Types and Characteristics of Packet
Transport Network (PTN) Equipment
(Draft Recommendation - G.ptneq)
Jia He and Hilmar Hofmann
G.ptneq editors
Geneva, 27 May 2010
Introduction
Since 2002, the ITU-T has been developing
recommendations for packet transport network
architecture, equipment, OAM, NNI, protection and
management with specific emphasis on technology such as
Ethernet and MPLS
The Ethernet recommendations have been developed in a
close cooperation with IEEE 802.1
These recommendations use functional decomposition/
components to describe packet transport networks
Missing today is a recommendation which provides
guidance on how to combine these functional components
in equipment and networks
This gap has been identified and a new recommendation
G.ptneq is a work in progress
Geneva, 27 May 2010
2
G.ptneq: Rationale
The objective is to describe PTN equipment
functionality independent of existing and
future packet based technologies (ie.
generic part)
A second part is to describe technology
specific equipment functionality such as
Ethernet or MPLS-TP.
Enable any PTN equipment to use common
features:
management plane
control plane
survivability schemes
OAM behaviour
PTN equipment built for different packet technologies
shall have common characteristics
Geneva, 27 May 2010
3
G.ptneq: Background
ITU-T develops generic description of
functional reference models for transport
network equipment which are used in a
Packet Transport Network to efficiently
provide packet based services.
The objective is:
To provide a variety of equipment type examples (VC
Term, VC Switch, VP Switch, etc.)
To describe the equipment using atomic functions
To avoid constraints on the implementation
PTN equipment types are described in
terms of functional blocks
Geneva, 27 May 2010
4
G.ptneq: Timetable
Consent a recommendation by June
2010 which contains the basic
concept and generic/technology
agnostic information.
Consent a second version in Feb
2011 which contains additional
technology specific functionality (e.g.
Ethernet, MPLS-TP).
Geneva, 27 May 2010
5
G.ptneq: Scope
This recommendation describes an
overview of the functions of packet
transport network (PTN) equipment
and provides examples of various PTN
equipment types. It is by no means
restricting the way equipment may be
built.
G.ptneq does not mandate the way
equipment should be built.
Geneva, 27 May 2010
6
G.ptneq: Content
Current draft version contains basic
concept and generic/technology agnostic
aspects.
PTN Layer Hierarchy
Functions to be supported on PTN equipment
Multiplexing/Demultiplexing
OAM and provisioning/management
Protection switching
Timing and Synchronization
PTN Interface ports
PTN Equipment types
Geneva, 27 May 2010
7
G.ptneq:
PTN Domain Model
Wholesale
Access Point
UNI
VC
Term
VC
Term
UNI
VC
Switch
VC
Switch
VP
Switch
core
VC
Term
VC
Switch
VC
Switch
Carrier B
IaDI
IaDI
UNI
IrDI
IaDI
IaDI
IaDI
IaDI
VC
Term
UNI
IaDI
VP
Switch
metro
VC Term:
demarcation between
Client and carrier (PTN)
Generation/Termination
of VC layer
VC Switch:
Switch function on VC
layer
Generation/Termination
of VP layer
VP Switch
Switch function on VP
layer
IaDI
UNI
VC
Term
Carrier A
access
Geneva, 27 May 2010
8
G.ptneq:
PTN Layer Hierarchy
PTN provides up to 3
packet based layers
Virtual Channel Layer
Virtual Path Layer (optional)
Transmission Media
Virtual Section Layer (optional)
GFP
Circuit Switching Technology
(OTN, SDH, PDH)
Physical Media
(OTM-n, STM-n, DSn/En,
xDSL)
Geneva, 27 May 2010
Physical Media
(802.3)
PTN layer networks
Path
Channel
Customer/Client service Layer
Virtual Channel Layer
Virtual Path Layer
Virtual Section Layer (as
part of the transmission
media layer)
Client/Server Mode:
customer’s signal is
treated as a client layer
signal of the PTN VC layer
and is encapsulated into
the PTN VC signal
9
G.ptneq:
PTN Layer Hierarchy
Peering Mode
Virtual Channel Layer
Virtual Path Layer (optional)
Transmission Media
Virtual Section Layer (optional)
GFP
Circuit Switching Technology
(OTN, SDH, PDH)
Physical Media
Physical Media
(802.3)
PTN layer networks
Path
Channel
Customer/Client service Layer
customer’s signal is
passed through the
PTN VC layer without
encapsulation
only a subset of
clients that must be of
the same technology
as PTN VC can be
supported
(OTM-n, STM-n, DSn/En,
xDSL)
Geneva, 27 May 2010
10
G.ptneq:
PTN Layer Hierarchy for multiple domains
Domain 1 Domain 2 Domain 3
VC
VP
VC
VS
VP
VC
VS
VP
VS
Geneva, 27 May 2010
In multi-domain case
the layer relationship
is relative.
VP in Domain 1 is VC
Domain 2
VS in Domain 1 is VP
Domain 2
VP in Domain 2 is VC
Domain 3
VS in Domain 2 is VP
Domain 3
in
in
in
in
11
Next Step
PTN VC/VP/VS layers may be supported by the
Ethernet technology including ETH
OAM(Y.1731,G.8021), ETH protection
switching(G.8031,G.8032), ETH connection
management (G.8051, G.8052).
The use of Ethernet technology in PTN requires
an extension of the tagging option defined in
802.1Q to support VC, VP, VS stacking in single
and multi-domain scenarios.
ITU-T Q9/15 would like to progress this work in
cooperation with IEEE 802.1
Geneva, 27 May 2010
12
Thanks You
Any Q?
Backup Slides
G.ptneq:
Generic overview of PTN functional Model
VS/VP-m
VS
PM/VS
PM
VP
MP
MP
MP
MP
MCCS
TP
VS/VC-m
VS
PM/VS
PM
VC
MP
MP
MP
VP
MP MCC
S
TP
MP
MP
VP/VC-m
MP
MCCS
MP
VC
MP
MP MCC
P
VC
TP
VP
VS/VP-m
VS
TP
MP
MP
MP
AVC
MP
MP
AVC
MP
MP
MP
PM
PM/VS
PM
PM/VS
VP
MP
TP
MP
MP
MCCP MP
MP
MCCS MP
MP
MP
TP
MP
MP
MP
MP
MPs
TPs
Geneva, 27 May 2010
VP
VC
MP
VP
MP
VP/VC-m
VC/AVC
MP
VC
AVC
AVP
MP
VP/AV
PM
Sn/AVP
AVP
MP
VC/AVC
AVP
AVP
MP
MCCS MP
VC
MP
MP
TP
VC
MP
VC
Eq/Pqx
Eq
MP
VS
TP
VC/Pqx
MP
VS
MP
VS/VP-m
AVP
MP
VS/VP-m
AVP
MP
VC
ETH
ETY/ETH
ETY
ETH
VC/ETH
PM/VS
PM
MP
VC
EMF
MCF
F
Q
Timing
15
G.ptneq:
Port Model Examples
PTN VC
PTN VC
PTN VC
PTN VC
PTN VC TCMnoMEP
PTN VC TCMnoMEP
PTN VC MIP
PTN VC MIP
PTN VC MIP
PTN VC MIP
mp PTN VC TC
mp PTN VC TC
mp PTN VC VC TC
PTN VC TCMps MEP
mp PTN VC TC
PTN VC TCMps MEP
PTN VC TCMps MEP
mp PTN VC TCM/c MEP
PTN VC TCMps MEP
mp PTN VC TCM/c MEP
mp PTN VC TCM/c MEP
PTN VP NCM MEP
mp PTN VC TCM/c MEP
PTN VP NCM MEP
PTN VS NCM MEP
PTN VS NCM MEP
PTN VS NCM MEP
PTN VS NCM MEP
IrDI Type 1
IaDI Type 1
Geneva, 27 May 2010
IaDI Type 2
IrDI Type 2
16
G.ptneq:
Port Model Examples (contd.)
UNI-N
Service model 1
UNI-N
Service model 2
Client
Client MIP
PTN VC
Client MIP
PTN VC MIP
PTN VC MIP
Client TC
Client specific
processing
PTN VC TC
PTN VC
UNI processing
PTN VC NCMsp MEP
PTN VC TCMsp MEP
PTN VC TCMno MEP
PTN VC TCMno MEP
PTN VC
Geneva, 27 May 2010
ETH VC
17