1. A Lower Effort Per-Hop-Behavior draft-ietf-tsvwg-le-phb-00
Roland Bless,
Karlsruhe Institute of Technology (KIT)
IETF 97
R. Bless, KIT draft-ietf-tsvwg-le-phb

2. R. Bless, KIT draft-ietf-tsvwg-le-phb
Motivation
First idea around since 1999 (lower than best-effort PHB draft-bless-diffserv-lbe-phb)
Main objective: protect best-effort traffic from Lower Effort (LE) traffic
LE for low priority background traffic, e.g., backups, web crawler, game downloads, software updates and OS upgrades
Easy to deploy: no parameters, no traffic conditioning necessary, no trust issues
Internet-2 came up with QBone Scavenger Service 2001
After some discussion in DiffServ WG: RFC 3662 „A Lower Effort Per-Domain Behavior for Differentiated Services“ (2003)
IETF 97
R. Bless, KIT draft-ietf-tsvwg-le-phb

3. R. Bless, KIT draft-ietf-tsvwg-le-phb
Addressed issues
Wrong choice of DiffServ Codepoint (DSCP)
RFC 3662 suggested to re-use AF PHB or CS-1 (Class Selector 1) – normally (by RFC 2474) means better than Best-Effort (BE)
RFC 4594 recommended to use CS-1
Unclear whether CS-1 is actually treated better or worse than Best Effort (BE) in a DS domain
Issues came up with
RTCweb QoS Draft: draft-tsvwg-rtcweb-qos
DiffServ Intercon Draft: draft-tsvwg-diffserv-intercon
IETF 97
R. Bless, KIT draft-ietf-tsvwg-le-phb

4. R. Bless, KIT draft-ietf-tsvwg-le-phb
Discussion (1)
I-D suggests a dedicated DSCP for LE, e.g.,
Removes ambiguity
Is allocated from the DSCP Standards Action pool xxxxx0
Standards Track vs. Experimental
not sure that an experimental RFC can allocate a standard DSCP  that is a main motivation for this I-D
Brian Carpenter suggested the following changes
obsolete RFC 3662 (Lower Effort PDB)
update RFC 4594 (Configuration Guidelines for DiffServ Service classes), explicitly describe changes in LE spec
Need ipr="pre5378Trust200902" waiver
IETF 97
R. Bless, KIT draft-ietf-tsvwg-le-phb

5. R. Bless, KIT draft-ietf-tsvwg-le-phb
Discussion (2)
Remarking recommendation if LE is unsupported: remap DSCP to default PHB (best-effort) handling
Option 1 (suggested): leave DSCP intact as  later traversed domains can treat flow as LE, but service elevation cannot be detected by endpoints
Option 2: remark DSCP to (default PHB)  later traversed domains will treat flow as BE, but different handling can be detect by endpoints
IETF 97
R. Bless, KIT draft-ietf-tsvwg-le-phb