Entropy Labels in MPLS Forwarding draftkompellamplsentropylabel01 Kireeti Kompella

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 IPv 4 or IPv 6 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 When app. labels ARE NOT used When app. labels ARE used Tunnel Label Entropy Label Indicator (ELI) BOS = 0 Application Label BOS = 0 Entropy Label BOS = 1 Entropy Label value Entropy Label BOS = 1 Data Header (e. g. : IPv 4 or IPv 6) Data

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. : IPv 4/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 0 1 2 3 0123456789012345678901 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |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?