at Iaddr
Iaddr,L4:(VNI2:VAX4) -> // On the wire in data center
Iaddr,VNET:VA4 // Received at TS
4.10 Scenario 8: IPv4 TS to service
A TS that is IPv4-only may communicate with a data center network
service using NAT protocol translation. The network service would
represented as an IPv4 address in the tenant's address space, and
stateless NAT64 should be usable as described in [RFC6145].
If TS VA2 communicates with service task T4, the ILA translation
sequence would be:
VA2,ADDR4 -> // IPv4 endpoints at TS
L2:(VNI1:VA2),L4:T4 -> // On the wire in data center
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SIR:(VNI1:VA2),SIR:T4 // Received at task
VA2 is the IPv4 address in the tenant's virtual network, ADDR4 is an
address in the tenant's address space that maps to the network
service.
The reverse path, task sending to a TS with an IPv4 address, requires
a similar protocol translation.
For service task T4 to communicate with TS VA2, the ILA translation
sequence would be:
SIR:T4,SIR:(VNI1:VA2) -> // Endpoints at T4
L4:T4,L2:(VNI1:VA2) -> // On the wire in data center
ADDR4,VA2 -> // IPv4 endpoint at TS
4.11 TS to TS in the same virtual network
ILA may be used to allow tenants within a virtual network to
communicate without the need for explicit encapsulation headers.
4.11.1 Scenario 9: TS to TS in same VN using IPV6
If TS VA1 sends a packet to TS VA2, the ILA translation sequence
would be:
VNET:VA1,VNET:VA2 -> // Endpoints at VA1
L1:(VNI1:VAX1),L2:(VNI1,VAX2) -> // On the wire
VNET:VA1,VNET:VA2 -> // Received at VA2
4.11.2 Scenario 10: TS to TS in same VN using IPv4
For two tenant systems to communicate using IPv4 and ILA, IPv4/IPv6
protocol translation is done both on the transmit and receive.
If TS VA1 sends an IPv4 packet to TS VA2, the ILA translation
sequence would be:
VA1,VA2 -> // Endpoints at VA1
L1:(VNI1:VA1),L2:(VNI1,VA2) -> // On the wire
VA1,VA2 // Received at VA2
4.12 TS to TS in a different virtual network
A tenant system may be allowed to communicate with another tenant
system in a different virtual network. This should only be allowed
with explicit policy configuration.
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4.12.1 Scenario 11: TS to TS in a different VN using IPV6
For TS VA4 to communicate with TS VA1 using IPv6 the translation
sequence would be:
VNET2:VA4,VNET1:VA1-> // Endpoints at VA4
L4:(VNI2:VA4),L1:(VNI1,VA1)-> // On the wire
SIR:VA4,VNET1:VA1 // Received at VA1
Alternatively, the the VNET prefix can address a TS:
VNET2:VA4,VNET1:VA1-> // Endpoint at VA4
L4:(VNI2:VAX4),L1:(VNI1,VAX1)-> // On the wire
VNET2:VA4,VNET1:VA1 // Received at VA1
4.12.2 Scenario 12: TS to TS in a different VN using IPv4
To allow IPv4 tenant systems in different virtual networks to
communicate with each other, an address representing the peer would
be mapped into the tenant's address space. IPv4/IPv6 protocol
translation is done on transmit and receive.
For TS VA4 to communicate with TS VA1 using IPv4 the translation
sequence may be:
VA4,SADDR1 -> // IPv4 endpoint at VA4
L4:(VNI2:VA4),L1:(VNI1,VA1)-> // On the wire
SADDR4,VA1 // Received at VA1
SADDR1 is the mapped address for VA1 in VA4's address space, and
SADDR4 is the mapped address for VA4 in VA1's address space.
4.12.3 Scenario 13: IPv4 TS to IPv6 TS in different VNs
Communication may also be mixed so that an IPv4 tenants system can
communicate with an IPv6 tenant system in another virtual network.
IPv4/IPv6 protocol translation is done on transmit.
For VM VA4 using IPv4 to communicate with VM VA1 using IPv6 the
translation sequence may be:
VA4,SADDR1 -> // IPv4 endpoint at VA4
L4:(VNI2:VA4),L1:(VNI1,VAX1)-> // On the wire
SIR:VA4,VNET1:VA1 // Received at VA1
Alternatively the task can use the VNET prefix to address a TS:
VA4,SADDR1 -> // IPv4 endpoint at VA4
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L4:(VNI2:VA4),L1:(VNI1,VA1)-> // On the wire
VNET2:VA4,VNET1:VA1 // Received at VA1
SADDR1 is the mapped IPv4 address for VA1 in VA4's address space.
5. Use cases
This section highlights some use cases for identifier-locator
addressing.
5.1 Data center virtualization
A primary motivation for identifier-locator addressing is data center
virtualization. Virtualization within a data center permits
malleability and flexibility in using data center resources. In
particular, identifier-locator addressing virtualizes networking to
allow flexible job scheduling and possibility of live task migration.
5.1.1 Job scheduling
In the usual data center model, jobs are scheduled to run as tasks on
some number of machines. A distributed job scheduler provides the
scheduling which may entail considerable complexity since jobs will
often have a variety of resource constraints. The scheduler takes
these constraints into account while trying to maximize utility of
the data center in terms utilization, cost, latency, etc. Data center
jobs do not typically run in virtual machines (VMs), but may run
within containers. Containers are mechanisms that provide resource
isolation between tasks running on the same host OS. These resources
can include CPU, disk, memory, and networking.
A fundamental problem arises in that once a task for a job is
scheduled on a machine, it often needs to run to completion. If the
scheduler needs to schedule a higher priority job or change resource
allocations, there may be little recourse but to kill tasks and
restart them on a different machine. In killing a task, progress is
lost which results in increased latency and wasted CPU cycles. Some
tasks may checkpoint progress to minimize the amount of progress
lost, but this is not a very transparent or general solution.
An alternative approach is to allow transparent job migration. The
scheduler may migrate running jobs from one machine to another.
Under the orchestration of the job scheduler, the steps to migrate a
job may be:
1) Stop running tasks for the job.
2) Package the run time state of the job. The run time state is
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derived from the containers for the jobs.
3) Send the run time state of the job to the new machine where the
job is to run.
4) Instantiate the job's state on the new machine.
5) Start the tasks for the job continuing from the point at which
it was stopped.
This model similar to virtual machine (VM) migration except that the
run time state is typically much less data-- just task state as
opposed to a full OS image. Task state may be compressed to reduce
latency in migration.
The networking state of interest to migrate are the addresses used by
the task and open transport connections.
5.1.1 Address migration
To allow for task migration, each migratable task is assigned a
unique address which be moved to a new location at task migration.
With identifier-locator addressing, tasks are assigned locally unique
identifiers (see below for assignment techniques). A LUI is combined
with a SIR prefix to give each task its own IPv6 address. To
communicate with a running task, the LUI is mapped to a locator which
is placed in the on-the-wire packet as discussed above. When a task
migrates to a new machine, the identifier to locator mapping for the
task is updated to reflect the change.
5.1.2 Connection migration
When a task and its addresses are migrated between machines, the
disposition of existing TCP connections needs to be considered.
The simplest course of action is to drop TCP connections across a
migration. Since migrations should be relatively rare events, it is
conceivable that TCP connections could be automatically closed in the
network stack during a migration event. If the applications running
are known to handle this gracefully (i.e. reopen dropped connections)
then this may be viable.
For seamless migration, open connections may be migrated between
hosts. Migration of these entails pausing the connection, packaging
connection state and sending to target, instantiating connection
state in the peer stack, and restarting the connection. From the time
the connection is paused to the time it is running again in the new
stack, packets received for the connection should be silently
dropped. For some period of time, the old stack will need to keep a
record of the migrated connection. If it receives a packet, it should
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either silently drop the packet or forward it to the new location.
5.1.3 Task identifier generation
Potentially every task in a data center could be migratable as long
as each task is assigned a unique identifier. Since the identifier is
fifty-nine bits it is conceivable that identifiers could be allocated
using a shared counter or based on a timestamp.
5.1.3.1 Gobally unique identifiers method
For small to moderate sized deployments the technique for creating
locally assigned global identifiers described in [RFC4193] could be
used. In this technique a SHA-1 digest of the time of day in NTP
format and an EUI-64 identifier of the local host is performed. N
bits of the result are used as the globally unique identifier.
The probability that two or more of these IDs will collide can be
approximated using the formula:
P = 1 - exp(-N**2 / 2**(L+1))
where P is the probability of collision, N is the number of
identifiers, and L is the length of an identifier.
The following table shows the probability of a collision for a range
of identifiers using a 61-bit length.
Identifiers Probability of Collision
1000 2.1684*10^-13
10000 2.1684*10^-11
100000 2.1684*10^-09
1000000 2.1684*10^-07
Note that locally unique identifiers may be ephemeral, for instance a
task may only exist for a few seconds. This should be considered when
determining the probability of identifier collision.
5.1.3.2 Universally Unique Identifiers method
For larger deployments, hierarchical allocation may be desired. The
techniques in Universally Unique IDentifier (UUID) URN ([RFC4122])
can be adapted for allocating unique task identifiers in sixty-one
bits. An identifier is split into two components: a registrar prefix
and sub-identifier. The registrar prefix defines an identifier block
which is managed by the same host, the sub-identifier is a unique
value within the registrar block.
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For instance, a task identifier could be created on the initial
running host that runs a task. The identifier could be composed of a
24 bit host identifier followed by a 37 bit timestamp. Assuming that
a host can start up to 100 tasks per second, this allows 43.5 years
before wrap around.
/* Task identifier with host registrar and timestamp */
|3 bits| 24 bits | 37 bits |
+------+-------------------+-------------------------------------+
| 0x1 | Host identifier | Timestamp Identifier |
+----------------------------------------------------------------+
Hierarchical allocation may also be used to support hierarchical
locator lookup.
5.1.3.3 Duplicate identifier detection
As part of implementing the locator to identifier mapping, duplicate
identifier detection may be implemented in a centralized control
plane. A registry of identifiers would be maintained. When a node
creates an identifier it registers the identifier, and when the
identifier is no longer in use (e.g. task completes) the identifier
is unregistered. The control plane should able to detect a
registration attempt for an existing identifier and deny the request.
5.2 Multi-tenant virtualization
Identifier-locator addressing may be used as an alternative to nvo3
encapsulation protocols (such as GUE [GUE]). In multi-tenant
virtualization, overlay networks are established for various tenants
to create virtual networks and a tenant's nodes are assigned virtual
addresses. Virtual networking identifiers are used to encode a
virtual network identifier and a virtual address in an ILA address.
An advantage of identifier-locator addressing is that the overhead of
encapsulation is reduced and use of virtualization can be transparent
to the underlying network. A downside is that some features that use
additional data in an encapsulation aren't available (security option
in GUE for instance [GUESEC]).
Identifier-locator addressing may be appropriate in network
virtualization where the users are trusted, for instance if virtual
networks were assigned to different departments within an enterprise.
Network virtualization in this context provides a means of isolation
of traffic belonging to different departments of a single tenant. If
this isolation is broken and traffic illegitimately crosses between
virtual networks, this is not considered a significant security risk.
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The communication scenarios section above describes communication
within a virtual network, communications with network services, and
communication with hosts on the Internet.
5.2.1 IPv6 over IPv6 network virtualization
In a canonical implementation of overlay networks for network
virtualization, encapsulation headers are used between outer and IP
inner headers which contains a virtual network identifier and
possibly other data. Typical encapsulation of an IPv6 packet using
GUE is illustrated below:
+-------------------------------+
| |
| IPv6 header |
| |
|-------------------------------|
| |
| UDP/GUE Header |
| |
|-------------------------------|
| |
| IPv6 header |
| |
|-------------------------------|
| |
| TCP header |
| |
+-------------------------------+
The addresses in the outer IPv6 header indicate the physical nodes
(source and destination NVEs) in the network. The inner IPv6
addresses are IPv6 addresses within the virtual network specified by
the VNID in the GUE header.
Using ILA eliminates the encapsulation headers and inner IP headers:
+-------------------------------+
| |
| IPv6 header |
| |
|-------------------------------|
| |
| TCP header |
| |
+-------------------------------+
The IPv6 addresses are ILA addresses with virtual networking IPv6
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identifiers. The encoded VNID indicates the virtual network the
address belongs to, and the encoded VADDR provides the low order 32
bits of the virtual address for both source and destination. The
tenant visible upper 96 bits of the IPv6 address is inferred from the
VNID.
If the destination is multicast, the appropriate multicast identifier
can be used in the destination address.
5.2.2 IPv4 over IPv6 network virtualization
The figure below illustrates the protocol headers when encapsulating
a tenant's IPv4 packet using GUE.
+-------------------------------+
| |
| IPv6 header |
| |
|-------------------------------|
| |
| UDP/GUE Header |
| |
|-------------------------------|
| |
| IPv4 header |
| |
|-------------------------------|
| |
| TCP header |
| |
+-------------------------------+
The addresses in the outer IPv6 header indicate the physical nodes
(source and destination NVEs) in the network. The inner IPv4
addresses are in the virtual network specified by the VNID in the GUE
header.
Using ILA eliminates the encapsulation headers and inner IP headers:
+-------------------------------+
| |
| IPv6 header |
| |
|-------------------------------|
| |
| TCP header |
| |
+-------------------------------+
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The IPv6 addresses are ILA addresses with virtual networking IPv4
identifiers. The encoded VNID indicates the virtual network the
addresses belongs to, and the encoded VADDRs provide the IPv4 virtual
addresses for both source and destination. The IPv4 virtual address
are visible to the tenant systems.
6 Security Considerations
Security must be considered when using identifier-locator addressing.
In particular, the risk of address spoofing or address corruption
must be addressed. To classify this risk the set possible
destinations for a packet are classified as trusted or untrusted. The
set of possible destinations includes those that a packet may
inadvertently be sent due to address or header corruption.
If the set of possible destinations are trusted then packet
misdelivery is considered relatively innocuous. This might be the
case in a data center if all nodes were tightly controlled under
single management. Identifier-locator addressing can be used this
case without further additional security.
If the set of possible destinations are untrusted, then packet
misdelivery is considered detrimental. This may be the case that
virtual machines with third party applications and OS are running in
the network. A malicious user may be snooping for misdelivered
packets, or may attempt to spoof addresses. Identifier locator
addressing should be used with stronger security and isolation
mechanisms such as IPsec or GUESEC.
7 IANA Considerations
There are no IANA considerations in this specification.
8 References
8.1 Normative References
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix
Translation", RFC 6296, June 2011.
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[RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version
6 (IPv6)", RFC 6724, September 2012.
8.2 Informative References
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[RFC6740] RJ Atkinson and SN Bhatti, "Identifier-Locator Network
Protocol (ILNP) Architectural Description", RFC 6740,
November 2012.
[RFC6741] RJ Atkinson and SN Bhatti, "Identifier-Locator Network
Protocol (ILNP) Engineering Considerations", RFC 6741,
November 2012.
[RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G.,
and E. Lear, "Address Allocation for Private Internets",
BCP 5, RFC 1918, February 1996.
[RFC3363] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T.
Hain, "Representing Internet Protocol version 6 (IPv6)
Addresses in the Domain Name System (DNS)", RFC 3363,
August 2002.
[RFC3587] Hinden, R., Deering, S., and E. Nordmark, "IPv6 Global
Unicast Address Format", RFC 3587, August 2003.
[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, October 2005.
[RFC6144] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for
IPv4/IPv6 Translation", RFC 6144, April 2011.
[GUE] Herbert, T., and Yong, L., "Generic UDP Encapsulation",
draft-herbert-gue-02, work in progress.
[GUESEC] Yong L., and Herbert, T. "Generic UDP Encapsulation (GUE)
for Secure Transport", draft-hy-gue-4-secure-transport-
00, work in progress
9 Acknowledgments
The authors would like to thank Mark Smith, Lucy Yong, and Erik Kline
for their insightful comments for this draft; Roy Bryant, Lorenzo
Colitti, Mahesh Bandewar, and Erik Kline for their work on defining
Herbert Expires July 2015 [Page 30]
INTERNET DRAFT draft-herbert-nvo3-ila-00 January 20, 2015
and applying ILA.
Authors' Addresses
Tom Herbert
Google
1600 Amphitheatre Parkway
Mountain View, CA
EMail: therbert@google.com
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