1. STPP Simple TDM Pseudowire Protocol
PWE3 – 57th IETF
16 July 2003
Yaakov (J) Stein

2. The Great TDM Battle draft-anavi-tdmoip-00 was prepared for 50th IETF
comparisons presented at 52nd IETF
we have been discussing for > 2 years
several compromises reached
and rejected
… the time has come for a decision
50 Minneapolis
51 London
52 Salt Lake City
53 Minneapolis
54 Yokohama
55 Atlanta
56 San Francisco
57 Vienna

3. draft-anavi-tdmoip-05
Multiple main modes to optimize for special cases
raw (STPP)
AAL1 unstructured, structured, structured w/ CAS
AAL2
HDLC
Various special mechanisms to cope with network defects
adaptive clock recovery
common clock SRTS
packet loss avoidance
packet loss concealment
Simple interworking with existing AAL1 and AAL2 networks

4. draft-vainshtein-cesopsn-06
Evolved into a long complex draft
Single main mode with plethora of submodes
framelength locking OR frame locking
full multiframe in packet OR multiframe marking
RTP OR RTP compressed OR RTP suppressed
T1 octet-aligned OR 8-consectuive frames
optional “ECMP Prevention” protector
signaling packets OR in-packet signaling structure
Support (for which submodes?)

5. STPP Simple (dumb) TDM pseudowire protocol
Draft is only 11 pages, readable by non-TDMers
Designed to cover most common TDM cases
clock available or unimportant
low packet loss
TDM structure unimportant
CAS/CCS signaling unimportant
Simply encapsulate arbitrary length TDM packets
When special sizes are needed, their use is encouraged
default sizes are those needed by CESoPSN implementations
should use sizes that simplify AAL1-interworking if needed
No special payload treatment (e.g. AAL1 buffering or frame-locking)
Highest possible BW efficiency (no extraneous overhead)

6. Proposal Accept STPP for most common (simplest) TDM cases
broad support
easy to implement
Accept both TDMoIP and CESoPSN for special cases
structure critical
CAS signaling
high packet loss
problematic clock recovery
interworking with existing networks
and let the market decide