Transcript Interoperability in and Management of a Multi

18 December 2008
Interoperability in and Management
of a Multi-Technology Packet
Transport Network
www.huawei.com
Maarten Vissers
Version 0.0
HUAWEI TECHNOLOGIES Co., Ltd.
Page 1
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Introduction
Our industry has developed three packet transport network technologies to
support transport of frame/packet based service signals as well as bit
stream based service signals and created as such a Multi-Technology PTN
Customer Networks
Custome
r
Network
Multi-Technology
Packet Transport Network
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Customer
Network
Custome
r
Network
PTN
NMS
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PTN Technologies
Ethernet and MPLS packet technologies are extended with a Transport Profile
(TP)
MPLS is extended with a single transport profile, Ethernet is extended with two
transport profiles (with different tunnel layer technologies: VLAN and MAC)
The layer stacks for those three PTN technologies are very similar and
management of these PTN variations can be unified under a single PTN Network
Manager
MPLS-TP
Ethernet-TP (I)
Ethernet-TP (II)
Customer/Client
Customer/Client
Customer/Client
Service VLAN
Service VLAN
MPLS PW
Service VLAN
MPLS Tunnel
(VPLS)
Tunnel VLAN
Tunnel MAC
MPLS Link
Link VLAN
Link VLAN
Physical Media
Physical Media
Physical Media
(802.3,G.707,G.709)
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(802.3,G.707,G.709)
(802.3,G.707,G.709)
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PTN
NMS
PTN Layer Stack & Unified Network Management
ACCESS
NTU
MTU
METRO
Metro
Aggr.
Metro
Edge
CORE
Metro Outer
Core
Core
METRO
Inner
Core
Outer
Core
Metro
Aggr.
Metro
Core
Metro
Edge
Customer/Client layer
PTN Service (Channel) layer
PTN Tunnel (Path) layer
Link (Section) layer
GFP
Physical
Media
Physical
Media
GFP
Physical
Media
Physical
Media
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Physical
Media
GFP
Physical
Media
GFP
Physical
Media
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GFP
Physical
Media
Physical
Media
Services in Multi-Technology PTN
Carrier packet transport networks consists typically of access, metro and core
domains
Access domains typically deploy Ethernet, metro domains deploy Ethernet or
MPLS and core domains deploy MPLS technologies today
The evolution of those packet network technologies into packet transport
network technologies is ongoing for some time
In the near future all three PTN technologies will have the same capabilities and
there is no reason for carriers to deploy a single technology and thus replace
existing equipment
All three PTN technologies can be deployed in every domain (access, metro,
core)
Those multi-technology PTN’s must support inter-domain LINE, TREE and LAN
services, which requires interoperability between the three PTN technologies as
endpoints of each service may be in different PTN technology domains
Such interoperability is required between the service (channel) layers in the three
technologies; interoperability between tunnel (path) and link (section) layers in
the three technologies is not required
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PTN Interoperability for E-TREE/E-LAN services
All three PTN technologies deploy a service VLAN to support E-TREE and
E-LAN services
Interoperability for those services is as such guaranteed; main difference
is the tag/label used to identify each service VLAN
 MPLS-TP: PW label, Ethernet-TP (I): VID, Ethernet-TP (II): SID
UNI
Ethernet-TP (I)
Ethernet-TP (II)
MPLS-TP
Customer/Client: TREE or LAN service
rmp or mp2mp service VLAN
VID
p2p tunnel VLAN
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SID
p2p tunnel MAC
(VPLS)
PW label
p2p MPLS tunnel
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UNI
PTN Interoperability for LINE/TREE services
Two out of three PTN technologies deploy a service VLAN to support LINE and
TREE services, one technology deploys MS-PW
Interoperability for those services requires service VLAN to MS-PW interworking
(as per clause 5.5/G.805 “layer network interworking”)
 ETH/MPLS PW InterWorking function provides such interworking
 Similar OAM PDU formats and similar client encapsulations make interworking trivial
UNI
Ethernet-TP (I)
Ethernet-TP (II)
MPLS-TP
Customer/Client: LINE or TREE service
p2p or p2mp service VLAN
VID
p2p tunnel VLAN
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SID
p2p tunnel MAC
Clause 5.5/G.805 Inter
Working Function
p2p or p2mp PW
PW label
p2p MPLS tunnel
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UNI
Clause 5.5/G.805 Layer Network Interworking
The objective of layer network interworking is to provide an end-to-end trail between
different types of layer network trail terminations. This requires interworking of
characteristic information as different layer networks have per definition different
characteristic information. In general the adapted information of different layer networks
for the same client layer network is also different, although this is not necessarily the case.
Layer networking may therefore require the interworking of adapted information.
The trail overhead of a layer network can be defined in terms of semantics and syntax.
Provided that the same semantics exist in two layer networks, the trail overhead can be
interworked by passing on the semantics from one layer network to the other in the
appropriate syntax, as defined by the characteristic information. In other words layer
network interworking shall be transparent for the semantics of the trail overhead. If both
layer networks have a different set of semantics, the layer network interworking is
restricted to the common set of semantics. The layer network interworking function has to
terminate (insert, supervise) the semantics that are not interworked.
Layer network interworking is accomplished through an interworking processing function
as depicted in Figure 19. The interworking processing function supports an interworking
link connection between two layer network connections. The interworking link connection
is special in the sense that it is asymmetric, delimited by different types of ports. It is also
special because it is in general, only transparent for a specified set of client layers. An
interworking link is a topological component that represents a bridge between two layer
networks. The interworking link creates a "super layer network", defined by the complete
set of access groups that can be interworked for a specified set of client layer networks.
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Example 1: TDM service
A TDM (e.g. 2 Mbit/s) LINE service is supported in Ethernet (MEF8) and
MPLS (RFC4553). Both encapsulation methods are similar, which
simplifies interworking of the adapted information.
ECID format is same as PW label format to
ease interworking with MPLS according MEF8
OAM interworking, see slide 11
ETH OAM
MPLS-TP OAM
Transmitted DA = Received SA or broadcast address
Transmitted SA = local MAC address
G.8021 ETH_AI
20
ID
3 1
8
000 1 00000010
Transmitted ECID = Received PW label stack entry
DA
SA
TYPE (88-d8)
ECID (fixed)
CESoETH CW
RTP (optional)
E
T
H

P
W
Transmitted S-bit = Received ECID[23]
MPLS-TP PW_AI
S bit (1)
SAToP CW
RTP (optional)
TDM payload
TDM payload
UNI
UNI
2 Mbit/s (P12x_CI) service
p2p service VLAN
ETH
ETHPW
p2p MS-PW
p2p tunnel VLAN
p2p tunnel MAC
p2p MPLS tunnel
Ethernet-TP (I)
Ethernet-TP (II)
MPLS-TP
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PW
Example 2: E-LINE service
An Ethernet LINE service is supported in Ethernet and MPLS (RFC4558).
Both encapsulation methods are similar, which simplifies interworking of
the adapted information.
OAM interworking, see slide 11
ETH OAM
MPLS-TP OAM
E
T
H

P
W
Transmitted S-bit = 1
Required in MPLS-TP MS-PW due to
MPLS-TP OAM presence; Seq Number
support is not required; SN = fixed to 0
MPLS-TP PW_AI
S bit (1)
G.8021 ETH_AI
DA
SA
CW (fixed to all-0’s)
DA
SA
MSDU
MSDU
UNI
UNI
E-LINE (ETH_CI) service
p2p service VLAN
ETH
ETHPW
p2p MS-PW
p2p tunnel VLAN
p2p tunnel MAC
p2p MPLS tunnel
Ethernet-TP (I)
Ethernet-TP (II)
MPLS-TP
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PW
Example 1&2: ETH and MPLS-TP PW NCM OAM
interworking
For Network Connection Monitoring (highest MEG level) it is necessary to interwork the
OAM PDU Header and Payload fields. The Header fields for both technologies are known
and interworking is illustrated in figure below. The Payload fields of the MPLS-TP OAM are
not yet specified; if those are a copy of the ETH OAM PDU Payload fields, then interworking
becomes trivial.
Transmitted DA = multicast address or for LBM
TargetMIP/MEP address
G.8021 ETH_CI (OAM)
OAM PDU
independent
Header
OAM PDU
specific
Payload
DA
SA
TYPE (89-02)
MEL (NCM: 7)
5-bit Version
OpCode
Flags
TLV Offset
Transmitted SA = local MAC address or for LBM
OriginatingMEP address
MIP or MEP identifier for Loopback OAM
E
T
H

P
W
MPLS-TP PW_CI (OAM)
S bit (1)
0001
4-bit Version
Reserved
Channel Type
To Be Defined
(e.g. copy of
ETH OAM)
OAM specific
EndTLV
UNI
OAM PDU
specific
Payload
UNI
E-LINE (ETH_CI) service
ETH
OAM PDU
independent
Header
p2p service VLAN
ETHPW
p2p PW
NCM-MEG
NCM-MEG
p2p tunnel VLAN
p2p tunnel MAC
p2p MPLS tunnel
Ethernet-TP (I)
Ethernet-TP (II)
MPLS-TP
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NCM-MEG
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PW
Example 1&2: ETH and MPLS-TP PW TCM OAM
interworking
For Tandem Connection Monitoring (intermediate MEG level) it is necessary to
interwork the OAM PDU Header and Payload fields. The Header fields for both
technologies are known and interworking is illustrated in figure below. The
difference with the NCM OAM is the presence of a Label_13 GAL header.
G.8021 ETH_CI (OAM)
E
T
H

P
W
DA
SA
TYPE (89-02)
MEL (TCM: 1..6)
5-bit Version
OpCode
Flags
TLV Offset
E-NNI
Label_13 GAL
0001
4-bit Version
Reserved
Channel Type
EndTLV
p2p service VLAN
NCM-MEG
ETHPW
NCM-MEG
ETH
TCM-MEG
p2p PW
NCM-MEG
TCM-MEG
Ethernet-TP (I)
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Ethernet-TP (II)
p2p MPLS tunnel
Page 12MPLS-TP
PW
TCM-LSP
p2p tunnel VLAN
p2p tunnel MAC
ACH
UNI
E-LINE (ETH_CI) service
ETH
one GAL header
for PW TCM
To Be Defined
OAM specific
UNI
MPLS-TP PW_CI (OAM)
Conclusion
Interworking between ETH_CI and MPLS-TP PW_CI is an example of
G.805 Layer Network Interworking
The addition of ETH/MPLS-TP PW interworking functions at the
boundaries of Ethernet-TP and MPLS-TP domains reduces PTN network
management complexity and reduces also complexity of UNI-N ports in
MPLS-TP equipment
Interworking of ETH_AI and MPLS-TP PW_AI is trivial (i.e. not complex)
due to common encapsulation methods of client signals
Interworking between ETH_CI and MPLS-TP PW_CI will become trivial
when MPLS-TP OAM re-uses as much as possible the Ethernet OAM PDU
Payload formats
Re-use of Ethernet OAM PDU payload formats has the additional
advantage that existing (Ethernet OAM) hardware, firmware and software
can be re-used, making MPLS-TP OAM available quickly
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