draft-ietf-mpls-tp-ethernet-addressing-05.txt   draft-ietf-mpls-tp-ethernet-addressing-06.txt 
MPLS D. Frost MPLS D. Frost
Internet-Draft S. Bryant Internet-Draft S. Bryant
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: August 5, 2013 M. Bocci Expires: October 10, 2013 M. Bocci
Alcatel-Lucent Alcatel-Lucent
February 1, 2013 April 08, 2013
MPLS-TP Next-Hop Ethernet Addressing MPLS-TP Next-Hop Ethernet Addressing
draft-ietf-mpls-tp-ethernet-addressing-05 draft-ietf-mpls-tp-ethernet-addressing-06
Abstract Abstract
The Multiprotocol Label Switching (MPLS) Transport Profile (MPLS-TP) The Multiprotocol Label Switching (MPLS) Transport Profile (MPLS-TP)
is the set of MPLS protocol functions applicable to the construction is the set of MPLS protocol functions applicable to the construction
and operation of packet-switched transport networks. This document and operation of packet-switched transport networks. This document
presents considerations for link-layer addressing of Ethernet frames presents considerations for link-layer addressing of Ethernet frames
carrying MPLS-TP packets. carrying MPLS-TP packets.
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 5, 2013. This Internet-Draft will expire on October 10, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 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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functions that meet the requirements [RFC5654] for the application of functions that meet the requirements [RFC5654] for the application of
MPLS to the construction and operation of packet-switched transport MPLS to the construction and operation of packet-switched transport
networks. The MPLS-TP data plane consists of those MPLS-TP functions networks. The MPLS-TP data plane consists of those MPLS-TP functions
concerned with the encapsulation and forwarding of MPLS-TP packets concerned with the encapsulation and forwarding of MPLS-TP packets
and is described in [RFC5960]. and is described in [RFC5960].
This document presents considerations for link-layer addressing of This document presents considerations for link-layer addressing of
Ethernet frames carrying MPLS-TP packets. Since MPLS-TP packets are Ethernet frames carrying MPLS-TP packets. Since MPLS-TP packets are
MPLS packets, existing procedures ([RFC3032], [RFC5332]) for the MPLS packets, existing procedures ([RFC3032], [RFC5332]) for the
encapsulation of MPLS packets over Ethernet apply. Because IP encapsulation of MPLS packets over Ethernet apply. Because IP
functionality is optional in an MPLS-TP network, however, IP-based functionality is only optional in an MPLS-TP network, IP-based
protocols for Media Access Control (MAC) address learning, such as protocols for Media Access Control (MAC) address learning, such as
the Address Resolution Protocol (ARP) [RFC0826] and IP version 6 the Address Resolution Protocol (ARP) [RFC0826] and IP version 6
Neighbor Discovery [RFC4861], may not be available. This document Neighbor Discovery [RFC4861], may not be available. This document
specifies the options for determination and selection of next-hop specifies the options for the determination and selection of the
Ethernet MAC addressing under these circumstances. next-hop Ethernet MAC address when MPLS-TP is used between nodes that
do not have an IP dataplane.
1.1. Terminology 1.1. Terminology
Term Definition Term Definition
------- --------------------------- ------- ---------------------------
ARP Address Resolution Protocol ARP Address Resolution Protocol
G-ACh Generic Associated Channel G-ACh Generic Associated Channel
LSP Label Switched Path LSP Label Switched Path
LSR Label Switching Router LSR Label Switching Router
MAC Media Access Control MAC Media Access Control
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In view of the above considerations, the approach which SHOULD be In view of the above considerations, the approach which SHOULD be
used, is therefore to configure both nodes to use the method used, is therefore to configure both nodes to use the method
described in this document which uses, as a destination MAC address, described in this document which uses, as a destination MAC address,
an Ethernet multicast address reserved for MPLS-TP for use over an Ethernet multicast address reserved for MPLS-TP for use over
point-to-point links. The address allocated for this purpose by the point-to-point links. The address allocated for this purpose by the
Internet Assigned Numbers Authority (IANA) is 01-00-5E-90-00-00. An Internet Assigned Numbers Authority (IANA) is 01-00-5E-90-00-00. An
MPLS-TP implementation MUST process Ethernet frames received over a MPLS-TP implementation MUST process Ethernet frames received over a
point-to-point link with this destination MAC address by default. point-to-point link with this destination MAC address by default.
The use of broadcast or multicast addressing for the purpose The use of broadcast or multicast addressing for the purpose
described in this section, i.e. as a placeholder for the unknown described in this section, i.e. as a placeholder for the unknown
unicast MAC address of the destination, is applicable only when the unicast MAC address of the destination, is applicable only when the
attached Ethernet link is known to be point-to-point. If a link is attached Ethernet link is known to be point-to-point. If a link is
not known to be point-to-point, these forms of addressing MUST NOT be not known to be point-to-point, these forms of broadcast or multicast
used. Thus the implementation MUST provide a means for the operator addressing MUST NOT be used. Thus the implementation MUST provide a
to declare that a link is point-to-point if it supports these means for the operator to declare that a link is point-to-point if it
addressing modes. Moreover, the operator is cautioned that it is not supports these addressing modes. Moreover, the operator is cautioned
always clear whether a given link is, or will remain, strictly point- that it is not always clear whether a given link is, or will remain,
to-point, particularly when the link is supplied by an external strictly point-to-point, particularly when the link is supplied by an
provider; point-to-point declarations must therefore be used with external provider; point-to-point declarations must therefore be used
care. Because of these caveats it is RECOMMENDED that with care. Because of these caveats it is RECOMMENDED that
implementations support the procedures in Section 4 so that unicast implementations support the procedures in Section 4 so that unicast
addressing can be used. addressing can be used.
3. Multipoint Link Addressing 3. Multipoint Link Addressing
When a multipoint Ethernet link serves as a section [RFC5960] for a When a multipoint Ethernet link serves as a section [RFC5960] for a
point-to-multipoint MPLS-TP LSP, and multicast destination MAC point-to-multipoint MPLS-TP LSP, and multicast destination MAC
addressing at the Ethernet layer is used for the LSP, the addressing addressing at the Ethernet layer is used for the LSP, the addressing
and encapsulation procedures specified in [RFC5332] SHALL be used. and encapsulation procedures specified in [RFC5332] SHALL be used.
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Ethernet frames carrying packets of the LSP. According to the Ethernet frames carrying packets of the LSP. According to the
discussion in the previous section, this implies the use of either discussion in the previous section, this implies the use of either
static MAC address configuration or a protocol that enables peer MAC static MAC address configuration or a protocol that enables peer MAC
address discovery. address discovery.
4. MAC Address Discovery via the G-ACh Advertisement Protocol 4. MAC Address Discovery via the G-ACh Advertisement Protocol
The G-ACh Advertisement Protocol (GAP) [I-D.ietf-mpls-gach-adv] The G-ACh Advertisement Protocol (GAP) [I-D.ietf-mpls-gach-adv]
provides a simple means of informing listeners on a link of the provides a simple means of informing listeners on a link of the
sender's capabilities and configuration. When used for this purpose sender's capabilities and configuration. When used for this purpose
on an Ethernet link, GAP messages are multicast to the address 01-00- on an Ethernet link, GAP messages are multicast to the address
5e-80-00-0d. If these messages contain the unicast MAC address of 01-00-5e-80-00-0d (see [I-D.ietf-mpls-gach-adv] Section 7). If these
the sender, then listeners can learn this address and use it in the messages contain the unicast MAC address of the sender, then
future when transmitting frames containing MPLS-TP packets. Since listeners can learn this address and use it in the future when
the GAP does not rely on IP, this provides a means of unicast MAC transmitting frames containing MPLS-TP packets. Since the GAP does
discovery for MPLS-TP nodes without IP support. not rely on IP, this provides a means of unicast MAC discovery for
MPLS-TP nodes without IP support.
This document defines a new GAP application "Ethernet Interface This document defines a new GAP application "Ethernet Interface
Parameters" (TBD1), to support the advertisement of Ethernet-specific Parameters" (TBD1), to support the advertisement of Ethernet-specific
parameters associated with the sending interface. The following parameters associated with the sending interface. The following
Type-Length-Value (TLV) objects are defined for this application; the Type-Length-Value (TLV) objects are defined for this application; the
TLV format is as defined in [I-D.ietf-mpls-gach-adv]: TLV format is as defined in [I-D.ietf-mpls-gach-adv]:
Source MAC Address (type = 0, length = 8): The Value of this Source MAC Address (type = 0, length = 8): The Value of this
object is an EUI-64 [EUI-64] unicast MAC address assigned to one object is an EUI-64 [EUI-64] unicast MAC address assigned to one
of the interfaces of the sender that is connected to this data of the interfaces of the sender that is connected to this data
link. The IEEE-defined mapping from 48-bit MAC addresses to link. The IEEE-defined mapping from 48-bit MAC addresses to
EUI-64 form is used. EUI-64 form is used.
MTU (type = 1, length = 4): The Value of this object is a 32-bit MTU (type = 1, length = 4): The Value of this object is a 32-bit
unsigned integer encoded in network byte order that specifies the unsigned integer encoded in network byte order that specifies the
maximum transmission unit size of the sending interface, in maximum transmission unit size in octets of an MPLS label stack
octets. plus payload that can be sent over the sending interface. Where
MAC address learning occurs by some other means, this TLV group
MAY be used to advertise only the MTU. If multiple advertisements
are made for the same parameter, use of these advertisements is
undefined.
Where MAC address learning occurs by some other means, this TLV group 0 1 2 3
MAY be used to advertise only the MTU. If multiple adverisements are 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
made for the the same parameter, use of these advertisments is +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
undefined. | Type=0 | Reserved | Length=8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address in EUI-64 Format |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
In the event of the persistent loss of the GAP messages, the Figure 1: Source MAC Address Object Format
receiving node MUST assume that it is now connected to a node that
does not support these advertisements and must behave as configured 0 1 2 3
for this eventuality. 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=1 | Reserved | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: TLV Object Format
Per [I-D.ietf-mpls-gach-adv], MAC Address Discovery information needs
to be periodically retransmitted and is to be retained by a receiver
based on the period of time indicated by the associated Lifetime
field. To expedite the initialization of a link it is RECOMMENDED
that a node that has been reconfigured, rebooted or is aware that it
have been disconnected from its peer send a GAP Ethernet Interface
Parameter message, and that it issues a GAP request message for the
Ethernet parameters at the earliest opportunity.
When the MAC address in the received Source MAC Address TLV changes
the new MAC address MUST be used (see Section 5.2 of
[I-D.ietf-mpls-gach-adv]).
If a minimum MTU is configured for a link and the MTU advertised by
the peer is lower than that minimum, the operator MUST be notified of
the MTU mismatch. Under these circumstances the operator may choose
to configure the LSR to shut the link, thereby triggering a fault,
and hence causing the end-to-end path to be repaired. Alternatively
the operator may choose to configure the LSR to leave the link up so
that an OAM message can be used to verify the actual MTU.
In the event a GAP message is not received within the previously
received associated Lifetime, the receiving node MUST assume that it
is now connected to a node that does not support these advertisements
and must behave as configured for this eventuality.
5. Manageability Considerations 5. Manageability Considerations
The values sent and received by this protocol MUST be made accessible The values sent and received by this protocol MUST be made accessible
for inspection by network operators, and where local configuration is for inspection by network operators, and where local configuration is
updated by the received information, it MUST be clear why the updated by the received information, it MUST be clear why the
configured value has been changed. The advertised information SHOULD configured value has been changed. The advertised information SHOULD
be persistent across restarts. Received advertisements MUST be be persistent across restarts. Received advertisements MUST be
discarded across restarts. If the received values change, the new discarded across restarts. If the received values change, the new
values MUST be used and the change made visible to the network values MUST be used and the change made visible to the network
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are aware of the Ethernet link type (point-to-point or multipoint). are aware of the Ethernet link type (point-to-point or multipoint).
In the case of multipoint links, the operator SHOULD either ensure In the case of multipoint links, the operator SHOULD either ensure
that no devices are attached to the link that are not authorized to that no devices are attached to the link that are not authorized to
receive the frames, or take steps to mitigate the possibility of receive the frames, or take steps to mitigate the possibility of
excessive frame distribution, for example by configuring the Ethernet excessive frame distribution, for example by configuring the Ethernet
switch to appropriately restrict the delivery of multicast frames to switch to appropriately restrict the delivery of multicast frames to
authorized ports. authorized ports.
An attacker could disrupt communications by modifying the Source MAC An attacker could disrupt communications by modifying the Source MAC
Address or the MTU values, however this is mitigated by the use of Address or the MTU values, however this is mitigated by the use of
cryptographic authetication as described in [I-D.ietf-mpls-gach-adv] cryptographic authentication as described in [I-D.ietf-mpls-gach-adv]
which also describes other considerations applicable to the GAP which also describes other considerations applicable to the GAP
protocol. Visibility into the contents of either of the TLVs could protocol. Visibility into the contents of either of the TLVs could
provide information that is useful for an attacker. This is best provide information that is useful for an attacker. This is best
addressed by physical security of the links. addressed by physical security of the links.
7. IANA Considerations 7. IANA Considerations
7.1. Ethernet Multicast Address Allocation 7.1. Ethernet Multicast Address Allocation
IANA has allocated an Ethernet multicast address from the "IANA IANA has allocated an Ethernet multicast address from the "IANA
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01-00-5E-90-00-00. IANA is requested to update the reference to 01-00-5E-90-00-00. IANA is requested to update the reference to
point to the RFC number assigned to this document. point to the RFC number assigned to this document.
7.2. G-ACh Advertisement Protocol Allocation 7.2. G-ACh Advertisement Protocol Allocation
IANA is requested to allocate a new Application ID in the "G-ACh IANA is requested to allocate a new Application ID in the "G-ACh
Advertisement Protocol Applications" registry Advertisement Protocol Applications" registry
[I-D.ietf-mpls-gach-adv] (currently located in the "Pseudowire Name [I-D.ietf-mpls-gach-adv] (currently located in the "Pseudowire Name
Spaces (PWE3)"), as follows: Spaces (PWE3)"), as follows:
Application ID Description Reference Application ID Description Reference
--------------------------- ---------------------------- ------------ ------------------------- --------------------------- ---------------
TBD1 to be assigned by IANA Ethernet Interface (this draft) TBD1 to be assigned by Ethernet Interface (this draft)
Parameters IANA Parameters
7.3. Creation of Ethernet Interface Parameters Registry 7.3. Creation of Ethernet Interface Parameters Registry
IANA is requested to create a new registry, "G-ACh Advertisement IANA is requested to create a new registry, "G-ACh Advertisement
Protocol: Ethernet Interface Parameters" within the "Pseudowire Name Protocol: Ethernet Interface Parameters" within the "Pseudowire Name
Spaces (PWE3)" with fields and initial allocations as follows: Spaces (PWE3)" with fields and initial allocations as follows:
Type Name Type ID Reference Type Name Type ID Reference
------------------ ------- ------------ ------------------ ------- ------------
Source MAC Address 0 (this draft) Source MAC Address 0 (this draft)
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8. Acknowledgements 8. Acknowledgements
We thank Adrian Farrel for his valuable review comments on this We thank Adrian Farrel for his valuable review comments on this
document. document.
9. References 9. References
9.1. Normative References 9.1. Normative References
[EUI-64] "[EUI64] IEEE, "Guidelines for 64-bit Global Identifier [EUI-64] , "[EUI64] IEEE, "Guidelines for 64-bit Global Identifier
(EUI-64) Registration Authority", http:// (EUI-64) Registration Authority", http://
standards.ieee.org/regauth/oui/tutorials/EUI64.html, March standards.ieee.org/regauth/oui/tutorials/EUI64.html, March
1997.". 1997.", .
[I-D.ietf-mpls-gach-adv] [I-D.ietf-mpls-gach-adv]
Frost, D., Bryant, S., and M. Bocci, "MPLS Generic Frost, D., Bryant, S., and M. Bocci, "MPLS Generic
Associated Channel (G-ACh) Advertisement Protocol", Associated Channel (G-ACh) Advertisement Protocol", draft-
draft-ietf-mpls-gach-adv-04 (work in progress), ietf-mpls-gach-adv-06 (work in progress), February 2013.
December 2012.
[LLDP] "IEEE, "Station and Media Access Control Connectivity [LLDP] , "IEEE, "Station and Media Access Control Connectivity
Discovery (802.1AB)", September 2009.". Discovery (802.1AB)", September 2009.", .
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., [RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, January 2001. Encoding", RFC 3032, January 2001.
[RFC5332] Eckert, T., Rosen, E., Aggarwal, R., and Y. Rekhter, "MPLS [RFC5332] Eckert, T., Rosen, E., Aggarwal, R., and Y. Rekhter, "MPLS
Multicast Encapsulations", RFC 5332, August 2008. Multicast Encapsulations", RFC 5332, August 2008.
skipping to change at page 8, line 6 skipping to change at page 9, line 10
[RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or [RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or
converting network protocol addresses to 48.bit Ethernet converting network protocol addresses to 48.bit Ethernet
address for transmission on Ethernet hardware", STD 37, address for transmission on Ethernet hardware", STD 37,
RFC 826, November 1982. RFC 826, November 1982.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007. September 2007.
[RFC5921] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. [RFC5921] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L.
Berger, "A Framework for MPLS in Transport Networks", Berger, "A Framework for MPLS in Transport Networks", RFC
RFC 5921, July 2010. 5921, July 2010.
Authors' Addresses Authors' Addresses
Dan Frost Dan Frost
Cisco Systems Cisco Systems
Email: danfrost@cisco.com Email: danfrost@cisco.com
Stewart Bryant Stewart Bryant
Cisco Systems Cisco Systems
 End of changes. 20 change blocks. 
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