Entropy Labels in MPLS Forwarding draft-kompella-mpls-entropy-label-01

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Entropy Labels in MPLS Forwardingdraft-kompella-m
pls-entropy-label-01

• Kireeti Kompella
• Juniper Networks
• Shane Amante
• Level 3 Communications

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History

• First presented back at IETF 73
• Valuable input ( kick) from John Drake
• Today Update from -00 to -01

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Background

• LAG and ECMP are powerful tools with widespread
  deployment
• Goal is to make them better
• Ingress PEs perform packet header key extraction
  and assigns an entropy label to incoming
  traffic
• Typically, hash of 5-tuple of IPv4 or IPv6 header
• Transit LSRs just use entropy labels as
  input-keys for LAG and ECMP
• Egress PEs discard entropy label before
  forwarding to final destination

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MPLS Label Stack
When app. labels ARE NOT used
When app. labels ARE used
Tunnel Label
Tunnel Label
Application Label BOS 0
Entropy Label Indicator (ELI) BOS 0
Entropy Label value
Entropy Label BOS 1
Entropy Label BOS 1
Data Header (e.g. IPv4 or IPv6)
Data Header (e.g. IPv4 or IPv6)
Data
Data
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Changes from -00 to -01

• Removed reqmt that allowed an LSR to signal it
  MUST receive entropy labels.
• Simplified approach to Entropy Label Indicator
• If application labels are used no ELI necessary
• If no application label is used, (e.g.
  IPv4/MPLS), then ELI MUST always be used for FEC
• Latter makes signaling more straightforward,
  particularly if/when applications are added to
  egress PEs.
• Security Considerations
• IANA Considerations, (see next slide)

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Changes from -00 to -01, (contd)

• LDP Signaling
• Entropy Label sub-TLV
• Label Mapping Msg sub-TLV
• Indicates that egress PE can handle
  entropy-labels
• Indicates label value to use in ELI field

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 ------------
-------------------- UF
Type Length
---------------------
----------- ELI Label

------------------------
-------- Figure 1
Entropy Label sub-TLV
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To Do / Next Steps

• RSVP-TE and BGP signaled entropy labels TBD
• Adopt as WG draft?