draft-ietf-6man-dad-proxy-03.txt   draft-ietf-6man-dad-proxy-04.txt 
6man Working Group F. Costa 6man Working Group F. Costa
Internet-Draft J-M. Combes Internet-Draft J-M. Combes
Intended status: Standards Track X. Pougnard Intended status: Standards Track X. Pougnard
Expires: December 14, 2012 France Telecom Orange Expires: December 17, 2012 France Telecom Orange
H. Li H. Li
Huawei Technologies Huawei Technologies
June 12, 2012 June 15, 2012
Duplicate Address Detection Proxy Duplicate Address Detection Proxy
draft-ietf-6man-dad-proxy-03 draft-ietf-6man-dad-proxy-04
Abstract Abstract
The document describes a mechanism allowing the use of Duplicate The document describes a mechanism allowing the use of Duplicate
Address Detection (DAD) by IPv6 nodes in a point-to-multipoint Address Detection (DAD) by IPv6 nodes in a point-to-multipoint
architecture with "split-horizon" forwarding scheme. Based on the architecture with "split-horizon" forwarding scheme. Based on the
DAD signalling, the first hop router stores in a Binding Table all DAD signalling, the first hop router stores in a Binding Table all
known IPv6 addresses used on a point-to-multipoint domain (e.g. known IPv6 addresses used on a point-to-multipoint domain (e.g.
VLAN). When a node performs DAD for an address already used by VLAN). When a node performs DAD for an address already used by
another node, the first hop router replies instead of this last one. another node, the first hop router replies instead of this last one.
skipping to change at page 1, line 39 skipping to change at page 1, line 39
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 14, 2012. This Internet-Draft will expire on December 17, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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Layer Address Field in the entry, that means the CPE is still Layer Address Field in the entry, that means the CPE is still
performing DAD for this address. The BNG MUST NOT reply to the CPE performing DAD for this address. The BNG MUST NOT reply to the CPE
or forward the NS message. or forward the NS message.
When these conditions are met and the source address of the Link- When these conditions are met and the source address of the Link-
Layer Header in the NS message is not equal to the address in the Layer Header in the NS message is not equal to the address in the
Link-Layer Address Field in the entry, that means possibly another Link-Layer Address Field in the entry, that means possibly another
CPE performs DAD for an already owned address. The BNG then has to CPE performs DAD for an already owned address. The BNG then has to
verify whether there is a real conflict by checking if the CPE whose verify whether there is a real conflict by checking if the CPE whose
IPv6 address is in the entry is still connected. In the following, IPv6 address is in the entry is still connected. In the following,
we will call IPv6-CPE1 the IPv6 address of the existing entry, Link- we will call IPv6-CPE1 the IPv6 address of the existing entry in the
layer-CPE1 the Link-layer address of that entry and Link-layer-CPE2 Binding Table, Link-layer-CPE1 the Link-layer address of that entry
the Link-layer address of the CPE which is performing DAD, which is and Link-layer-CPE2 the Link-layer address of the CPE which is
different from Link-layer-CPE1. performing DAD, which is different from Link-layer-CPE1.
The BNG MUST check if the potential address conflict is real. In The BNG MUST check if the potential address conflict is real. In
particular: particular:
o If IPv6-CPE1 is in the Neighbor Cache and it is associated with o If IPv6-CPE1 is in the Neighbor Cache and it is associated with
Link-layer-CPE1, the reachability of IPv6-CPE1 MUST be confirmed Link-layer-CPE1, the reachability of IPv6-CPE1 MUST be confirmed
as explained in Section 4.2.3. as explained in Section 4.2.3.
o If IPv6-CPE1 is in the Neighbor Cache, but it is associated with o If IPv6-CPE1 is in the Neighbor Cache, but in this cache it is
another Link-layer address than Link-layer-CPE1, that means that associated with another Link-layer address than Link-layer-CPE1,
there is possibly a conflict with another CPE, but that CPE did that means that there is possibly a conflict with another CPE, but
not perform DAD. This situation is out of the scope of this that CPE did not perform DAD. This situation is out of the scope
document, since one assumption made above is that all the nodes of of this document, since one assumption made above is that all the
a point-to-multipoint domain (except the DAD proxy itself) perform nodes of a point-to-multipoint domain (except the DAD proxy
DAD. This case could be covered in the future by additional itself) perform DAD. This case could be covered in the future by
solutions that work in conjunction with the DAD proxy. additional solutions that work in conjunction with the DAD proxy.
o If IPv6-CPE1 is not in the Neighbor Cache, then the BNG MUST o If IPv6-CPE1 is not in the Neighbor Cache, then the BNG MUST
create a new entry based on the information of the entry in the create a new entry based on the information of the entry in the
Binding Table. This step is necessary in order to trigger the Binding Table. This step is necessary in order to trigger the
reachibility check as explained in Section 4.2.3. The entry in reachibility check as explained in Section 4.2.3. The entry in
the Neighbor Cache MUST be created based on the algorithm defined the Neighbor Cache MUST be created based on the algorithm defined
in section 7.3.3 of [RFC4861], in particular by considering the in section 7.3.3 of [RFC4861], in particular by considering the
case as if a packet other than a solicited Neighbor Advertisement case as if a packet other than a solicited Neighbor Advertisement
was received from IPv6-CPE1. That means that the new entry of the was received from IPv6-CPE1. That means that the new entry of the
Neighbor Cache MUST contain the following information: Neighbor Cache MUST contain the following information:
 End of changes. 6 change blocks. 
16 lines changed or deleted 16 lines changed or added

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