Internet DRAFT - draft-zhu-ccamp-flexe-link-advertisement
draft-zhu-ccamp-flexe-link-advertisement
Network Working Group Y. Zhu
Internet-Draft H. Chen
Intended status: Standards Track China Telecom
Expires: January 17, 2019 M. Chen
Z. Du
Huawei
July 16, 2018
ISIS Extensions for Flex Ethernet Link Advertisement
draft-zhu-ccamp-flexe-link-advertisement-01
Abstract
This document specifies the extensions to the IS-IS routing protocol
to carry and flood Flex Ethernet (FlexE) link state information. The
FlexE link state information is necessary for a node or a controller
to compute a path that is required to over FlexE links.
Requirements Language
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 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on January 17, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. FlexE Link . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. FlexE Sub-link . . . . . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
4.1. FlexE Interface Sub-TLV . . . . . . . . . . . . . . . . . 5
4.2. Channelized FlexE Sub-link Flag . . . . . . . . . . . . . 5
5. Security Consideration . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
Flex Ethernet (FlexE) [I-D.izh-ccamp-flexe-fwk] provides a generic
mechanism for supporting a variety of Ethernet MAC rates that may or
may not correspond to any existing Ethernet PHY rate. This includes
MAC rates that are both greater than (through bonding) and less than
(through sub-rate and channelization) the Ethernet PHY rates used to
carry Ethernet traffic.
FlexE supports interface bonding, a bonded interface is consisted of
from 1 to n 100GBASE-R Ethernet interfaces (other rates of interface
will be supported in the future), the bonded interface is called
FlexE interface in this document. FlexE also supports interface
channelization, a FlexE interface can be channelized into multiple
sub-interfaces, the sub-interface is called FlexE sub-interface in
the rest of this document.
The FlexE mechanism operates using a calendar which assigns 66B block
positions on sub-calendars on each PHY of a FlexE interface to each
of the FlexE flows. The calendar has a granularity of 5G, and has a
length of 20 slots for a 100G interface. Currently, only 100GBASE-R
PHY and 5G granularity are supported in FlexE implementation
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agreement version 1.0 [FlexE], other types (e.g., 200G, 400G) of PHY
and granularities (e.g., 25G) will be supported in the future.
A FlexE interface has a number of time slots resource. These time
slots can be transparent to the upper layer application, the upper
layer application (e.g., RSVP-TE) can just treat the FlexE interface
as a normal Ethernet interface or the time slots can be allocated to
form a FlexE sub-interface though configuration or some dynamic
protocols. The later is called channelization. How to signal or
configure the FlexE sub-interface is out of the scope of this
document.
The logical link that connects two FlexE interfaces residing in two
adjacent nodes is called FlexE link, and the logical link that
connects two FlexE sub-interfaces residing in two adjacent nodes is
call FlexE sub-link.
More details about FlexE can be found in FlexE framework document
[I-D.izh-ccamp-flexe-fwk].
This document defines extensions to ISIS protocol to advertise the
FlexE link and sub-link state information.
2. FlexE Link
A FlexE link is a logical link that connects two FlexE interfaces, it
looks like a LAG (Link Aggregation Group).
This document defines a new sub-TLV, which is referred to as FlexE
Interface sub-TLV, to the extended IS reachability TLV [RFC5303]. It
is defined to describes the resources and attributes of a FlexE
interface. The format of FlexE Interface sub-TLV is as below:
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 = TBD1 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FlexE Group Number | Granularity | Reserved|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available Slots |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: FlexE Interface sub-TLV
The Type field is 1 octet in length and the value is TBD1.
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The Length field is 1 octet in length that indicates the length (8)
of the value field of the sub-TLV in octet.
FlexE Group Number field is 20 bits in length and carries the FlexE
Group [FlexE] number of the FlexE Group that the FlexE interface
belongs.
The Granularity is 1 octet in length and its value identifies the
granularity of the FlexE time slots of a FlexE interface. Current
OIF agreement only allows the "5G" granularity, other granularities
may be defined in the future.
Value Granularity
----- --------------
0 Reserved
1 5G
2-254 Unassigned
255 Reserved
For each PHY of a FlexE interface, there are two calendars, one is
called Active calendar and the other is called Backup calendar. The
two calendars are used to facilitate reconfiguration, for example,
FlexE flow resizing can be achieved through calendar updates. More
detail about FlexE calendar can be found [FlexE].
The Available Slots fields is 4-octet in length that indicates the
maximum number of slots available on the active calendar of the FlexE
interface.
For a FlexE interface, 5G granularity is only supported in [FlexE],
more granularities may be supported in the future. To support this,
FlexE Interface sub-TLV can occur multiple times in an extended IS
reachability TLV, but for each granularity, only one FlexE Interface
sub-TLV can be included and it carries the available time slots of
the granularity of the FlexE interface. When multiple FlexE
Interface sub-TLVs for the same granularity occur, only the first
FlexE Interface sub-TLV is considered to be valid, the rests MUST be
ignored.
3. FlexE Sub-link
Through channelization, a FlexE interface can be sliced into a number
of FlexE sub-interfaces, each FlexE sub-interface has dedicated
bandwidth and is isolated from other FlexE sub-interfaces. A set of
FlexE sub-interfaces can be allocated to a specific application/user
to form a sliced network. Or a series of FlexE sub-interfaces can be
concatenated (e.g., through Segment Routing) to form a leased line.
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A FlexE sub-link connects two FlexE sub-interfaces. From link
characteristic point of view, a FlexE sub-link is same as an Ethernet
link, it can be advertised and used as a normal link. But for some
scenarios, it may be useful to indicate whether a link is a
channelized FlexE sub-link. Then a controller or a node can use this
information to determine whether a path should be over the link.
Therefore, this document defines a new flag, which is referred to as
Channelized FlexE sub-link, to the Link Attributes sub-TLV[RFC5029].
4. IANA Considerations
4.1. FlexE Interface Sub-TLV
IANA is requested to allocate the following new sub-TLV types of top-
level TLV 22 that have been reflected in the IS-IS sub-TLV registry
for TLV 22:
Value sub-TLV Name Reference
----- --------------- -------------
TBD1 FlexE Interface This document
4.2. Channelized FlexE Sub-link Flag
IANA is requested to allocate the following new bit value to "link-
attribute bit values for sub-TLV 19 of TLV 22".
Value Name Reference
----- ---- ---------
TBD2 Channelized FlexE sub-link This document
5. Security Consideration
This document describes a mechanism for advertising FlexE link state
information through IS-IS LSPs and does not introduce any new
security issues.
6. Acknowledgements
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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[RFC5029] Vasseur, JP. and S. Previdi, "Definition of an IS-IS Link
Attribute Sub-TLV", RFC 5029, DOI 10.17487/RFC5029,
September 2007, <https://www.rfc-editor.org/info/rfc5029>.
[RFC5303] Katz, D., Saluja, R., and D. Eastlake 3rd, "Three-Way
Handshake for IS-IS Point-to-Point Adjacencies", RFC 5303,
DOI 10.17487/RFC5303, October 2008,
<https://www.rfc-editor.org/info/rfc5303>.
7.2. Informative References
[FlexE] OIF, "Flex Ethernet Implementation Agreement Version 1.0
(OIF-FLEXE-01.0)", March 2016.
[I-D.izh-ccamp-flexe-fwk]
Hussain, I., Valiveti, R., Wang, Q., Andersson, L., Chen,
M., and z. zhenghaomian@huawei.com, "GMPLS Routing and
Signaling Framework for Flexible Ethernet (FlexE)", draft-
izh-ccamp-flexe-fwk-05 (work in progress), March 2018.
Authors' Addresses
Yongqing Zhu
China Telecom
109, West Zhongshan Road, Tianhe District, Guangzhou,China
Email: zhuyq@gsta.com
Huanan Chen
China Telecom
109, West Zhongshan Road, Tianhe District, Guangzhou,China
Email: chenhuanan@gsta.com
Mach(Guoyi) Chen
Huawei
Email: mach.chen@huawei.com
Zongpeng Du
Huawei
Email: duzongpeng@huawei.com
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