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IETF RFC 6788
Last modified on Monday, November 19th, 2012
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Internet Engineering Task Force (IETF) S. Krishnan
Request for Comments: 6788 A. Kavanagh
Category: Standards Track B. Varga
ISSN: 2070-1721 Ericsson
S. Ooghe
Alcatel-Lucent
E. Nordmark
Cisco
November 2012
The Line-Identification Option
 Abstract
In Ethernet-based aggregation networks, several subscriber premises
may be logically connected to the same interface of an Edge Router.
This document proposes a method for the Edge Router to identify the
subscriber premises using the contents of the received Router
Solicitation messages. The applicability is limited to broadband
network deployment scenarios in which multiple user ports are mapped
to the same virtual interface on the Edge Router.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/RFC 6788.
Krishnan, et al. Standards Track PAGE 1 
RFC 6788 Line-ID Option November 2012
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................3
1.1. Terminology ................................................4
1.2. Conventions Used in This Document ..........................6
2. Applicability Statement .........................................6
3. Issues with Identifying the Subscriber Premises in an
N:1 VLAN Model ..................................................7
4. Basic Operation .................................................7
5. AN Behavior .....................................................8
5.1. On Initialization ..........................................8
5.2. On Receiving a Router Solicitation from the End-Device .....8
5.3. On Receiving a Router Advertisement from the Edge Router ...9
5.3.1. Identifying Tunneled Router Advertisements ..........9
5.4. On Detecting a Subscriber Circuit Coming Up ................9
5.5. On Detecting Edge Router Failure ..........................10
5.6. RS Retransmission Algorithm ...............................10
6. Edge Router Behavior ...........................................10
6.1. On Receiving a Tunneled Router Solicitation from the AN ...10
6.2. On Sending a Router Advertisement Towards the End-Device ..10
6.3. Sending Periodic Unsolicited Router Advertisements
Towards the End-Device ....................................11
7. Line-Identification Option (LIO) ...............................12
7.1. Encoding of Line ID .......................................13
8. Garbage Collection of Unused Prefixes ..........................14
9. Interactions with Secure Neighbor Discovery ....................14
10. Acknowledgements ..............................................14
11. Security Considerations .......................................14
12. IANA Considerations ...........................................14
13. References ....................................................15
13.1. Normative References .....................................15
13.2. Informative References ...................................16
Krishnan, et al. Standards Track PAGE 2
RFC 6788 Line-ID Option November 2012
1. Introduction
Digital Subscriber Line (DSL) is a widely deployed access technology
for Broadband Access for Next Generation Networks. While traditional
DSL access networks were Point-to-Point Protocol (PPP) [RFC 1661]
based, some networks are migrating from the traditional PPP access
model into a pure IP-based Ethernet aggregated access environment.
Architectural and topological models of an Ethernet aggregation
network in the context of DSL aggregation are described in [TR101].
+----+ +----+ +----------+
|Host|---| RG |----| |
+----+ +----+ | |
| AN |\
+----+ +----+ | | \
|Host|---| RG |----| | \
+----+ +----+ +----------+ \ +----------+
\ | |
+-------------+ | |
| Aggregation | | Edge |
| Network |-------| Router |
+-------------+ | |
/ | |
+----------+ / +----------+
| | /
+----+ +----+ | | /
|Host|---| RG |----| AN |/
+----+ +----+ | |
| |
+----------+
Figure 1: Broadband Forum Network Architecture
Krishnan, et al. Standards Track PAGE 3
RFC 6788 Line-ID Option November 2012
One of the Ethernet and Gigabit-capable Passive Optical Network
(GPON) aggregation models specified in this document bridges sessions
from multiple user ports behind a DSL Access Node (AN), also referred
to as a Digital Subscriber Line Access Multiplexer (DSLAM), into a
single VLAN in the aggregation network. This is called the N:1 VLAN
allocation model.
+----------+
| |
| |
| AN |\
| | \
| | \ VLANx
+----------+ \ +----------+
\ | |
+-------------+ | |
| Aggregation | VLANx | Edge |
| Network |-------| Router |
+-------------+ | |
/ | |
+----------+ / +----------+
| | / VLANx
| | /
| AN |/
| |
| |
+----------+
Figure 2: n:1 VLAN model
1.1. Terminology
1:1 VLAN A broadband network deployment scenario in
which each user port is mapped to a different
VLAN on the Edge Router. The uniqueness of
the mapping is maintained in the Access Node
and across the aggregation network.
N:1 VLAN A broadband network deployment scenario in
which multiple user ports are mapped to the
same VLAN on the Edge Router. The user ports
may be located in the same or different Access
Nodes.
GPON Gigabit-capable Passive Optical Network is an
optical access network that has been
introduced into the Broadband Forum
architecture in [TR156].
Krishnan, et al. Standards Track PAGE 4
RFC 6788 Line-ID Option November 2012
AN A DSL or a GPON Access Node. The Access Node
terminates the physical layer (e.g., DSL
termination function or GPON termination
function), may physically aggregate other
nodes implementing such functionality, or may
perform both functions at the same time. This
node contains at least one standard Ethernet
interface that serves as its "northbound"
interface into which it aggregates traffic
from several user ports or Ethernet-based
"southbound" interfaces. It does not
implement an IPv6 stack but performs some
limited inspection/modification of IPv6
packets. The IPv6 functions required on the
Access Node are described in Section 5 of
[TR177].
Aggregation Network The part of the network stretching from the
Access Nodes to the Edge Router. In the
context of this document, the aggregation
network is considered to be Ethernet based,
providing standard Ethernet interfaces at the
edges, for connecting the Access Nodes and the
broadband network. It is comprised of
Ethernet switches that provide very limited IP
functionality (e.g., IGMP snooping, Multicast
Listener Discovery (MLD) snooping, etc.).
RG A residential gateway device. It can be a
Layer-3 (routed) device or a Layer-2 (bridged)
device. The residential gateway for Broadband
Forum networks is defined in [TR124].
Edge Router The Edge Router, also known as the Broadband
Network Gateway (BNG), is the first IPv6 hop
for the user. In cases where the RG is
bridged, the BNG acts as the default router
for the hosts behind the RG. In cases where
the RG is routed, the BNG acts as the default
router for the RG itself. This node
implements IPv6 router functionality.
Host A node that implements IPv6 host
functionality.
Krishnan, et al. Standards Track PAGE 5
RFC 6788 Line-ID Option November 2012
End-Device A node that sends Router Solicitations and
processes received Router Advertisements.
When a Layer-3 (L3) RG is used, it is
considered an end-device in the context of
this document. When a Layer-2 (L2) RG is
used, the host behind the RG is considered to
be an end-device in the context of this
document.
1.2. Conventions Used in This Document
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 [RFC 2119].
2. Applicability Statement
The Line-Identification Option (LIO) is intended to be used only for
the N:1 VLAN deployment model. For the other VLAN deployment models,
line identification can be achieved differently. The mechanism
described in this document allows the connection of hosts that only
support IPv6 stateless address auto-configuration to attach to
networks that use the N:1 VLAN deployment model.
When the Dynamic Host Configuration Protocol (DHCP) [RFC 3315] is used
for IPv6 address assignment, it has the side-effect of providing end-
device-initiated reliability as well as inactivity detection. The
reliability is provided by the end-device continuing to retransmit
DHCP messages until it receives a response), and inactivity is
detected by the end-device not renewing its DHCP lease. The "IPv6
Stateless Address Autoconfiguration" protocol [RFC 4862] was not
designed to satisfy such requirements [RSDA]. While this option
improves the reliability of operation in deployments that use Router
Solicitations rather than DHCP, there are some limitations as
specified below.
The mechanism described in this document deals with the loss of
subscriber-originated Router Solicitations (RSes) by initiating RSes
at the AN, which improves robustness over solely relying on the
end-device's few initial retransmissions of RSes.
However, the AN retransmissions imply that some information (e.g.,
the subscriber's MAC address) that was obtained by the Edge Router
from subscriber-originated RSes may no longer be available. For
example, since there is no L2 frame received from the subscriber in
case of an RS sent by an AN, the L2-address information of the
end-device cannot be determined. One piece of L2-address information
currently used in some broadband networks is the MAC address. For
Krishnan, et al. Standards Track PAGE 6
RFC 6788 Line-ID Option November 2012
this reason, the solution described in this document is NOT
RECOMMENDED for networks that require the MAC address of the endpoint
for identification.
There is no indication when a subscriber is no longer active. Thus,
this protocol cannot be used to automatically reclaim resources, such
as prefixes, that are associated with an active subscriber. See
Section 8. Thus, this protocol is NOT RECOMMENDED for networks that
require automatic notification when a subscriber is no longer active.
This mechanism by itself provides no protection against the loss of
RS-induced state in access routers that would lead to loss of IPv6
connectivity for end-devices. Given that regular IPv6 hosts do not
have RS retransmission behavior that would allow automatic recovery
from such a failure, this mechanism SHOULD only be used in
deployments employing N:1 VLANs.
3. Issues with Identifying the Subscriber Premises in an N:1 VLAN Model
In a DSL- or GPON-based fixed broadband network, IPv6 end-devices are
connected to an AN. Today, these end-devices will typically send a
Router Solicitation message to the Edge Router, to which the Edge
Router responds with a Router Advertisement message. The Router
Advertisement typically contains a prefix that the end-devices will
use to automatically configure an IPv6 address. Upon sending the
Router Solicitation message, the node connecting the end-device on
the access circuit, typically an AN, forwards the RS to the Edge
Router upstream over a switched network. In such Ethernet-based
aggregation networks, several subscriber premises may be connected to
the same interface of an Edge Router (e.g., on the same VLAN).
However, the Edge Router requires some information to identify the
end-device on the circuit. To accomplish this, the AN needs to add
line-identification information to the Router Solicitation message
and forward this to the Edge Router. This is analogous to the case
where DHCP is being used, and the line-identification information is
inserted by a DHCP relay agent [RFC 3315]. This document proposes a
method for the Edge Router to identify the subscriber premises using
the contents of the received Router Solicitation messages. Note that
there might be several end-devices located on the same subscriber
premises.
4. Basic Operation
This document uses a mechanism that tunnels Neighbor Discovery (ND)
packets inside another IPv6 packet that uses a destination option
(Line-ID option) to convey line-identification information as
depicted in Figure 3. The use of the Line-ID option in any other
IPv6 datagrams, including untunneled RS and RA messages, is not
Krishnan, et al. Standards Track PAGE 7
RFC 6788 Line-ID Option November 2012
defined by this document. The ND packets are left unmodified inside
the encapsulating IPv6 packet. In particular, the Hop Limit field of
the ND message is not decremented when the packet is being tunneled.
This is because an ND message whose Hop Limit is not 255 will be
discarded by the receiver of such messages, as described in Sections
6.1.1 and 6.1.2 of [RFC 4861].
+----+ +----+ +-----------+
|Host| | AN | |Edge Router|
+----+ +----+ +-----------+
| RS | |
|---------->| |
| | |
| |Tunneled RS(LIO)|
| |--------------->|
| | |
| |Tunneled RA(LIO)|
| |<---------------|
| RA | |
|<----------| |
| | |
Figure 3: Basic Message Flow
5. AN Behavior
5.1. On Initialization
On initialization, the AN MUST join the All-BBF-Access-Nodes
multicast group on all its upstream interfaces towards the Edge
Router.
5.2. On Receiving a Router Solicitation from the End-Device
When an end-device sends out a Router Solicitation, it is received by
the AN. The AN identifies these messages by looking for ICMPv6
messages (IPv6 Next Header value of 58) with ICMPv6 type 133. The AN
intercepts and then tunnels the received Router Solicitation in a
newly created IPv6 datagram with the Line-Identification Option
(LIO). The AN forms a new IPv6 datagram whose payload is the
received Router Solicitation message as described in [RFC 2473],
except that the Hop Limit field of the Router Solicitation message
MUST NOT be decremented. If the AN has an IPv6 address, it MUST use
this address in the Source Address field of the outer IPv6 datagram.
Otherwise, the AN MUST copy the source address from the received
Router Solicitation into the Source Address field of the outer IPv6
datagram. The destination address of the outer IPv6 datagram MUST be
Krishnan, et al. Standards Track PAGE 8
RFC 6788 Line-ID Option November 2012
copied from the destination address of the tunneled RS. The AN MUST
include a destination options header between the outer IPv6 header
and the payload. It MUST insert an LIO destination option and set
the Line ID field of the option to contain the circuit identifier
corresponding to the logical access loop port of the AN from which
the RS was initiated.
5.3. On Receiving a Router Advertisement from the Edge Router
When the Edge Router sends out a tunneled Router Advertisement in
response to the RS, it is received by the AN. If there is an LIO
present, the AN MUST use the line-identification data of the LIO to
identify the subscriber agent circuit of the AN on which the RA
should be sent. The AN MUST then remove the outer IPv6 header of
this tunneled RA and multicast the inner packet (the original RA) on
this specific subscriber circuit.
5.3.1. Identifying Tunneled Router Advertisements
The AN can identify tunneled RAs by installing filters based on the
destination address (All-BBF-Access-Nodes, which is a reserved
link-local scoped multicast address) of the outer packets and the
presence of a destination option header with an LIO destination
option.
5.4. On Detecting a Subscriber Circuit Coming Up
RSes initiated by end-devices as described in Section 5.2 may be lost
due to lack of connectivity between the AN and the end-device. To
ensure that the end-device will receive an RA, the AN needs to
trigger the sending of periodic RAs on the Edge Router. For this
purpose, the AN needs to inform the Edge Router that a subscriber
circuit has come up. Each time the AN detects that a subscriber
circuit has come up, it MUST create a Router Solicitation message as
described in Section 6.3.7 of [RFC 4861]. It MUST use the unspecified
address as the source address of this RS. It MUST then tunnel this
RS towards the Edge Router as described in Section 5.2.
In case there are connectivity issues between the AN and the Edge
Router, the RSes initiated by the AN can be lost. The AN SHOULD
continue retransmitting the Router Solicitations following the
algorithm described in Section 5.6 for a given LIO until it receives
an RA for that specific LIO.
Krishnan, et al. Standards Track PAGE 9
RFC 6788 Line-ID Option November 2012
5.5. On Detecting Edge Router Failure
When the Edge Router reboots and loses state or is replaced by a new
Edge Router, the AN will detect it using connectivity check
mechanisms that are already in place in broadband networks (e.g.,
Bidirectional Forwarding Detection). When such Edge Router failure
is detected, the AN needs to start transmitting RSes for each of its
subscriber circuits that have come up, as described in Section 5.4.
5.6. RS Retransmission Algorithm
The AN SHOULD use the exponential backoff algorithm for retransmits
that is described in Section 14 of [RFC 3315] in order to continuously
retransmit the Router Solicitations for a given LIO until a response
is received for that specific LIO. The AN SHOULD use the following
variables as input to the retransmission algorithm:
Initial retransmission time (IRT) 1 Second
Maximum retransmission time (MRT) 30 Seconds
Maximum retransmission count (MRC) 0
Maximum retransmission duration (MRD) 0
6. Edge Router Behavior
6.1. On Receiving a Tunneled Router Solicitation from the AN
When the Edge Router receives a tunneled Router Solicitation
forwarded by the AN, it needs to check if there is an LIO destination
option present in the outer datagram. The Edge Router can use the
contents of the Line ID field to lookup the addressing information
and policy that need to be applied to the line from which the Router
Solicitation was received. The Edge Router MUST then process the
inner RS message as specified in [RFC 4861].
6.2. On Sending a Router Advertisement Towards the End-Device
When the Edge Router sends out a Router Advertisement in response to
a tunneled RS that included an LIO, it MUST tunnel the Router
Advertisement in a newly created IPv6 datagram with the LIO as
described below. First, the Edge Router creates the Router
Advertisement message as described in Section 6.2.3 of [RFC 4861].
The Edge Router MUST include a Prefix Information option in this RA
that contains the prefix that corresponds to the received LIO. (The
LIO from the received tunneled RS is usually passed on from the Edge
Router to some form of provisioning system that returns the prefix to
be included in the RA. It could e,g., be based on RADIUS.) Then,
the Edge Router forms the new IPv6 datagram whose payload is the
Router Advertisement message, as described in [RFC 2473], except that
Krishnan, et al. Standards Track PAGE 10
RFC 6788 Line-ID Option November 2012
the Hop Limit field of the Router Advertisement message MUST NOT be
decremented. The Edge router MUST use a link-local IPv6 address on
the outgoing interface in the Source Address field of the outer IPv6
datagram. The Edge Router MUST include a destination options header
between the outer IPv6 header and the payload. It MUST insert an LIO
and set the Line ID field of the option to contain the same value as
that of the Line-ID option in the received RS. The IPv6 destination
address of the inner RA MUST be set to the all-nodes multicast
address.
If the Source Address field of the received IPv6 datagram was not the
unspecified address, the Edge Router MUST copy this address into the
Destination Address field of the outer IPv6 datagram sent back
towards the AN. The link-layer destination address of the outer IPv6
datagram containing the outer IPv6 datagram MUST be resolved using
regular Neighbor Discovery procedures.
If the Source Address field of the received IPv6 datagram was the
unspecified address, the destination address of the outer IPv6
datagram MUST be set to the well-known link-local scope
All-BBF-Access-Nodes multicast address (ff02::10). The link-layer
destination address of the tunneled RA MUST be set to the unicast
link-layer address of the AN that sent the tunneled Router
Solicitation that is being responded to.
The Edge Router MUST ensure that it does not transmit tunneled RAs
whose size is larger than the MTU of the link between the Edge Router
and the AN, which would require that the outer IPv6 datagram undergo
fragmentation. This limitation is imposed because the AN may not be
capable of handling the reassembly of such fragmented datagrams.
6.3. Sending Periodic Unsolicited Router Advertisements Towards the
End-Device
After sending a tunneled Router Advertisement as specified in Section
6.2 in response to a received RS, the Edge Router MUST store the
mapping between the LIO and the prefixes contained in the Router
Advertisement. It should then initiate periodic sending of
unsolicited Router Advertisements as described in Section 6.2.3. of
[RFC 4861] . The Router Advertisements MUST be created and tunneled
as described in Section 6.2. The Edge Router MAY stop sending Router
Advertisements if it receives a notification from the AN that the
subscriber circuit has gone down. This notification can be received
out-of-band using a mechanism such as the Access Node Control
Protocol (ANCP). Please consult Section 8 for more details.
Krishnan, et al. Standards Track PAGE 11
RFC 6788 Line-ID Option November 2012
7. Line-Identification Option (LIO)
The Line-Identification Option (LIO) is a destination option that can
be included in IPv6 datagrams that tunnel Router Solicitation and
Router Advertisement messages. The use of the Line-ID option in any
other IPv6 datagrams is not defined by this document. Multiple Line-
ID destination options MUST NOT be present in the same IPv6 datagram.
The LIO has no alignment requirement.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option Type | Option Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LineIDLen | Line ID...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Line-Identification Option Layout
Option Type
8-bit identifier of the type of option. The option identifier
for the Line-Identification Option (0x8C) has been allocated by
the IANA.
Option Length
8-bit unsigned integer. The length of the option (excluding the
Option Type and Option Length fields). The value MUST be greater
than 0.
LineIDLen
8-bit unsigned integer. The length of the Line ID field in
number of octets.
Line ID
Variable-length data inserted by the AN describing the
subscriber-agent circuit identifier corresponding to the logical
access loop port of the AN from which the RS was initiated. The
line identification MUST be unique across all the ANs that share
a link to the Edge Router, e.g., one such line- identification
scheme is described in Section 3.9 of [TR101]. The line
identification should be encoded as specified in Section 7.1.
Krishnan, et al. Standards Track PAGE 12
RFC 6788 Line-ID Option November 2012
7.1. Encoding of the Line ID Field Content
This IPv6 Destination option is derived from an existing widely
deployed DHCPv6 option [RFC 4649], which is in turn derived from a
widely deployed DHCPv4 option [RFC 3046]. These options derive from
and cite the basic DHCP options specification [RFC 2132]. These
widely deployed DHCP options use the Network Virtual Terminal (NVT)
character set [RFC 2132] [RFC 20]. Since the data carried in the
Line-ID option is used in the same manner by the provisioning systems
as the DHCP options, it is beneficial for it to maintain the same
encoding as the DHCP options.
The IPv6 Line ID option contains a description that identifies the
line using only character positions (decimal 32 to decimal 126,
inclusive) of the US-ASCII character set [X3.4] [RFC 20].
Consistent with [RFC 2132], [RFC 3046], and [RFC 4649], the Line ID
field SHOULD NOT contain the US-ASCII NUL character (decimal 0).
However, implementations receiving this option MUST NOT fail merely
because an ASCII NUL character is (erroneously) present in the Line
ID field.
Some existing widely deployed implementations of Edge Routers and ANs
that support the previously mentioned DHCP option only support
US-ASCII and strip the high-order bit from any 8-bit characters
entered by the device operator. The previously mentioned DHCP
options do not support 8-bit character sets either. Therefore, for
compatibility with the installed base and to maximize
interoperability, the high-order bit of each octet in this field MUST
be set to zero by any device inserting this option in an IPv6 packet.
Consistent with [RFC 3046] and [RFC 4649], this option always uses
binary comparison. Therefore, two Line IDs MUST be equal when they
match when compared byte-by-byte. Line-ID A and Line-ID B match
byte-by-byte when (1) A and B have the same number of bytes, and (2)
for all byte indexes P in A: the value of A at index P has the same
binary value as the value of B at index P.
Two Line IDs MUST NOT be equal if they do not match byte-by-byte.
For example, an IPv6 Line-ID option containing "f123" is not equal to
a Line-ID option "F123".
Intermediate systems MUST NOT alter the contents of the Line ID.
Krishnan, et al. Standards Track PAGE 13
RFC 6788 Line-ID Option November 2012
8. Garbage Collection of Unused Prefixes
Following the mechanism described in this document, the broadband
network associates a prefix to a subscriber line based on the LIO.
Even when the subscriber line goes down temporarily, this prefix
stays allocated to that specific subscriber line, i.e., the prefix is
not returned to the unused pool. When a subscriber line no longer
needs a prefix, the prefix can be reclaimed by manual action
dissociating the prefix from the LIO in the backend systems.
9. Interactions with Secure Neighbor Discovery
Since the RS/RA packets that are protected by the "SEcure Neighbor
Discovery (SEND)" [RFC 3971] are not modified in any way by the
mechanism described in this document, there are no issues with SEND
verification.
10. Acknowledgements
The authors would like to thank Margaret Wasserman, Mark Townsley,
David Miles, John Kaippallimalil, Eric Levy-Abegnoli, Thomas Narten,
Olaf Bonness, Thomas Haag, Wojciech Dec, Brian Haberman, Ole Troan,
Hemant Singh, Jari Arkko, Joel Halpern, Bob Hinden, Ran Atkinson,
Glen Turner, Kathleen Moriarty, David Sinicrope, Dan Harkins, Stephen
Farrell, Barry Leiba, Sean Turner, Ralph Droms, and Mohammed
Boucadair for reviewing this document and suggesting changes.
11. Security Considerations
The line identification information inserted by the AN or the Edge
Router is not protected. This means that this option may be
modified, inserted, or deleted without being detected. In order to
ensure validity of the contents of the Line ID field, the network
between the AN and the Edge Router needs to be trusted.
12. IANA Considerations
This document defines a new IPv6 destination option for carrying line
identification. IANA has assigned the following new destination
option type in the "Destination Options and Hop-by-Hop Options"
registry maintained at
<http://www.iana.org/assignments/ipv6-parameters>:
0x8C Line-Identification Option [RFC 6788]
The act bits for this option are 10 and the chg bit is 0.
Krishnan, et al. Standards Track PAGE 14
RFC 6788 Line-ID Option November 2012
Per this document, IANA has also allocated the following well-known
link-local scope multicast address from the "IPv6 Multicast Address
Space Registry" located at
<http://www.iana.org/assignments/ipv6-multicast-addresses/>:
FF02:0:0:0:0:0:0:10 All-BBF-Access-Nodes [RFC 6788]
13. References
13.1. Normative References
[RFC 1661] Simpson, W., Ed., "The Point-to-Point Protocol (PPP)", STD
51, RFC 1661, July 1994.
[RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC 2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, December 1998.
[RFC 3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC 3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
"SEcure Neighbor Discovery (SEND)", RFC 3971, March 2005.
[RFC 4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC 4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007.
[TR101] Broadband Forum, "Migration to Ethernet-based DSL
aggregation", <http://www.broadband-forum.org/
technical/download/TR-101.pdf>.
[TR124] Broadband Forum, "Functional Requirements for Broadband
Residential Gateway Devices",
<http://www.broadband-forum.org/technical/
download/TR-124_Issue-2.pdf>.
[TR156] Broadband Forum, "Using GPON Access in the context of
TR-101", <http://www.broadband-forum.org/
technical/download/TR-156.pdf>.
Krishnan, et al. Standards Track PAGE 15
RFC 6788 Line-ID Option November 2012
[TR177] Broadband Forum, "IPv6 in the context of TR-101",
<www.broadband-forum.org/technical/download/TR-177.pdf>.
[X3.4] American National Standards Institute, "American Standard
Code for Information Interchange (ASCII)", Standard X3.4,
1968.
13.2. Informative References
[RFC 20] Cerf, V., "ASCII format for network interchange", RFC 20,
October 1969.
[RFC 2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997.
[RFC 3046] Patrick, M., "DHCP Relay Agent Information Option", RFC
3046, January 2001.
[RFC 4649] Volz, B., "Dynamic Host Configuration Protocol for IPv6
(DHCPv6) Relay Agent Remote-ID Option", RFC 4649, August
2006.
[RSDA] Dec, W., "IPv6 Router Solicitation Driven Access
Considered Harmful", Work in Progress, June 2011.
Krishnan, et al. Standards Track PAGE 16
RFC 6788 Line-ID Option November 2012
Authors' Addresses
Suresh Krishnan
Ericsson
8400 Blvd Decarie
Town of Mount Royal, Quebec
Canada
EMail: suresh.krishnan@ericsson.com
Alan Kavanagh
Ericsson
8400 Blvd Decarie
Town of Mount Royal, Quebec
Canada
EMail: alan.kavanagh@ericsson.com
Balazs Varga
Ericsson
Konyves Kalman krt. 11. B.
1097 Budapest
Hungary
EMail: balazs.a.varga@ericsson.com
Sven Ooghe
Alcatel-Lucent
Copernicuslaan 50
2018 Antwerp,
Belgium
Phone:
EMail: sven.ooghe@alcatel-lucent.com
Erik Nordmark
Cisco
510 McCarthy Blvd.
Milpitas, CA, 95035
USA
Phone: +1 408 527 6625
EMail: nordmark@cisco.com
Krishnan, et al. Standards Track PAGE 17
RFC TOTAL SIZE: 38410 bytes
PUBLICATION DATE: Monday, November 19th, 2012
LEGAL RIGHTS: The IETF Trust (see BCP 78)
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