Internet DRAFT - draft-lee-teas-actn-poi-applicability
draft-lee-teas-actn-poi-applicability
TEAS Working Group Y. Lee
Internet Draft Futurewei
Intended status: Informational
Expires: December 20, 2019 D. Ceccarelli
Ericsson
J. Tantsura
Apstra
June 20, 2019
Applicability of ACTN to Support Packet and Optical Integration
draft-lee-teas-actn-poi-applicability-00
Abstract
This document outlines the applicability of Abstraction and
Control of Traffic Engineered Networks (ACTN) to Packet & Optical
Integration (POI). It also identifies a number of deployment
scenarios to support L3VPN and L2VPN in operator's networks and
provides implementation guidelines.
Status of this Memo
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Copyright Notice
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Table of Contents
1. Introduction.................................................3
1.1. Requirements Language.....................................3
2. POI with L2/L3VPN Service Under Single Network Operator Control
................................................................3
2.1. L2/L3VPN/VN Service Request by the Customer...............5
2.2. Service and Network Orchestration.........................7
2.3. IP/MPLS Domain Controller and NE Functions...............10
2.3.1. Scenario A: Shared Tunnel Selection.................10
2.3.1.1. Domain Tunnel Selection........................11
2.3.1.2. VPN/VRF Provisioning for L3VPN.................12
2.3.1.3. VSI Provisioning for L2VPN.....................13
2.3.1.4. Inter-domain Links Update......................13
2.3.1.5. End-to-end Tunnel Management...................13
2.3.2. Scenario B: Isolated VN/Tunnel Establishment........14
2.4. Optical Domain Controller and NE Functions...............14
2.5. Orchestrator-Controllers-NEs Communication Protocol Flows16
3. POI with VN Recursion Under Multiple Network Operators Control
...............................................................17
3.1. Service Request Process between Multiple Operators.......19
3.2. Service/network Orchestration of Operator 2..............19
4. Security Considerations.....................................20
5. IANA Considerations.........................................21
6. Acknowledgements............................................21
7. References..................................................21
7.1. Normative References.....................................21
7.2. Informative References...................................21
8. Contributors................................................22
Authors' Addresses.............................................22
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1. Introduction
Abstraction and Control of Traffic Engineered Networks (ACTN)
describes a set of management and control functions used to
operate one or more TE networks to construct virtual networks that
can be represented to customers and that are built from
abstractions of the underlying TE networks so that, for example, a
link in the customer's network is constructed from a path or
collection of paths in the underlying networks [RFC8453].
This document outlines the applicability of Abstraction and
Control of Traffic Engineered Networks (ACTN) to Packet and
Optical Integration. It also identifies a number of deployment
scenarios to support POI in operator's networks and provides
implementation guidelines.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL"
in this document are to be interpreted as described in [RFC2119].
2. POI with L2/L3VPN Service Under Single Network Operator Control
This section provides a number of deployment scenarios for packet
and optical integration (POI). Specifically, this section provides
a deployment scenario in which ACTN hierarchy is deployed to
control a multi-layer and multi-domain network via two IP/MPLS
PNCs and two Optical PNCs with coordination with L-MDSC. This
scenario is in the context of an upper layer service configuration
(e.g. L3VPN) across two AS domains which are transported by two
transport underlay domains (e.g. OTN).
The provisioning of the L3VPN service is outside ACTN scope but it
is worth showing how the L3VPN service provisioning is integrated
for the end-to-end service fulfilment in ACTN context. An example
of service configuration function in the Service/Network
Orchestrator is discussed in [bess-l3vpn].
Figure 1 shows an ACTN POI Reference Architecture where it shows
ACTN components as well as non-ACTN components that are necessary
for the end-to-end service fulfilment. Both IP/MPLS and Optical
Networks are multi-domain. Each IP/MPLS domain network is
controlled by its' domain controller and all the optical domains
are controlled by a hierarchy of optical domain controllers. The
L-MDSC function of the optical domain controllers provides an
abstract view of the whole optical network to the Service/Network
Orchestrator. It is assumed that all these components of the
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network belong to one single network operator domain under the
control of the service/network orchestrator.
Customer
+-------------------------------+
| +-----+ +------------+ |
| | CNC |----| Service Op.| |
| +-----+ +------------+ |
+-------|------------------|----+
| ACTN interface | Non-ACTN interface
| CMI | (Customer Service model)
Service/Network| +----------------+
Orchestrator | |
+------|-----------------------------------|-----------+
| +----------------------------------+ | |
| |MDSC TE & Service Mapping Function| | |
| +----------------------------------+ | |
| | | | |
| +------------------+ +---------------------+ |
| | MDSC NP Function |-------|Service Config. Func.| |
| +------------------+ +---------------------+ |
+------|---------------------------|-------------------+
MPI | +---------------------+--+
| / Non-ACTN interface \
+-------+---/-------+------------+ \
IP/MPLS | / |Optical | \ IP/MPLS
Domain 1 | / |Domain | \ Domain 2
Controller| / |Controller | \ Controller
+------|-------/--+ +---|-----+ +--|-----------\----+
| +-----+ +-----+| | +-----+ | |+------+ +------+|
| |PNC1 | |Serv.|| | |PNC | | || PNC2 | | Serv.||
| +-----+ +----- | | +-----+ | |+------+ +------+|
+-----------------+ +---------+ +-------------------+
SBI | | | SBI
v | V
+------------------+ | +------------------+
/ IP/MPLS Network \ | / IP/MPLS Network \
+----------------------+ | SBI +----------------------+
v
+-------------------------------+
/ Optical Network \
+-----------------------------------+
Figure 1. ACTN POI Reference Architecture
Figure 1 shows ACTN POI Reference Architecture where it depicts:
. CMI (CNC-MDSC Interface) interfacing CNC with MDSC function
in the Service/Network Orchestrator. This is where TE &
Service Mapping [TSM] and either ACTN VN [ACTN-VN] or TE-
topology [TE-Topo]model is exchanged over CMI.
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. Customer Service Model Interface: Non-ACTN interface in the
Customer Portal interfacing Service/Network Orchestrator's
Service Configuration Function. This is the interface where
L3SM information is exchanged.
. MPI (MDSC-PNC Interface) interfacing IP/MPLS Domain
Controllers and Optical Domain Controllers.
. Service Configuration Interface: Non-ACTN interface in
Service/Network Orchestrator interfacing with the IP/MPLS
Domain Controllers to coordinate L2/L3VPN multi-domain
service configuration. This is where service specific
information such as VPN, VPN binding policy (e.g., new
underlay tunnel creation for isolation), etc. are conveyed.
. SBI (South Bound Interface): Non-ACTN interface in the domain
controller interfacing network elements in the domain.
Please note that MPI and Service Configuration Interface can be
implemented as the same interface with the two different
capabilities. The split is just functional but doesn't have to be
also logical.
The following sections are provided to describe key functions that
are necessary for the vertical as well as horizontal end-to-end
service fulfilment of POI.
2.1. L2/L3VPN/VN Service Request by the Customer
A customer can request L3VPN services with TE requirements using
ACTN CMI models (i.e., ACTN VN YANG, TE & Service Mapping YANG)
and non-ACTN customer service models such as L2SM/L3SM YANG
together. Figure 2 shows detailed control flow between customer
and service/network orchestrator to instantiate L2/L3VPN/VN
service request.
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Customer
+-------------------------------------------+
| +-----+ +------------+ |
| | CNC |--------------| Service Op.| |
| +-----+ +------------+ |
+-------|------------------------|----------+
2. VN & TE/Svc | | 1.L2/3SM
Mapping | | |
| | ^ | |
| | | | |
v | | 3. Update VN | v
| & TE/Svc |
Service/Network | mapping |
Orchestrator | |
+------------------|------------------------|-----------+
| +----------------------------------+ | |
| |MDSC TE & Service Mapping Function| | |
| +----------------------------------+ | |
| | | | |
| +------------------+ +---------------------+ |
| | MDSC NP Function |-------|Service Config. Func.| |
| +------------------+ +---------------------+ |
+-------|-----------------------------------|-----------+
NP: Network Provisioning
Figure 2. Service Request Process
. ACTN VN YANG provides VN Service configuration, as specified in
[ACTN-VN].
o It provides the profile of VN in terms of VN members, each
of which corresponds to an edge-to-edge link between
customer end-points (VNAPs). It also provides the mappings
between the VNAPs with the LTPs and between the
connectivity matrix with the VN member from which the
associated traffic matrix (e.g., bandwidth, latency,
protection level, etc.) of VN member is expressed (i.e.,
via the TE-topology's connectivity matrix).
o The model also provides VN-level preference information
(e.g., VN member diversity) and VN-level admin-status and
operational-status.
. L2SM YANG [RFC8466] provides all L2VPN service configuration
and site information from a customer/service point of view.
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. L3SM YANG [RFC8299] provides all L3VPN service configuration
and site information from a customer/service point of view.
. The TE & Service Mapping YANG model [TE & Service] provides TE-
service mapping as well as site mapping.
o TE-service mapping provides the mapping of L3VPN instance
from [RFC8299] with the corresponding ACTN VN instance.
o The TE-service mapping also provides the service mapping
requirement type as to how each L2/L3VPN/VN instance is
created with respect to the underlay TE tunnels (e.g.,
whether the L3VPN requires a new and isolated set of TE
underlay tunnels or not, etc.). See Section 2.2 for
detailed discussion on the mapping requirement types.
o Site mapping provides the site reference information
across L2/L3VPN Site ID, ACTN VN Access Point ID, and the
LTP of the access link.
2.2. Service and Network Orchestration
The Service/Network orchestrator shown in Figure 1 interfaces the
customer and decouples the ACTN MDSC functions from the customer
service configuration functions.
An implementation can choose to split the Service/Network
orchestration functions, as described in [RFC8309] and in section
4.2 of [RFC8453], between a top-level Service Orchestrator
interfacing the customer and two low-level Network Orchestrators,
one controlling a multi-domain IP/MPLS network and the other
controlling the Optical networks.
Another implementation can choose to combine the L-MDSC functions
of the Optical hierarchical controller, providing multi-domain
coordination of the Optical network together with the MDSC
functions in the Service/Network orchestrator.
Without loss of generality, this assumes that the service/network
orchestrator as depicted in Figure 1 would include all the
required functionalities as in a hierarchical orchestration case.
One of the important service functions the Service/Network
orchestrator performs is to identify which TE Tunnels should carry
the L3VPN traffic (from TE & Service Mapping Model) and to relay
this information to the IP/MPLS domain controllers, via non-ACTN
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interface, to ensure proper IP/VRF forwarding table be populated
according to the TE binding requirement for the L3VPN.
[Editor's Note: What mechanism would convey on the interface to
the IP/MPLS domain controllers as well as on the SBI (between
IP/MPLS domain controllers and IP/MPLS PE routers) the TE binding
policy dynamically for the L3VPN? Typically, VRF is the function
of the device that participate MP-BGP in MPLS VPN. With current
MP-BGP implementation in MPLS VPN, the VRF's BGP next hop is the
destination PE and the mapping to a tunnel (either an LDP or a BGP
tunnel) toward the destination PE is done by automatically without
any configuration. It is to be determined the impact on the PE VRF
operation when the tunnel is an optical bypass tunnel which does
not participate either LDP or BGP.
Figure 3 shows service/network orchestrator interactions with
various domain controllers to instantiate tunnel provisioning as
well as service configuration.
+-------|----------------------------------|-----------+
| +----------------------------------+ | |
| |MDSC TE & Service Mapping Function| | |
| +----------------------------------+ | |
| | | | |
| +------------------+ +---------------------+ |
| | MDSC NP Function |-------|Service Config. Func.| |
| +------------------+ +---------------------+ |
+-------|------------------------------|---------------+
| |
| +-------------------+------+ 3.
2. Inter-layer | / \ VPN Serv.
tunnel +-----+--------/-------+-----------------+ \provision
binding| / | 1. Optical | \
| / | tunnel creation | \
+----|-----------/-+ +---|------+ +-----|-------\---+
| +-----+ +-----+ | | +------+ | | +-----+ +-----+|
| |PNC1 | |Serv.| | | | PNC | | | |PNC2 | |Serv.||
| +-----+ +-----+ | | +------+ | | +-----+ +-----+|
+------------------+ +----------+ +-----------------+
Figure 3. Service and Network Orchestration Process
. TE binding requirement types [TE-service mapping] are:
1. Hard Isolation with deterministic latency: Customer would
request an L3VPN service [RFC8299] using a set of TE
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Tunnels with a deterministic latency requirement and that
cannot be not shared with other L3VPN services nor compete
for bandwidth with other Tunnels.
2. Hard Isolation: This is similar to the above case without
deterministic latency requirements.
3. Soft Isolation: Customer would request an L3VPN service
using a set of MPLS-TE tunnel which cannot be shared with
other L3VPN services.
4. Sharing: Customer would accept sharing the MPLS-TE Tunnels
supporting its L3VPN service with other services.
For the first three types, there could be additional TE binding
requirements with respect to different VN members of the same VN
associated with an L3VPN service. For the first two cases, VN
members can be hard-isolated, soft-isolated, or shared. For the
third case, VN members can be soft-isolated or shared.
. When "Hard Isolation with or w/o deterministic latency" (i.e.,
the first and the second type) TE binding requirement is
applied for a L3VPN, a new optical layer tunnel has to be
created (Step 1 in Figure 3). This operation requires the
following control level mechanisms as follows:
o The MDSC function of the Service/Network Orchestrator
identifies only the domains in the IP/MPLS layer in which
the VPN needs to be forwarded.
o Once the IP/MPLS layer domains are determined, the MDSC
function of the Service/Network Orchestrator needs to
identify the set of optical ingress and egress points of
the underlay optical tunnels providing connectivity
between the IP/MPLS layer domains.
o Once both IP/MPLS layers and optical layer are determined,
the MDSC needs to identify the inter-layer peering points
in both IP/MPLS domains as well as the optical domain(s).
This implies that the L3VPN traffic will be forwarded to
an MPLS-TE tunnel that starts at the ingress PE (in one
IP/MPLS domain) and terminates at the egress PE (in
another IP/MPLS domain) via a dedicated underlay optical
tunnel.
. The MDSC function of the Service/Network Orchestrator needs to
first request the optical L-MDSC to instantiate an optical
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tunnel for the optical ingress and egress. This is referred to
as optical tunnel creation (Step 1 in Figure 3). Note that it
is L-MDSC responsibility to perform multi-domain optical
coordination with its underlying optical PNCs, for setting up a
multi-domain optical tunnel.
. Once the optical tunnel is established, then the MDSC function
of the Service/Network Orchestrator needs to coordinate with
the PNC functions of the IP/MPLS Domain Controllers (under
which the ingress and egress PEs belong) the setup of a multi-
domain MPLS-TE Tunnel, between the ingress and egress PEs. This
setup is carried by the created underlay optical tunnel (Step 2
in Figure 3).
. It is the responsibility of the Service Configuration Function
of the Service/Network Orchestrator to identify
interfaces/labels on both ingress and egress PEs and to convey
this information to both the IP/MPLS Domain Controllers (under
which the ingress and egress PEs belong) for proper
configuration of the L3VPN (BGP and VRF function of the PEs) in
their domain networks (Step 3 in Figure 3).
2.3. IP/MPLS Domain Controller and NE Functions
IP/MPLS networks are assumed to have multiple domains and each
domain is controlled by IP/MPLS domain controller in which the
ACTN PNC functions and non-ACTN service functions are performed by
the IP/MPLS domain controller.
Among the functions of the IP/MPLS domain controller are VPN
service aspect provisioning such as VRF control and management for
VPN services, etc. It is assumed that BGP is running in the inter-
domain IP/MPLS networks for L2/L3VPN and that the IP/MPLS domain
controller is also responsible for configuring the BGP speakers
within its control domain if necessary.
Depending on the TE binding requirement types discussed in Section
2.2., there are two possible deployment scenarios.
2.3.1. Scenario A: Shared Tunnel Selection
When the L2/L3VPN does not require isolation (either hard or
soft), it can select an existing MPLS-TE and Optical tunnel
between ingress and egress PE, without creating any new TE
tunnels. Figure 4 shows this scenario.
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IP/MPLS Domain 1 IP/MPLS Domain 2
Controller Controller
+------------------+ +------------------+
| +-----+ +-----+ | | +-----+ +-----+ |
| |PNC1 | |Serv.| | | |PNC2 | |Serv.| |
| +-----+ +-----+ | | +-----+ +-----+ |
+--|-----------|---+ +--|-----------|---+
| 1.Tunnel | 2.VPN/VRF | 1.Tunnel |2.VPN/VRF
| Selection | Provisioning | Selection |Provisioning
V V V V
+---------------------+ +---------------------+
CE / PE tunnel 1 ASBR\ /ASBR tunnel 2 PE \ CE
o--/---o..................o--\--------/--o..................o---\-o
\ / \ /
\ AS Domain 1 / \ AS Domain 2 /
+---------------------+ +---------------------+
End-to-end tunnel
<---------------------------------------------------->
Figure 4. IP/MPLS Domain Controller & NE Functions
How VPN is disseminated across the network is out of the scope of
this document. We assume that MP-BGP is running in IP/MPLS
networks and VPN is made known to ABSRs and PEs by each IP/MPLS
domain controllers. See RFC 4364 [RFC4364] for detailed
descriptions on how MP-BGP works.
There are several functions IP/MPLS domain controllers need to
provide in order to facilitate tunnel selection for the VPN in
both domain level and end-to-end level.
2.3.1.1. Domain Tunnel Selection
Each domain IP/MPLS controller is responsible for selecting its
domain level tunnel for the L3VPN. First it needs to determine
which existing tunnels would fit for the L2/L3VPN requirements
allotted to the domain by the Service/Network Orchestrator (e.g.,
tunnel binding, bandwidth, latency, etc.). If there are existing
tunnels that are feasible to satisfy the L3VPN requirements, the
IP/MPLS domain controller selects the optimal tunnel from the
candidate pool. Otherwise, an MPLS tunnel with modified bandwidth
or a new MPLS Tunnel needs to be setup. Note that with no
isolation requirement for the L3VPN, existing MPLS tunnel can be
selected. With soft isolation requirement for the L3VPN, an
optical tunnel can be shared with other L2/L3VPN services while
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with hard isolation requirement for the L2/L3VPN, a dedicated
MPLS-TE and a dedicated optical tunnel MUST be provisioned for the
L2/L3VPN.
2.3.1.2. VPN/VRF Provisioning for L3VPN
Once the domain level tunnel is selected for a domain, the Service
Function of the IP/MPLS domain controller maps the L3VPN to the
selected MPLS-TE tunnel and assigns a label (e.g., MPLS label)
with the PE. Then the PE creates a new entry for the VPN in the
VRF forwarding table so that when the VPN packet arrives to the
PE, it will be able to direct to the right interface and PUSH the
label assigned for the VPN. When the PE forwards a VPN packet, it
will push the VPN label signaled by BGP and, in case of option A
and B [RFC4364], it will also push the LSP label assigned to the
configured MPLS-TE Tunnel to reach the ASBR next hop and forwards
the packet to the MPLS next-hop of this MPLS-TE Tunnel.
In case of option C [RFC4364], the PE will push one MPLS LSP label
signaled by BGP to reach the destination PE and a second MPLS LSP
label assigned to the configured MPLS-TE Tunnel to reach the ASBR
next-hop and forward the packet to the MPLS next-hop of this MPLS-
TE Tunnel.
With Option C, the ASBR of the first domain interfacing the next
domain should keep the VPN label intact to the ASBR of the next
domain so that the ASBR in the next domain sees the VPN packets as
if they are coming from a CE. With Option B, the VPN label is
swapped. With option A, the VPN label is removed.
With Option A and B, the ASBR of the second domain does the same
procedure that includes VPN/VRF tunnel mapping and interface/label
assignment with the IP/MPLS domain controller. With option A, the
ASBR operations are the same as of the PEs. With option B, the
ASBR operates with VPN labels so it can see the VPN the traffic
belongs to. With option C, the ASBR operates with the end-to-end
tunnel labels so it may be not aware of the VPN the traffic
belongs to.
This process is repeated in each domain. The PE of the last domain
interfacing the destination CE should recognize the VPN label when
the VPN packets arrive and thus POP the VPN label and forward the
packets to the CE.
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2.3.1.3. VSI Provisioning for L2VPN
The VSI provisioning for L2VPN is similar to the VPN/VRF provision
for L3VPN. L2VPN service types include:
o Point-to-point Virtual Private Wire Services (VPWSs) that use
LDP-signaled Pseudowires or L2TP-signaled Pseudowires [RFC6074];
o Multipoint Virtual Private LAN Services (VPLSs) that use LDP-
signaled Pseudowires or L2TP-signaled Pseudowires [RFC6074];
o Multipoint Virtual Private LAN Services (VPLSs) that use a Border
Gateway Protocol (BGP) control plane as described in [RFC4761]
And [RFC6624];
o IP-Only LAN-Like Services (IPLSs) that are a functional subset of
VPLS services [RFC7436];
o BGP MPLS-based Ethernet VPN Services as described in [RFC7432]
and [RFC7209];
o Ethernet VPN VPWS specified in [RFC8214] and [RFC7432].
2.3.1.4. Inter-domain Links Update
In order to facilitate inter-domain links for the VPN, we assume
that the service/network orchestrator would know the inter-domain
link status and its resource information (e.g., bandwidth
available, protection/restoration policy, etc.) via some
mechanisms (which are beyond the scope of this document). We also
assume that the inter-domain links are pre-configured prior to
service instantiation.
2.3.1.5. End-to-end Tunnel Management
It is foreseen that the Service/Network orchestrator should
control and manage end-to-end tunnels for VPNs per VPN policy.
As discussed in [ACTN-PM], the Orchestrator is responsible to
collect domain LSP-level performance monitoring data from domain
controllers and to derive and report end-to-end tunnel performance
monitoring information to the customer.
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2.3.2. Scenario B: Isolated VN/Tunnel Establishment
When the L3VPN requires hard-isolated Tunnel establishment,
optical layer tunnel binding with IP/MPLS layer is necessary. As
such, the following functions are necessary.
. The IP/MPLS Domain Controller of Domain 1 needs to send the VRF
instruction to the PE:
o To the Ingress PE of AS Domain 1: Configuration for each
L3VPN destination IP address (in this case the remote CE's
IP address for the VPN or any customer's IP addresses
reachable through a remote CE) of the associated VPN label
assigned by the Egress PE and of the MPLS-TE Tunnel to be
used to reach the Egress PE: so that the proper VRF table
is populated to forward the VPN traffic to the inter-layer
optical interface with the VPN label.
. The Egress PE, upon the discovery of a new IP address, needs to
send the mapping information (i.e., VPN to IP address) to its'
IP/MPLS Domain Controller of Domain 2 which sends, in turn, to
the service orchestrator. The service orchestrator would then
propagate this mapping information to the IP/MPLS Domain
Controller of Domain 1 which sends it, in turn, to the ingress
PE so that it may override the VPN/VRF forwarding or VSI
forwarding, respectively for L3VPN and L2VPN. As a result, when
packets arriving at the ingress PE with that IP destination
address, the ingress PE would then forward this packet to the
inter-layer optical interface.
[Editor's Note: in case of hard isolated tunnel required for the
VPN, we need to create a separate MPLS TE tunnel and encapsulate
the MPLS packets of the MPLS Tunnel into the ODU so that the
optical NE would route this MPLS Tunnel to a separate optical
tunnel from other tunnels.]
2.4. Optical Domain Controller and NE Functions
Optical network provides the underlay connectivity services to
IP/MPLS networks. The multi-domain optical network coordination is
performed by the L-MDSC function shown in Figure 1 so that the
whole multi-domain optical network appears to the service/network
orchestrator as one optical network. The coordination of
Packet/Optical multi-layer and IP/MPLS multi-domain is done by the
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service/network orchestrator where it interfaces two IP/MPLS
domain controllers and one optical L-MDSC.
Figure 5 shows how the Optical Domain Controllers create a new
optical tunnel and the related interaction with IP/MPLS domain
controllers and the NEs to bind the optical tunnel with proper
forwarding instruction so that the VPN requiring hard isolation
can be fulfilled.
IP/MPLS Domain 1 Optical Domain IP/MPLS Domain 2
Controller Controller Controller
+------------------+ +---------+ +------------------+
| +-----+ +-----+ | | +-----+ | | +-----+ +-----+ |
| |PNC1 | |Serv.| | | |PNC | | | |PNC2 | |Serv.| |
| +-----+ +-----+ | | +-----+ | | +-----+ +-----+ |
+--|-----------|---+ +----|----+ +--|----------|----+
| 2.Tunnel | 3.VPN/VRF | |2.Tunnel |3.VPN/VRF
| Binding | Provisioning| |Binding |Provisioning
V V | V V
+-------------------+ | +-------------------+
CE / PE ASBR\ | /ASBR PE \ CE
o--/---o o--\----|--/--o o---\--o
\ : / | \ : /
\ : AS Domain 1 / | \ AS Domain 2 : /
+-:-----------------+ | +-----------------:-+
: | :
: | 1. Optical :
: | Tunnel Creation :
: v :
+-:--------------------------------------------------:-+
/ : : \
/ o..................................................o \
| Optical Tunnel |
\ /
\ Optical Domain /
+------------------------------------------------------+
Figure 5. Domain Controller & NE Functions (Isolated Optical
Tunnel)
. As discussed in 2.2., in case that VPN has requirement for
hard-isolated tunnel establishment, the service/network
orchestrator will coordinate across IP/MPLS domain
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controllers and Optical L-MDSC to ensure the creation of a
new optical tunnel for the VPN in proper sequence. Figure
5 shows this scenario.
o The MDSC of the service/network orchestrator requests
the L-MDSC to setup and Optical tunnel providing
connectivity between the inter-layer interfaces at
the ingress and egress PEs and requests the two
IP/MPLS domain controllers to setup an inter-domain
IP link between these interfaces
o The MDSC of the service/network orchestrator then
should provide the ingress IP/MPLS domain controller
with the routing instruction for the VPN so that the
ingress IP/MPLS domain controller would help its
ingress PE to populate forwarding table. The packet
with the VPN label should be forwarded to the optical
interface the MDSC provided.
The Ingress Optical Domain PE needs to recognize MPLS-TE
label on its ingress interface from IP/MPLS domain PE and
encapsulate the MPLS packets of this MPLS-TE Tunnel into
the ODU.
[Editor's Note: We assumed that the Optical PE is LSR.]
. The Egress Optical Domain PE needs to POP the ODU label
before sending the packet (with MPLS-TE label kept intact
at the top level) to the Egress PE in the IP/MPLS Domain
to which the packet is destined.
[Editor's Note: If there are two VPNs having the same destination
CE requiring non-shared optical tunnels from each other, we need
to explain this case with a need for additional Label to
differentiate the VPNs]
2.5. Orchestrator-Controllers-NEs Communication Protocol Flows
This section provides generic communication protocol flows across
orchestrator, controllers and NEs in order to facilitate the POI
scenarios discussed in Section 2.3.2 for dynamic optical Tunnel
establishment. Figure 6 shows the communication flows.
+---------+ +-------+ +------+ +------+ +------+ +------+
|Orchestr.| |Optical| |Packet| |Packet| |Ing.PE| |Egr.PE|
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| | | Ctr. | |Ctr-D1| |Ctr-D2| | D1 | | D2 |
+---------+ +-------+ +------+ +------+ +------+ +------+
| | | | | |
| | | | |<--BGP--->|
| | | |VPN Update | |
| | | VPN Update|<---------------------|
|<--------------------------------------|(Dest, VPN)| |
| | |(Dest, VPN)| | |
| Tunnel Create | | | | |
|---------------->| | | | |
|(VPN,Ingr/Egr if)| | | | |
| | | | | |
| Tunnel Confirm | | | | |
|<----------------| | | | |
| (Tunnel ID) | | | | |
| | | | | |
| Tunnel Bind | | | | |
|-------------------------->| | | |
| (Tunnel ID, VPN, Ingr if) | Forward. Mapping | |
| | |---------------------->| (1) |
| Tunnel Bind Confirm | (Dest, VPN, Ingr if | |
|<--------------------------| | | |
| | | | | |
| Tunnel Bind | | | | |
|-------------------------------------->| | |
| (Tunnel ID, VPN, Egr if) | | | |
| | | | Forward. Mapping (2)|
| | | |--------------------->|
| | | | (Dest, VPN , Egr if) |
| | Tunnel Bind Confirm | | |
|<--------------------------------------| | |
| | | | | |
Figure 6. Communication Flows for Optical Tunnel Establishment
and binding.
When Domain Packet Controller 1 sends the forwarding mapping
information as indicated in (1) in Figure 6, the Ingress PE in
Domain 1 will need to provision the VRF forwarding table based on
the information it receives. Please see the detailed procedure in
Section 2.3.1.2. A similar procedure is to be done at the Egress
PE in Domain 2.
3. POI with VN Recursion Under Multiple Network Operators Control
[RFC8453] briefly introduces a case for the VN supplied to a
customer may be built using resources from different technology
layers operated by different operators. For example, one operator
may run a packet TE network and use optical connectivity provided
by another operator.
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Figure 7 extracted from [RFC8453] shows the case where a customer
asks for end-to-end connectivity between CE A and CE B, a virtual
network. The customer's CNC makes a request to Operator 1's MDSC.
The MDSC works out which network resources need to be configured
and sends instructions to the appropriate PNCs. However, the link
between Q and R is a virtual link supplied by Operator 2: Operator
1 is a customer of Operator 2.
To support this, Operator 1 has a CNC that communicates with
Operator 2's MDSC. Note that Operator 1's CNC in Figure 10 is a
functional component that does not dictate implementation: it may
be embedded in a PNC.
Virtual CE A o===============================o CE B
Network
----- CNC wants to create
Customer | CNC | a VN between CE A
----- and CE B
:
*********************************************** CMI
:
Operator 1 ---------------------------
| MDSC |
---------------------------
: : :
: : :
----- ------------- -----
| PNC | | PNC | | PNC |
----- ------------- -----
: : : : :
Higher v v : v v
Layer CE A o---P-----Q===========R-----S---o CE B
Network | : |
| : |
| ----- |
| | CNC | | CNC wants to create
| ----- | a VN between Q and R
| : |
*********************************************** CMI
| : |
Operator 2 | ------ |
| | MDSC | |
| ------ |
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| : |
| ------- |
| | PNC | |
| ------- |
\ : : : /
Lower \v v v/
Layer X--Y--Z
Network
Where
--- is a link
=== is a virtual link
Figure 7: VN Recursion with Network Layers
The CMI in Figure 7 interfaces Operator 1's CNC with Operator 2's
MDSC. The functions to perform and the information carried over
the inter-operator CMI are identical to those of the Customer's
CNC and Operator 1's MDSC. In other words, the two CMIs depicted
in Figure 7 are recursive in nature.
3.1. Service Request Process between Multiple Operators
As discussed previously, the reclusiveness principle applies
seamlessly over the two CMIs. This implies that Operator 1's MDSC
needs to pass all customer service requirements transparently to
Operator 2's MDSC so that Operator 2 should provision its underlay
network tunnels to meet the service requirements of the original
customer. The MDSC of Operator 1 should translate/map the original
customer's intent and service requirements and pass down to the
corresponding PNC(s) which is(are) responsible for interfacing
another operator (in this example, Operator 2) that provides
transport services for the segment of the customer's VN. The PNC
in turn performs as a CNC when interfacing its southbound with
Operator 2's MDSC.
It is possible that additional recursive relationships may also
exist between Operator 2 and other operators.
3.2. Service/network Orchestration of Operator 2
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Operator 2 that provides transport service for Operator 1 may also
need to perform service/network orchestration function just as the
case for Operator 1.
4. Security Considerations
From a security and reliability perspective, ACTN may encounter
many risks such as malicious attack and rogue elements attempting
to connect to various ACTN components. Furthermore, some ACTN
components represent a single point of failure and threat vector
and must also manage policy conflicts and eavesdropping of
communication between different ACTN components.
All protocols used to realize the ACTN framework should have rich
security features, and customer, application and network data
should be stored in encrypted data stores. Additional security
risks may still exist. Therefore, discussion and applicability of
specific security functions and protocols will be better described
in documents that are use case and environment specific.
The CMI will likely be an external protocol interface. Suitable
authentication and authorization of each CNC connecting to the
MDSC will be required; especially, as these are likely to be
implemented by different organizations and on separate functional
nodes. Use of the AAA-based mechanisms would also provide role-
based authorization methods so that only authorized CNC's may
access the different functions of the MDSC.
Where the MDSC must interact with multiple (distributed) PNCs, a
PKI-based mechanism is suggested, such as building a TLS or HTTPS
connection between the MDSC and PNCs, to ensure trust between the
physical network layer control components and the MDSC. Trust
anchors for the PKI can be configured to use a smaller (and
potentially non-intersecting) set of trusted Certificate
Authorities (CAs) than in the Web PKI. Which MDSC the PNC exports
topology information to, and the level of detail (full or
abstracted), should also be authenticated, and specific access
restrictions and topology views should be configurable and/or
policy based.
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5. IANA Considerations
This document has no IANA actions.
6. Acknowledgements
The authors thank Adrian Farrel for useful discussions and their
suggestions for this work.
7. References
7.1. Normative References
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[RFC8453] D. Ceccarelli and Y. Lee, "Framework for Abstraction and
Control of Transport Networks", RFC 8453, August 2018.
7.2. Informative References
[bgp-l3vpn] D. Jain, et al. "Yang Data Model for BGP/MPLS L3 VPNs",
draft-ietf-bess-l3vpn-yang, work in progress.
[RFC4364] E. Rosen and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, February 2006.
[RFC4761] K. Kompella, Ed., Y. Rekhter, Ed., "Virtual Private LAN
Service (VPLS) Using BGP for Auto-Discovery and
Signaling", RFC 4761, January 2007.
[ACTN-VN] Y. Lee, et al., "A Yang Data Model for ACTN VN Operation",
draft-ietf-teas-actn-vn-yang, work in progress.
[TSM] Y. Lee, et al., "Traffic Engineering and Service Mapping Yang
Model", draft-ietf-teas-te-service-mapping-yang, work in
progress.
[ACTN-PM] Y. Lee, et al., "YANG models for VN & TE Performance
Monitoring Telemetry and Scaling Intent Autonomics",
draft-lee-teas-actn-pm-telemetry-autonomics, work in
progress.
[TE-Topo] X. Liu, et al., "YANG Data Model for Traffic Engineering
(TE) Topologies", draft-ietf-teas-yang-te-topo, work in
progress.
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[RFC6074] E. Rosen, B. Davie, V. Radoaca, and W. Luo, "Provisioning,
Auto-Discovery, and Signaling in Layer 2 Virtual Private
Networks (L2VPNs)", RFC 6074, January 2011.
[RFC6624] K. Kompella, B. Kothari, and R. Cherukuri, "Layer 2
Virtual Private Networks Using BGP for Auto-Discovery and
Signaling", RFC 6624, May 2012.
[RFC7209] A. Sajassi, R. Aggarwal, J. Uttaro, N. Bitar, W.
Henderickx, and A. Isaac, "Requirements for Ethernet VPN
(EVPN)", RFC 7209, May 2014.
[RFC7432] A. Sajassi, Ed., et al., "BGP MPLS-Based Ethernet VPN",
RFC 7432, February 2015.
[RFC7436] H. Shah, E. Rosen, F. Le Faucheur, and G. Heron, "IP-Only
LAN Service (IPLS)", RFC 7436, January 2015.
[RFC8214] S. Boutros, A. Sajassi, S. Salam, J. Drake, and J.
Rabadan, "Virtual Private Wire Service Support in Ethernet
VPN", RFC 8214, August 2017.
[RFC8309] Q. Wu, W. Liu, and A. Farrel, "Service Model Explained",
RFC 8309, January 2018.
[RFC8299] Q. Wu, S. Litkowski, L. Tomotaki, and K. Ogaki, "YANG Data
Model for L3VPN Service Delivery", RFC 8299, January 2018.
[RFC8466] G. Fioccola, ed., "A YANG Data Model for Layer 2 Virtual
Private Network (L2VPN) Service Delivery", RFC8466,
October 2018.
8. Contributors
Authors' Addresses
Y. Lee
Futurewei Technologies
Email: younglee.tx@gmail.com
D. Ceccarelli
Ericsson
Email: daniele.ceccarelli@ericsson.com
J. Tantsura
Apstra
Email: jefftant.ietf@gmail.com
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