draft-ietf-opsawg-large-flow-load-balancing-04.txt		draft-ietf-opsawg-large-flow-load-balancing-05.txt
	OPSAWG R. Krishnan		OPSAWG R. Krishnan
	Internet Draft S. Khanna		Internet Draft Brocade Communications
	Intended status: Informational Brocade Communications		Intended status: Informational L. Yong
	Expires: January 9, 2014 L. Yong		Expires: February 23, 2014 Huawei USA
	July 9, 2013 Huawei USA		August 23, 2013 A. Ghanwani
	A. Ghanwani
	Dell		Dell
	Ning So		Ning So
	Tata Communications		Tata Communications
			S. Khanna
			Cisco Systems
	B. Khasnabish		B. Khasnabish
	ZTE Corporation		ZTE Corporation
	Mechanisms for Optimal LAG/ECMP Component Link Utilization in		Mechanisms for Optimal LAG/ECMP Component Link Utilization in
	Networks		Networks
	draft-ietf-opsawg-large-flow-load-balancing-04.txt		draft-ietf-opsawg-large-flow-load-balancing-05.txt
	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. This document may not be modified,		provisions of BCP 78 and BCP 79. This document may not be modified,
	and derivative works of it may not be created, except to publish it		and derivative works of it may not be created, except to publish it
	as an RFC and to translate it into languages other than English.		as an RFC and to translate it into languages other than English.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	skipping to change at page 1, line 42		skipping to change at page 1, line 43
	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."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt		http://www.ietf.org/ietf/1id-abstracts.txt
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html		http://www.ietf.org/shadow.html
	This Internet-Draft will expire on January 9, 2014.		This Internet-Draft will expire on February 23, 2014.
	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
	skipping to change at page 2, line 27		skipping to change at page 2, line 27
	Demands on networking infrastructure are growing exponentially; the		Demands on networking infrastructure are growing exponentially; the
	drivers are bandwidth hungry rich media applications, inter-data		drivers are bandwidth hungry rich media applications, inter-data
	center communications, etc. In this context, it is important to		center communications, etc. In this context, it is important to
	optimally use the bandwidth in wired networks that extensively use		optimally use the bandwidth in wired networks that extensively use
	LAG/ECMP techniques for bandwidth scaling. This draft explores some		LAG/ECMP techniques for bandwidth scaling. This draft explores some
	of the mechanisms useful for achieving this.		of the mechanisms useful for achieving this.
	Table of Contents		Table of Contents
	1. Introduction...................................................3		1. Introduction...................................................3
	1.1. Acronyms..................................................3		1.1. Acronyms..................................................4
	1.2. Terminology...............................................4		1.2. Terminology...............................................4
	2. Flow Categorization............................................4		2. Flow Categorization............................................4
	3. Hash-based Load Distribution in LAG/ECMP.......................5		3. Hash-based Load Distribution in LAG/ECMP.......................5
	4. Mechanisms for Optimal LAG/ECMP Component Link Utilization.....7		4. Mechanisms for Optimal LAG/ECMP Component Link Utilization.....7
	4.1. Differences in LAG vs ECMP................................8		4.1. Differences in LAG vs ECMP................................8
	4.2. Overview of the mechanism.................................9		4.2. Overview of the mechanism.................................9
	4.3. Large Flow Recognition...................................10		4.3. Large Flow Recognition...................................10
	4.3.1. Flow Identification.................................10		4.3.1. Flow Identification.................................10
	4.3.2. Criteria for Identifying a Large Flow...............10		4.3.2. Criteria for Identifying a Large Flow...............10
	4.3.3. Sampling Techniques.................................11		4.3.3. Sampling Techniques.................................11
	skipping to change at page 3, line 10		skipping to change at page 3, line 10
	5. Information Model for Flow Re-balancing.......................15		5. Information Model for Flow Re-balancing.......................15
	5.1. Configuration Parameters for Flow Re-balancing...........16		5.1. Configuration Parameters for Flow Re-balancing...........16
	5.2. System Configuration and Identification Parameters.......16		5.2. System Configuration and Identification Parameters.......16
	5.3. Information for Alternative Placement of Large Flows.....17		5.3. Information for Alternative Placement of Large Flows.....17
	5.4. Information for Redistribution of Small Flows............17		5.4. Information for Redistribution of Small Flows............17
	5.5. Export of Flow Information...............................17		5.5. Export of Flow Information...............................17
	5.6. Monitoring information...................................18		5.6. Monitoring information...................................18
	5.6.1. Interface (link) utilization........................18		5.6.1. Interface (link) utilization........................18
	5.6.2. Other monitoring information........................18		5.6.2. Other monitoring information........................18
	6. Operational Considerations....................................18		6. Operational Considerations....................................18
			6.1. Rebalancing Frequency....................................19
			6.2. Handling Route Changes...................................19
	7. IANA Considerations...........................................19		7. IANA Considerations...........................................19
	8. Security Considerations.......................................19		8. Security Considerations.......................................19
	9. Acknowledgements..............................................20		9. Acknowledgements..............................................20
	10. References...................................................20		10. References...................................................20
	10.1. Normative References....................................20		10.1. Normative References....................................20
	10.2. Informative References..................................20		10.2. Informative References..................................20
	1. Introduction		1. Introduction
	Networks extensively use LAG/ECMP techniques for capacity scaling.		Networks extensively use LAG/ECMP techniques for capacity scaling.
	skipping to change at page 19, line 4		skipping to change at page 19, line 6
	5.6.2. Other monitoring information		5.6.2. Other monitoring information
	Additional monitoring information includes:		Additional monitoring information includes:
	. Number of times rebalancing was done.		. Number of times rebalancing was done.
	. Time since the last rebalancing event.		. Time since the last rebalancing event.
	6. Operational Considerations		6. Operational Considerations
			6.1. Rebalancing Frequency
	Flows should be re-balanced only when the imbalance in the		Flows should be re-balanced only when the imbalance in the
	utilization across component links exceeds a certain threshold.		utilization across component links exceeds a certain threshold.
	Frequent re-balancing to achieve precise equitable utilization across		Frequent re-balancing to achieve precise equitable utilization across
	component links could be counter-productive as it may result in		component links could be counter-productive as it may result in
	moving flows back and forth between the component links impacting		moving flows back and forth between the component links impacting
	packet ordering and system stability. This applies regardless of		packet ordering and system stability. This applies regardless of
	whether large flows or small flows are re-distributed. It should be		whether large flows or small flows are re-distributed. It should be
	noted that reordering is a concern for TCP flows with even a few		noted that reordering is a concern for TCP flows with even a few
	packets because three out-of-order packets would trigger sufficient		packets because three out-of-order packets would trigger sufficient
	duplicate ACKs to the sender resulting in a retransmission [RFC		duplicate ACKs to the sender resulting in a retransmission [RFC
	5681].		5681].
	The operator would have to experiment with various values of the		The operator would have to experiment with various values of the
	large flow recognition parameters (minimum bandwidth threshold,		large flow recognition parameters (minimum bandwidth threshold,
	observation interval) and the imbalance threshold across component		observation interval) and the imbalance threshold across component
	links to tune the solution for their environment.		links to tune the solution for their environment.
			6.2. Handling Route Changes
			Large flow rebalancing must be aware of any changes to the FIB. In
			cases where the next-hop of a route no longer to points to the LAG,
			or to an ECMP group, any PBR entries added as described in Section
			4.4.1 and 4.4.2 must be withdrawn in order to avoid the creation of
			forwarding loops.
	7. IANA Considerations		7. IANA Considerations
	This memo includes no request to IANA.		This memo includes no request to IANA.
	8. Security Considerations		8. Security Considerations
	This document does not directly impact the security of the Internet		This document does not directly impact the security of the Internet
	infrastructure or its applications. In fact, it could help if there		infrastructure or its applications. In fact, it could help if there
	is a DOS attack pattern which causes a hash imbalance resulting in		is a DOS attack pattern which causes a hash imbalance resulting in
	heavy overloading of large flows to certain LAG/ECMP component		heavy overloading of large flows to certain LAG/ECMP component
	skipping to change at page 21, line 33		skipping to change at page 21, line 38
	the ACM SIGCOMM, August 2011.		the ACM SIGCOMM, August 2011.
	[NDTM] Estan, C. and G. Varghese, "New directions in traffic		[NDTM] Estan, C. and G. Varghese, "New directions in traffic
	measurement and accounting," Proceedings of ACM SIGCOMM, August 2002.		measurement and accounting," Proceedings of ACM SIGCOMM, August 2002.
	[bin-pack] Coffman, Jr., E., M. Garey, and D. Johnson. Approximation		[bin-pack] Coffman, Jr., E., M. Garey, and D. Johnson. Approximation
	Algorithms for Bin-Packing -- An Updated Survey. In Algorithm Design		Algorithms for Bin-Packing -- An Updated Survey. In Algorithm Design
	for Computer System Design, ed. by Ausiello, Lucertini, and Serafini.		for Computer System Design, ed. by Ausiello, Lucertini, and Serafini.
	Springer-Verlag, 1984.		Springer-Verlag, 1984.
	Appendix A. Internet Traffic Analysis and Load Balancing Simulation		Appendix A. Internet Traffic Analysis and Load Balancing Simulation
	Internet traffic [CAIDA] has been analyzed to obtain flow statistics		Internet traffic [CAIDA] has been analyzed to obtain flow statistics
	such as the number of packets in a flow and the flow duration. The		such as the number of packets in a flow and the flow duration. The
	five tuples in the packet header (IP addresses, TCP/UDP Ports, and IP		five tuples in the packet header (IP addresses, TCP/UDP Ports, and IP
	protocol) are used for flow identification. The analysis indicates		protocol) are used for flow identification. The analysis indicates
	that < ~2% of the flows take ~30% of total traffic volume while the		that < ~2% of the flows take ~30% of total traffic volume while the
	rest of the flows (> ~98%) contributes ~70% [YONG].		rest of the flows (> ~98%) contributes ~70% [YONG].
	The simulation has shown that given Internet traffic pattern, the		The simulation has shown that given Internet traffic pattern, the
	hash-based technique does not evenly distribute the flows over ECMP		hash-based technique does not evenly distribute the flows over ECMP
	skipping to change at page 22, line 23		skipping to change at page 22, line 30
	traffic characteristics [YONG].		traffic characteristics [YONG].
	Authors' Addresses		Authors' Addresses
	Ram Krishnan		Ram Krishnan
	Brocade Communications		Brocade Communications
	San Jose, 95134, USA		San Jose, 95134, USA
	Phone: +1-408-406-7890		Phone: +1-408-406-7890
	Email: ramk@brocade.com		Email: ramk@brocade.com
	Sanjay Khanna
	Brocade Communications
	San Jose, 95134, USA
	Phone: +1-408-333-4850
	Email: skhanna@brocade.com
	Lucy Yong		Lucy Yong
	Huawei USA		Huawei USA
	5340 Legacy Drive		5340 Legacy Drive
	Plano, TX 75025, USA		Plano, TX 75025, USA
	Phone: +1-469-277-5837		Phone: +1-469-277-5837
	Email: lucy.yong@huawei.com		Email: lucy.yong@huawei.com
	Anoop Ghanwani		Anoop Ghanwani
	Dell		Dell
	San Jose, CA 95134		San Jose, CA 95134
	Phone: +1-408-571-3228		Phone: +1-408-571-3228
	Email: anoop@alumni.duke.edu		Email: anoop@alumni.duke.edu
	Ning So		Ning So
	Tata Communications		Tata Communications
	Plano, TX 75082, USA		Plano, TX 75082, USA
	Phone: +1-972-955-0914		Phone: +1-972-955-0914
	Email: ning.so@tatacommunications.com		Email: ning.so@tatacommunications.com
			Sanjay Khanna
			Cisco Systems
			Email: sanjakha@gmail.com
	Bhumip Khasnabish		Bhumip Khasnabish
	ZTE Corporation		ZTE Corporation
	New Jersey, 07960, USA		New Jersey, 07960, USA
	Phone: +1-781-752-8003		Phone: +1-781-752-8003
	Email: bhumip.khasnabish@zteusa.com		Email: bhumip.khasnabish@zteusa.com
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