ECMP for 802.1Qxx

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ECMP for 802.1Qxx

• Proposal for PAR and 5 Criteria
• Version 2
• 16 people from ECMP ad-hoc committee

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Project Authorization Request
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Title

• PAR for an amendment to existing Standard
  802.1Q-2011
• P802.1Qxx
• IEEE Standard for Local and Metropolitan Area
  Networks---Virtual Bridged Local Area Networks
  Amendment Equal Cost
  Multiple Paths (ECMP)

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Scope

• This standard specifies protocols, procedures and
  managed objects to support utilizing multiple
  possible next hop choices for frames within a
  single service in SPBM networks.
• This is accomplished by applying one of a set of
  standard functions per frame at ingress and using
  the result as an input to all subsequent choices
  among multiple next hops as the frame transits
  the SPBM network. These functions are selected to
  ensure that frames belonging to the same data
  flow take the same path.
• It is anticipated that a new Tag will be defined
  possibly including a Time to Live (TTL) field.
• The standard will ensure that Connectivity Fault
  Management (CFM) can be used to proactively
  monitor and diagnose the paths that data takes
  through the network.

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Dependencies

• This standard is dependent on the completion of
  802.1aq.

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Purpose

• .1Qxx provides the additional capability to use
  many more equal cost paths than 802.1aqs current
  ECT mechanism due to improved scaling properties
  with respect to network diameter.
• .1Qxx would be used in conjunction with an
  802.1aq based control plane and would use
  specific B-VIDs and new ECT-ALGORITHMs as defined
  by 802.1aq.
• .1Qxx may include multipath function information
  and may use TTL loop mitigation. Corresponding
  new EtherTypes would identify the new Tag
  formats.
• It is expected that both the current 802.1aq ECT
  and 802.1Qxx ECMP would be used at the same time
  in the same network (for different
  traffic/service categories) but differentiated by
  B-VID.
• 802.1Qxx enhances Connectivity Fault Management
  (CFM) to monitor and diagnose the richer
  connectivity of .1Qxx.

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Need

• As diameter and number of adjacencies grow the
  number of paths increases exponentially. In such
  richly connected networks ECMP in addition to ECT
  allows for better utilization in proportion to
  the state required.
• TTL augments loop mitigation in the face of
  hardware, software and design failures.
• An augmented SPBM with this capability addresses
  urgent customer requests to meet the above needs
  with a single protocol, a single data path and a
  unified OAM suite.

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Stakeholders

• Vendors, users, administrators, designers,
  customers, and owners of Provider Backbone
  Bridged Networks, Carrier Ethernet Networks or
  next generation data centers.

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Other Standards with a Similar Scope

• There are no IEEE standards solving this problem.
• There are other standards (TRILL, VPLS) that
  cover parts of the problem encompassed by
  802.1Qxx but the scope of this standard is more
  complete than any of them.

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Other Questions

• no

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Five Criteria
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Broad Market Potential

• Broad sets of applicability.
• The commercial provision of Ethernet services
  across a Data Center, metropolitan or larger
  networks is large and growing business. Provider
  Backbone Networks are a significant part of this
  market and a required component of the evolving
  Data Center. 802.1Qxx enables even greater use of
  these richer topologies.
• Multiple vendors and numerous users.
• This work is being proposed by a number of major
  vendors representing the majority of current
  users in the market.
• Balanced costs (LAN versus attached stations).
• This project does not materially alter the
  existing cost structure of bridged networks.
  Attached stations would not be aware of the
  operations by transit bridges.

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Compatibility

• IEEE 802 defines a family of standards. All
  standards shall be in conformance with the IEEE
  802.1 Architecture, Management and Inter-working
  documents as follows 802- Overview and
  Architecture, 802.1D, 802.1Q and parts of 802.1f.
  If any variances in conformance emerge, they
  shall be thoroughly disclosed and reviewed with
  802.
• 802.1Qxx would use the 802.1aq SBPM ECT-Algorithm
  framework for forwarding compatibility. This
  guarantees that 802.1Qxx bridges can be added to
  a network of 802.1aq bridges to increment the
  network functionality.
• Each standard in the IEEE 802 family of standards
  shall include a definition of managed objects
  that are compatible with systems management
  standards.
• Such a definition will be included.
• .

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Distinct Identity

• Substantially different from other IEEE 802
  standards.
• This is an amendment to 802.1Q the only standard
  for VLAN aware bridges.
• One unique solution per problem (not two
  solutions to a problem).
• There is currently no general on-data-path
  solution for ECMP forwarded frames.
• Easy for the document reader to select the
  relevant specification.
• This project will amend only the IEEE 802
  standard defining VLAN aware bridges.

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Technical Feasibility

• Demonstrated system feasibility.
• Hash based ECMP is widely deployed in IP networks
  and is well understood. The main issue is one of
  OAM and we will standardize Ethernet solutions
  to OAM issues raised by this new behavior.
• Proven technology, reasonable testing.
• The main concepts are well proven. No unproven
  test technologies are required.
• Confidence in reliability.
• ECMP has wide spread use today with known
  acceptable reliability.
• Coexistence of 802 wireless standards specifying
  devices for unlicensed operation.
• Not applicable

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Economic Feasibility

• Known cost factors, reliable data.
• Minimally this will require either a software
  upgrade to NPU based Ethernet switches, or in the
  case of ASIC based devices a new B-VID behavior
  that mirrors existing 802.1ah with the exception
  of a hash based choice of possible next hops.
  There would therefore be a cost upgrade for ASIC
  based switches.
• Reasonable cost for performance.
• The required hardware and software changes are a
  fraction of the cost of a typical network and
  provide commensurate additional capabilities.
• Consideration of installation costs.
• This functionality can be incrementally
  introduced thus minimizing installation costs.