Entropy Labels in MPLS Forwarding draft-kompella-mpls-entropy-label-01 Kireeti Kompella Juniper Networks Shane Amante Level 3 Communications

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

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

MPLS Label Stack Data Header (e.g.: IPv4 or IPv6) Data Entropy Label BOS = 1 Entropy Label Indicator (ELI) BOS = 0 When app. labels ARE NOT used Tunnel Label Data Header (e.g.: IPv4 or IPv6) Data Entropy Label BOS = 1 Application Label BOS = 0 Application Label BOS = 0 Tunnel Label Entropy Label value When app. labels ARE used

Changes from -00 to -01 Removed reqm’t 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 PE’s. Security Considerations IANA Considerations, (see next slide)

Changes from -00 to -01, (cont’d) 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 |U|F| Type | Length | | ELI Label | Figure 1: Entropy Label sub-TLV

To Do / Next Steps RSVP-TE and BGP signaled entropy labels TBD Adopt as WG draft?