draft-ietf-teas-pce-native-ip-06.txt   draft-ietf-teas-pce-native-ip-07.txt 
TEAS Working Group A. Wang TEAS Working Group A. Wang
Internet-Draft China Telecom Internet-Draft China Telecom
Intended status: Experimental Q. Zhao Intended status: Experimental B. Khasanov
Expires: November 15, 2020 Etheric Networks Expires: December 3, 2020 Huawei Technologies
B. Khasanov Q. Zhao
Huawei Technologies Etheric Networks
H. Chen H. Chen
Futurewei Futurewei
May 14, 2020 June 1, 2020
PCE in Native IP Network PCE in Native IP Network
draft-ietf-teas-pce-native-ip-06 draft-ietf-teas-pce-native-ip-07
Abstract Abstract
This document defines the framework for traffic engineering within This document defines the framework for traffic engineering within
native IP network, using Dual/Multi-Border Gateway Protocol (BGP) native IP network, using multiple BGP sessions strategy and PCE
sessions strategy and Path Computation Engine (PCE) -based central -based central control architecture.
control architecture.
Status of This Memo Status of This Memo
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This Internet-Draft will expire on November 15, 2020. This Internet-Draft will expire on December 3, 2020.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. CCDR Framework in Simple Topology . . . . . . . . . . . . . . 3
4. CCDR Framework in Simple Topology . . . . . . . . . . . . . . 3 4. CCDR Framework in Large Scale Topology . . . . . . . . . . . 5
5. CCDR Framework in Large Scale Topology . . . . . . . . . . . 5 5. CCDR Multiple BGP Sessions Strategy . . . . . . . . . . . . . 6
6. CCDR Multi-BGP Strategy . . . . . . . . . . . . . . . . . . . 5 6. PCEP Extension for Key Parameters Delivery . . . . . . . . . 8
7. CCDR Framework for Multi-BGP Strategy . . . . . . . . . . . . 6 7. Deployment Consideration . . . . . . . . . . . . . . . . . . 9
8. PCEP Extension for Key Parameters Delivery . . . . . . . . . 7 7.1. Scalability . . . . . . . . . . . . . . . . . . . . . . . 9
9. Deployment Consideration . . . . . . . . . . . . . . . . . . 8 7.2. High Availability . . . . . . . . . . . . . . . . . . . . 9
9.1. Scalability . . . . . . . . . . . . . . . . . . . . . . . 8 7.3. Incremental deployment . . . . . . . . . . . . . . . . . 10
9.2. High Availability . . . . . . . . . . . . . . . . . . . . 8 8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
9.3. Incremental deployment . . . . . . . . . . . . . . . . . 9 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
10. Security Considerations . . . . . . . . . . . . . . . . . . . 9 10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 10
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
12. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 9 11.1. Normative References . . . . . . . . . . . . . . . . . . 11
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 11.2. Informative References . . . . . . . . . . . . . . . . . 12
13.1. Normative References . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
13.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
Draft [RFC8735] describes the scenarios and simulation results for [RFC8735] describes the scenarios and simulation results for traffic
traffic engineering in native IP network. To meet the requirements engineering in native IP network. To meet the requirements of
of various scenarios, the solution for traffic engineering in native various scenarios, the solution for traffic engineering in native IP
IP network should have the following criteria: network should have the following criteria:
o No complex Multiprotocol Label Switching (MPLS) signaling o No complex signaling procedures among network nodes like MPLS-TE.
procedures.
o End to End traffic assurance, determined Quality of Service (QoS) o End to End traffic assurance, determined QoS behavior.
behavior.
o Same deployment method for intra-domain and inter-domain. o Same deployment method for intra-domain and inter-domain.
o No upgrade to forwarding behavior of the router. o No upgrade to forwarding behavior of the router.
o Support native IPv4 and IPv6 traffic in the same solution.
o Can exploit the power of centrally control and flexibility/ o Can exploit the power of centrally control and flexibility/
robustness of distributed control protocol. robustness of distributed control protocol.
o Coping with the differentiation requirements for large amount o Coping with the differentiation requirements for large amount
traffic and prefixes. traffic and prefixes.
o Flexible deployment and automation control. o Flexible deployment and automation control.
This document defines the framework for traffic engineering within This document defines the framework for traffic engineering within
native IP network, using Dual/Multi-BGP session strategy, to meet the native IP network, using multiple BGP session strategy, to meet the
above requirements in dynamical and centrally control mode. The above requirements in dynamical and centrally control mode. The
framework is referred as Central Control Dynamic Routing (CCDR) framework is referred as Central Control Dynamic Routing (CCDR)
framework. The related Path Computation Element Communications framework. It depends on the central control (PCE) element to
Protocol (PCEP) extensions to transfer the key parameters between PCE compute the optimal path for selected traffic, and utilizes the
and the underlying network devices are provided in draft dynamic routing behavior of traditional IGP/BGP protocols to forward
[I-D.ietf-pce-pcep-extension-native-ip]. such traffic.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The control messages between PCE and underlying network node are
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this transmitted via Path Computation Element Communications Protocol
document are to be interpreted as described in RFC 2119 [RFC2119] . (PCEP) protocol. The related PCEP extensions are provided in draft
[I-D.ietf-pce-pcep-extension-native-ip].
3. Terminology 2. Terminology
This document uses the following terms defined in [RFC5440]: PCE, This document uses the following terms defined in [RFC5440]: PCE,
PCEP PCEP
The following terms are used in this document: The following terms are used in this document:
o CCDR: Central Control Dynamic Routing o CCDR: Central Control Dynamic Routing
o E2E: End to End o E2E: End to End
o ECMP: Equal Cost Multi Path o ECMP: Equal Cost Multi Path
o QoS: Quality of Service
o RR: Route Reflector o RR: Route Reflector
o SDN: Software Definition Network o SDN: Software Defined Network
4. CCDR Framework in Simple Topology 3. CCDR Framework in Simple Topology
Figure 1 illustrates the CCDR framework for traffic engineering in Figure 1 illustrates the CCDR framework for traffic engineering in
simple topology. The topology is comprised by four devices which are simple topology. The topology is comprised by four devices which are
SW1, SW2, R1, R2. There are multiple physical links between R1 and SW1, SW2, R1, R2. There are multiple physical links between R1 and
R2. Traffic between IP11(on SW1) and IP21(on SW2) is normal traffic, R2. Traffic between prefix PF11(on SW1) and prefix PF21(on SW2) is
traffic between IP12(on SW1) and IP22(on SW2) is priority traffic normal traffic, traffic between prefix PF12(on SW1) and prefix
that should be treated differently. PF22(on SW2) is priority traffic that should be treated differently.
Only native Interior Gateway Protocol (IGP) /BGP protocol is deployed In Intra-AS scenario, IGP and BGP are deployed between R1 and R2. In
between R1 and R2. The traffic between each address pair may change inter-AS scenario, only native BGP protocol is deployed. The traffic
in real time and the corresponding source/destination addresses of between each address pair may change in real time and the
the traffic may also change dynamically. corresponding source/destination addresses of the traffic may also
change dynamically.
The key ideas of the CCDR framework for this simple topology are the The key ideas of the CCDR framework for this simple topology are the
followings: followings:
o Build two BGP sessions between R1 and R2, via the different o Build two BGP sessions between R1 and R2, via the different
loopback addresses lo0, lo1 on these routers. loopback addresses on these routers.
o Send different prefixes via the established BGP sessions. For o Send different prefixes via the established BGP sessions. For
example, IP11/IP21 via the BGP pair 1 and IP12/IP22 via the BGP example, PF11/PF21 via the BGP session 1 and PF12/PF22 via the BGP
pair 2. session 2.
o Set the explicit peer route on R1 and R2 respectively for BGP next o Set the explicit peer route on R1 and R2 respectively for BGP next
hop of lo0, lo1 to different physical link addresses between R1 hop to different physical link addresses between R1 and R2. Such
and R2. explicit peer route can be set in the format of static route to
BGP peer address, which is different from the route learned from
the IGP protocol.
After the above actions, the traffic between the IP11 and IP21, and After the above actions, the traffic between the PF11 and PF21, and
the traffic between IP12 and IP22 will go through different physical the traffic between PF12 and PF22 will go through different physical
links between R1 and R2, each set of traffic occupies different links between R1 and R2, each set of traffic pass through different
dedicated physical links. dedicated physical links.
If there is more traffic between IP12 and IP22 that needs to be If there is more traffic between PF12 and PF22 that needs to be
assured , one can add more physical links between R1 and R2 to reach assured , one can add more physical links between R1 and R2 to reach
the loopback address lo1(also the next hop for BGP Peer pair2). In the the next hop for BGP session 2. In this cases the prefixes that
this cases the prefixes that advertised by the BGP peers need not be advertised by the BGP peers need not be changed.
changed.
If, for example, there is traffic from another address pair that If, for example, there is traffic from another address pair that
needs to be assured (for example IP13/IP23), and the total volume of needs to be assured (for example prefix PF13/PF23), and the total
assured traffic does not exceed the capacity of the previous volume of assured traffic does not exceed the capacity of the
appointed physical links, one need only to advertise the newly added previously provisioned physical links, one need only to advertise the
source/destination prefixes via the BGP peer pair2. The traffic newly added source/destination prefixes via the BGP session 2. The
between IP13/IP23 will go through the assigned dedicated physical traffic between PF13/PF23 will go through the assigned dedicated
links as the traffic between IP12/IP22. physical links as the traffic between PF12/PF22.
Such decouple philosophy gives network operator flexible control Such decouple philosophy gives network operator flexible control
capability on the network traffic, achieve the determined QoS capability on the network traffic, achieve the determined QoS
assurance effect to meet the application's requirement. No complex assurance effect to meet the application's requirement. No complex
MPLS signal procedures is introduced, the router needs only support signaling procedures like MPLS are introduced, the router needs only
native IP protocol. support native IP and multiple BGP sessions setup via different
loopback addresses.
| BGP Peer Pair2 | +-----+
+------------------+ +----------+ PCE +--------+
|lo1 lo1 | | +-----+ |
| | | |
| BGP Peer Pair1 | | BGP Session 1(lo11/lo21)|
+------------------+ +-------------------------+
IP12 |lo0 lo0 | IP22 | |
IP11 | | IP21 | BGP Session 2(lo12/lo22)|
SW1-------R1-----------------R2-------SW2 +-------------------------+
Links Group PF12 | | PF22
PF11 | | PF21
+---+ +-----+-----+ +-----+-----+ +---+
|SW1+---------+(lo11/lo12)+-------------+(lo21/lo22)+--------------+SW2|
+---+ | R1 +-------------+ R2 | +---+
+-----------+ +-----------+
Figure 1: CCDR framework in simple topology Figure 1: CCDR framework in simple topology
5. CCDR Framework in Large Scale Topology 4. CCDR Framework in Large Scale Topology
When the assured traffic spans across the large scale network, as When the assured traffic spans across the large scale network, as
that illustrated in Figure 2, the Dual-BGP sessions cannot be that illustrated in Figure 2, the multiple BGP sessions cannot be
established hop by hop, especially for the iBGP within one AS. established hop by hop, especially for the iBGP within one AS.
For such scenario, we should consider to use the Route Reflector (RR) For such scenario, we should consider to use the Route Reflector (RR)
to achieve the similar effect. Every edge router will establish two [RFC4456]to achieve the similar effect. Every edge router will
BGP peer sessions with the RR via different loopback addresses establish two BGP sessions with the RR via different loopback
respectively. The other steps for traffic differentiation are same addresses respectively. The other steps for traffic differentiation
as that described in the CCDR framework for simple topology. are same as that described in the CCDR framework for simple topology.
As shown in Figure 2, if we select R3 as the RR, every edge router(R1 As shown in Figure 2, if we select R3 as the RR, every edge router(R1
and R7 in this example) will build two BGP session with the RR. If and R7 in this example) will build two BGP session with the RR. If
the PCE calculates select the dedicated path as R1-R2-R4-R7, then the the PCE selects the dedicated path as R1-R2-R4-R7, then the operator
operator should set the explicit peer routes on these routers should set the explicit peer routes via PCEP protocol on these
respectively, pointing to the BGP next hop (loopback addresses of R1 routers respectively, pointing to the BGP next hop (loopback
and R7, which are used to send the prefix of the assured traffic) to addresses of R1 and R7, which are used to send the prefix of the
the selected forwarding address. assured traffic) to the selected forwarding address.
+----------R3(RR)------------+
| |
SW1-------R1-------R5---------R6-------R7--------SW2
| | | |
+-------R2---------R4--------+
Figure 2: CCDR framework in large scale network +-----+
+----------------+ PCE +------------------+
| +--+--+ |
| | |
| | |
| ++-+ |
+------------------+R3+-------------------+
PF12 | +--+ | PF22
PF11 | | PF21
+---+ ++-+ +--+ +--+ +-++ +---+
|SW1+-------+R1+----------+R5+----------+R6+---------+R7+--------+SW2|
+---+ ++-+ +--+ +--+ +-++ +---+
| |
| |
| +--+ +--+ |
+------------+R2+----------+R4+-----------+
+--+ +--+
Figure 2: CCDR framework in large scale network
6. CCDR Multi-BGP Strategy 5. CCDR Multiple BGP Sessions Strategy
In general situation, different applications may require different In general situation, different applications may require different
QoS criteria, which may include: QoS criteria, which may include:
o Traffic that requires low latency and is not sensitive to packet o Traffic that requires low latency and is not sensitive to packet
loss. loss.
o Traffic that requires low packet loss and can endure higher o Traffic that requires low packet loss and can endure higher
latency. latency.
o Traffic that requires low jitter. o Traffic that requires low jitter.
These different traffic requirements can be summarized in the These different traffic requirements can be summarized in the
following table: following table:
+----------+-------------+---------------+-----------------+ +----------------+-------------+---------------+-----------------+
| Flow No. | Latency | Packet Loss | Jitter | | Prefix Set No. | Latency | Packet Loss | Jitter |
+----------+-------------+---------------+-----------------+ +----------------+-------------+---------------+-----------------+
| 1 | Low | Normal | Don't care | | 1 | Low | Normal | Don't care |
+----------+-------------+---------------+-----------------+ +----------------+-------------+---------------+-----------------+
| 2 | Normal | Low | Dont't care | | 2 | Normal | Low | Dont't care |
+----------+-------------+---------------+-----------------+ +----------------+-------------+---------------+-----------------+
| 3 | Normal | Normal | Low | | 3 | Normal | Normal | Low |
+----------+-------------+---------------+-----------------+ +----------------+-------------+---------------+-----------------+
Table 1. Traffic Requirement Criteria Table 1. Traffic Requirement Criteria
For Flow No.1, we can select the shortest distance path to carry the For Prefix Set No.1, we can select the shortest distance path to
traffic; for Flow No.2, we can select the path that is comprised by carry the traffic; for Prefix Set No.2, we can select the path that
under loading links from end to end; For Flow No.3, we can let all is comprised by under loading links from end to end; For Prefix Set
assured traffic pass the determined single path, no Equal Cost No.3, we can let all assured traffic pass the determined single path,
Multipath (ECMP) distribution on the parallel links is desired. no Equal Cost Multipath (ECMP) distribution on the parallel links is
desired.
It is almost impossible to provide an End-to-End (E2E) path with It is almost impossible to provide an End-to-End (E2E) path with
latency, jitter, packet loss constraints to meet the above latency, jitter, packet loss constraints to meet the above
requirements in large scale IP-based network via the distributed requirements in large scale IP-based network via the distributed
routing protocol, but these requirements can be solved with the routing protocol, but these requirements can be solved with the
assistance of PCE, because the PCE has the overall network view, can assistance of PCE, as that described in [RFC4655] and [RFC8283]
collect real network topology and network performance information because the PCE has the overall network view, can collect real
about the underlying network, select the appropriate path to meet network topology and network performance information about the
various network performance requirements of different traffics. underlying network, select the appropriate path to meet various
network performance requirements of different traffics.
7. CCDR Framework for Multi-BGP Strategy
The framework to implement the CCDR Multi-BGP strategy are the The framework to implement the CCDR Multiple BGP sessions strategy
followings. Here PCE is the main component of the Software are the followings. Here PCE is the main component of the Software
Definition Network (SDN) controller and is responsible for optimal Definition Network (SDN) controller and is responsible for optimal
path computation for priority traffic. path computation for priority traffic.
o SDN controller gets topology and link utilization information from o SDN controller gets topology via BGP-LS[RFC7752] and link
the underlying network. utilization information via existing Network Monitor System (NMS)
from the underlying network.
o PCE calculates the appropriate path upon application's o PCE calculates the appropriate path upon application's
requirements, sends the key parameters to edge/RR routers(R1, R7 requirements, sends the key parameters to edge/RR routers(R1, R7
and R3 in Fig.3) to establish multi-BGP peer sessions and and R3 in Fig.3) to establish multiple BGP sessions and advertises
advertises different prefixes via them. different prefixes via them. The loopback addresses used for BGP
sessions should be planned in advance and distributed in the
domain.
o PCE sends the route information to the routers (R1,R2,R4,R7 in o PCE sends the route information to the routers (R1,R2,R4,R7 in
Fig.3) on forwarding path via PCEP, to build the path to the BGP Fig.3) on forwarding path via PCEP
next-hop of the advertised prefixes. [I-D.ietf-pce-pcep-extension-native-ip], to build the path to the
BGP next-hop of the advertised prefixes.
o If the assured traffic prefixes were changed but the total volume o If the assured traffic prefixes were changed but the total volume
of assured traffic does not exceed the physical capacity of the of assured traffic does not exceed the physical capacity of the
previous E2E path, PCE needs only change the prefixed advertised previous E2E path, PCE needs only change the prefixed advertised
via the edge routers (R1,R7 in Fig.3). via the edge routers (R1,R7 in Fig.3).
o If the volume of assured traffic exceeds the capacity of previous o If the volume of assured traffic exceeds the capacity of previous
calculated path, PCE can recalculate and add the appropriate paths calculated path, PCE can recalculate and add the appropriate paths
to accommodate the exceeding traffic. After that, PCE needs to to accommodate the exceeding traffic. After that, PCE needs to
update on-path routers to build the forwarding path hop by hop. update on-path routers to build the forwarding path hop by hop.
+-------+ +------------+
***********+SDN/PCE+********** | Application|
* +---*---+ * +------+-----+
* / * \ * |
* * * +--------+---------+
PCEP* BGP-LS/SNMP *PCEP +----------+SDN Controller/PCE+-----------+
* * * | +--------^---------+ |
* * \ * / | | |
\ * / * \ */ | | |
\*/-----------R3--------------* PCEP | BGP-LS|PCEP | PCEP
| | | | |
| | | +v-+ |
SW1-------R1-------R5---------R6-------R7--------SW2 +------------------+R3+-------------------+
| | | | PF12 | +--+ | PF22
| | | | PF11 | | PF21
+-------R2---------R4--------+ +---+ +v-+ +--+ +--+ +-v+ +---+
|SW1+-------+R1+----------+R5+----------+R6+---------+R7+--------+SW2|
+---+ ++-+ +--+ +--+ +-++ +---+
| |
| |
| +--+ +--+ |
+------------+R2+----------+R4+-----------+
Figure 3: CCDR framework for Multi-BGP deployment Figure 3: CCDR framework for Multi-BGP deployment
8. PCEP Extension for Key Parameters Delivery 6. PCEP Extension for Key Parameters Delivery
The PCEP protocol needs to be extended to transfer the following key The PCEP protocol needs to be extended to transfer the following key
parameters: parameters:
o Peer addresses pair that is used to build the BGP session o Peer addresses pair that is used to build the BGP session
o Advertised prefixes and their associated BGP session. o Advertised prefixes and their associated BGP session.
o Explicit route information to BGP next hop of advertised prefixes. o Explicit route information to BGP next hop of advertised prefixes.
Once the router receives such information, it should establish the Once the router receives such information, it should establish the
BGP session with the peer appointed in the PCEP message, advertise BGP session with the peer appointed in the PCEP message, advertise
the prefixes that contained in the corresponding PCEP message, and the prefixes that contained in the corresponding PCEP message, and
build the end to end dedicated path hop by hop. build the end to end dedicated path hop by hop.
The explicit route created by PCE has the higher priority than the
route information created by other protocols, including the route
manually configured.
All above dynamically created states (BGP sessions, Prefix advertised
prefix, Explict route) will be cleared once the connection between
the PCE and network devices is interrupted.
Details of communications between PCEP and BGP subsystems in router's Details of communications between PCEP and BGP subsystems in router's
control plane are out of scope of this draft and will be described in control plane are out of scope of this draft and will be described in
separate draft [I-D.ietf-pce-pcep-extension-native-ip] . separate draft [I-D.ietf-pce-pcep-extension-native-ip] .
The reason that we select PCEP as the southbound protocol instead of The reason that we select PCEP as the southbound protocol instead of
OpenFlow, is that PCEP is suitable for the changes in control plane OpenFlow, is that PCEP is suitable for the changes in control plane
of the network devices, while OpenFlow dramatically changes the of the network devices, while OpenFlow dramatically changes the
forwarding plane. We also think that the level of centralization forwarding plane. We also think that the level of centralization
that required by OpenFlow is hardly achievable in SP networks so that required by OpenFlow is hardly achievable in SP networks so
hybrid BGP+PCEP approach looks much more interesting. hybrid BGP+PCEP approach looks much more interesting.
9. Deployment Consideration 7. Deployment Consideration
9.1. Scalability 7.1. Scalability
In CCDR framework, PCE needs only influence the edge routers for the In CCDR framework, PCE needs only influence the edge routers for the
prefixes advertisement via the multi-BGP deployment. The route prefixes advertisement via the multiple BGP sessions deployment. The
information for these prefixes within the on-path routers were route information for these prefixes within the on-path routers were
distributed via the BGP protocol. distributed via the BGP protocol.
For multiple domain deployment, the PCE need only control the edge
router to build multiple eBGP sessions, all other procedures are the
same that in one domain.
Unlike the solution from BGP Flowspec, the on-path router need only Unlike the solution from BGP Flowspec, the on-path router need only
keep the specific policy routes to the BGP next-hop of the keep the specific policy routes to the BGP next-hop of the
differentiate prefixes, not the specific routes to the prefixes differentiate prefixes, not the specific routes to the prefixes
themselves. This can lessen the burden from the table size of policy themselves. This can lessen the burden from the table size of policy
based routes for the on-path routers, and has more expandability when based routes for the on-path routers, and has more expandability when
comparing with the solution from BGP flowspec or Openflow. comparing with the solution from BGP flowspec or Openflow. For
example, if we want to differentiate 1000 prefixes from the normal
traffic, CCDR needs only one explicit peer route in every on-path
router, but the BGP flowspec or Openflow needs 1000 policy routes on
them.
9.2. High Availability 7.2. High Availability
The CCDR framework is based on the distributed IP protocol. If the The CCDR framework is based on the distributed IP protocol. If the
PCE failed, the forwarding plane will not be impacted, as the BGP PCE failed, the forwarding plane will not be impacted, as the BGP
session between all devices will not flap, and the forwarding table session between all devices will not flap, and the forwarding table
will remain unchanged. will remain unchanged.
If one node on the optimal path is failed, the priority traffic will If one node on the optimal path is failed, the priority traffic will
fall over to the best-effort forwarding path. One can even design fall over to the best-effort forwarding path. One can even design
several assurance paths to load balance/hot-standby the priority several assurance paths to load balance/hot-standby the priority
traffic to meet the path failure situation, as done in MPLS Fast traffic to meet the path failure situation.
Reroute (FRR).
For high availability of PCE/SDN-controller, operator should rely on For high availability of PCE/SDN-controller, operator should rely on
existing HA solutions for SDN controller, such as clustering existing HA solutions for SDN controller, such as clustering
technology and deployment. technology and deployment.
9.3. Incremental deployment 7.3. Incremental deployment
Not every router within the network will support the PCEP extension Not every router within the network will support the PCEP extension
that defined in [I-D.ietf-pce-pcep-extension-native-ip] that defined in [I-D.ietf-pce-pcep-extension-native-ip]
simultaneously. simultaneously.
For such situations, router on the edge of domain can be upgraded For such situations, router on the edge of domain can be upgraded
first, and then the traffic can be assured between different domains. first, and then the traffic can be assured between different domains.
Within each domain, the traffic will be forwarded along the best- Within each domain, the traffic will be forwarded along the best-
effort path. Service provider can selectively upgrade the routers on effort path. Service provider can selectively upgrade the routers on
each domain in sequence. each domain in sequence.
10. Security Considerations 8. Security Considerations
The PCE should have the capability to calculate the loop-free E2E A PCE assures calculations of E2E path upon the status of network
path upon the status of network condition and the service condition and the service requirements in real time.
requirements in real time.
The PCE need consider the explicit route deployment order (for The PCE need consider the explicit route deployment order (for
example, from tail router to head router) to eliminate the possible example, from tail router to head router) to eliminate the possible
transient traffic loop. transient traffic loop.
CCDR framework described in this draft puts more requirements on the CCDR framework described in this draft puts more requirements on the
function of PCE and its communication with the underlay devices. function of PCE and its communication with the underlay devices.
Service provider should consider more on the protection of PCE and Service provider should consider more on the protection of PCE and
their communication with the underlay devices, which is described in their communication with the underlay devices, which is described in
document [RFC5440] and [RFC8253] document [RFC5440] and [RFC8253]
CCDR framework does not require the change of forward behavior on the CCDR framework does not require the change of forward behavior on the
underlay devices, then there will no additional security impact on underlay devices, then there will no additional security impact on
the devices. the devices.
11. IANA Considerations 9. IANA Considerations
This document does not require any IANA actions. This document does not require any IANA actions.
12. Acknowledgement 10. Acknowledgement
The author would like to thank Deborah Brungard, Adrian Farrel, The author would like to thank Deborah Brungard, Adrian Farrel,
Vishnu Beeram, Lou Berger, Dhruv Dhody, Raghavendra Mallya , Mike Vishnu Beeram, Lou Berger, Dhruv Dhody, Raghavendra Mallya , Mike
Koldychev, Haomian Zheng, Penghui Mi, Shaofu Peng and Jessica Chen Koldychev, Haomian Zheng, Penghui Mi, Shaofu Peng and Jessica Chen
for their supports and comments on this draft. for their supports and comments on this draft.
13. References 11. References
13.1. Normative References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route
Reflection: An Alternative to Full Mesh Internal BGP
(IBGP)", RFC 4456, DOI 10.17487/RFC4456, April 2006,
<https://www.rfc-editor.org/info/rfc4456>.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440, Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009, DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>. <https://www.rfc-editor.org/info/rfc5440>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>.
[RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
"PCEPS: Usage of TLS to Provide a Secure Transport for the "PCEPS: Usage of TLS to Provide a Secure Transport for the
Path Computation Element Communication Protocol (PCEP)", Path Computation Element Communication Protocol (PCEP)",
RFC 8253, DOI 10.17487/RFC8253, October 2017, RFC 8253, DOI 10.17487/RFC8253, October 2017,
<https://www.rfc-editor.org/info/rfc8253>. <https://www.rfc-editor.org/info/rfc8253>.
[RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An
Architecture for Use of PCE and the PCE Communication
Protocol (PCEP) in a Network with Central Control",
RFC 8283, DOI 10.17487/RFC8283, December 2017,
<https://www.rfc-editor.org/info/rfc8283>.
[RFC8735] Wang, A., Huang, X., Kou, C., Li, Z., and P. Mi, [RFC8735] Wang, A., Huang, X., Kou, C., Li, Z., and P. Mi,
"Scenarios and Simulation Results of PCE in a Native IP "Scenarios and Simulation Results of PCE in a Native IP
Network", RFC 8735, DOI 10.17487/RFC8735, February 2020, Network", RFC 8735, DOI 10.17487/RFC8735, February 2020,
<https://www.rfc-editor.org/info/rfc8735>. <https://www.rfc-editor.org/info/rfc8735>.
13.2. Informative References 11.2. Informative References
[I-D.ietf-pce-pcep-extension-native-ip] [I-D.ietf-pce-pcep-extension-native-ip]
Wang, A., Khasanov, B., Fang, S., and C. Zhu, "PCEP Wang, A., Khasanov, B., Fang, S., and C. Zhu, "PCEP
Extension for Native IP Network", draft-ietf-pce-pcep- Extension for Native IP Network", draft-ietf-pce-pcep-
extension-native-ip-05 (work in progress), February 2020. extension-native-ip-05 (work in progress), February 2020.
Authors' Addresses Authors' Addresses
Aijun Wang Aijun Wang
China Telecom China Telecom
Beiqijia Town, Changping District Beiqijia Town, Changping District
Beijing 102209 Beijing 102209
China China
Email: wangaj3@chinatelecom.cn Email: wangaj3@chinatelecom.cn
Quintin Zhao
Etheric Networks
1009 S CLAREMONT ST
SAN MATEO, CA 94402
USA
Email: qzhao@ethericnetworks.com
Boris Khasanov Boris Khasanov
Huawei Technologies Huawei Technologies
Moskovskiy Prospekt 97A Moskovskiy Prospekt 97A
St.Petersburg 196084 St.Petersburg 196084
Russia Russia
Email: khasanov.boris@huawei.com Email: khasanov.boris@huawei.com
Quintin Zhao
Etheric Networks
1009 S CLAREMONT ST
SAN MATEO, CA 94402
USA
Email: qzhao@ethericnetworks.com
Huaimo Chen Huaimo Chen
Futurewei Futurewei
Boston, MA Boston, MA
USA USA
Email: huaimo.chen@futurewei.com Email: huaimo.chen@futurewei.com
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