| PCE Working Group | A. Wang |
| Internet-Draft | China Telecom |
| Intended status: Standards Track | B. Khasanov |
| Expires: August 21, 2020 | S. Fang |
| Huawei | |
| C. Zhu | |
| ZTE Corporation | |
| February 18, 2020 |
PCEP Extension for Native IP Network
draft-ietf-pce-pcep-extension-native-ip-05
This document defines the Path Computation Element Communication Protocol (PCEP) extension for Central Control Dynamic Routing (CCDR) based application in Native IP network. The scenario and framework of CCDR in native IP is described in [I-D.ietf-teas-native-ip-scenarios] and [I-D.ietf-teas-pce-native-ip]. This draft describes the key information that is transferred between Path Computation Element (PCE) and Path Computation Clients (PCC) to accomplish the End to End (E2E) traffic assurance in Native IP network under central control mode.
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This Internet-Draft will expire on August 21, 2020.
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Traditionally, Multiprotocol Label Switching Traffic Engineering (MPLS-TE) traffic assurance requires the corresponding network devices support Multiprotocol Label Switching (MPLS) or the complex Resource ReSerVation Protocol (RSVP)/Label Distribution Protocol (LDP) /Segment Routing etc. technologies to assure the End-to-End (E2E) traffic performance. But in native IP network, there will be no such signaling protocol to synchronize the action among different network devices. It is necessary to use the central control mode that described in [RFC8283] to correlate the forwarding behavior among different network devices. Draft [I-D.ietf-teas-pce-native-ip] describes the architecture and solution philosophy for the E2E traffic assurance in Native IP network via Dual/Multi Border Gateway Protocol (BGP) solution. This draft describes the corresponding Path Computation Element Communication Protocol (PCEP) extensions to transfer the key information about peer address list, peer prefix association and the explicit peer route on on-path router.
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 RFC 2119 [RFC2119].
.This document uses the following terms defined in [RFC5440]: PCE, PCEP
The following terms are defined in this document:
Draft [I-D.ietf-pce-pcep-extension-for-pce-controller] introduces the Central Controller's Instructions (CCI) object which is included in the PCInitiate and PCRpt message to transfer the centrally control instruction and status between Path Computation Element (PCE) and Path Computation Clients (PCC). This object is extended to include the construction for native IP solution. Additional Type-Length-Values (TLVs) are defined and included in this extended CCI object.
CCI Object-Class is TBD, should be same as that defined in draft [I-D.ietf-pce-pcep-extension-for-pce-controller]
CCI Object-Type is TBD for Native IP network
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CC-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Optional TLV //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: CCI Object Format
The fields in the CCI object are as follows:
CC-ID: A PCEP-specific identifier for the CCI information. A PCE creates an CC-ID for each instruction, the value is unique within the scope of the PCE and is constant for the lifetime of a PCEP session. The values 0 and 0xFFFFFFFF are reserved and MUST NOT be used.
Flags: Is used to carry any additional information pertaining to the CCI.
Optional TLV: Additional TLVs that are associated with the Native IP construction.
Three new TLVs are defined in this draft:
The Peer Address List TLV is defined to specify the IP address of peer that the received network device should establish the BGP relationship with. This TLV should only be included and sent to the head and end router of the E2E path in case there is no Route Reflection (RR) involved. If the RR is used between the head and end routers, then such information should be sent to head router, RR and end router respectively.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer Num | Resv. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer ID | AT | Resv. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local AS Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer AS Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ETTL | Peer Cookie |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local IP Address(4/16 Bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer IP Address(4/16 Bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Peer Info. |
// (From Peer ID to Peer IP Address) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Peer Address List TLV Format
Type: 2 Bytes, value is TBD.
Length: 2 Bytes, the length of the following fields.
Peer Num : 2 Bytes, Peer Address Number on the advertised router.
Peer-ID: 2 Bytes, to distinguish the different peer pair, will be referenced in Peer Prefix Association, if the PCE use multi-BGP solution for different QoS assurance requirement.
AT: 1 Bytes, Address Type. To indicate the address type of Peer. Equal to 4, if the following IP address of peer is belong to IPv4; Equal to 6 if the following IP address of peer is belong to IPv6.
Resv: 1 Bytes, Reserved for future use.
Local AS Number: 4 Bytes, to indicate the AS number of the Local Peer.
Peer AS Number: 4 Bytes, to indicate the AS number of Remote Peer.
ETTL: 1 Bytes, to indicate the multi hop count for EBGP session. It should be 0 and ignored when Local AS and Peer AS is same.
Peer Cookie: Used for establishing the secure BGP session between two peers. The PCEP client should use the MD5 algorithm to generate the encrypted message.
Local IP Address(4/16 Bytes): IPv4 address of the local router, used to peer with other end router. When AT equal to 4, length is 32bit; when AT equal to 16, length is 128bit.
Peer IP Address(4/16 Bytes): IPv4 address of the peer router, used to peer with the local router. When AT equal to 4, length is 32bit; IPv6 address of the peer when AT equal to 16, length is 128bit;
The Peer Prefix Association TLV is defined to specify the IP prefixes that should be advertised by the corresponding Peer. This TLV should only be included and sent to the head/end router of the end2end path in case there is no RR involved. If the RR is used between the head and end routers, then such information should be sent to head router,RR and end router respectively.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer ID | Prefixes Num |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer Associated IP Prefix sub TLV(Variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Peer Prefix Association TLV Format
Type: 2 Bytes, value is TBD
Length: 2 Bytes, the length of the following fields.
Peer-ID: 2 Bytes, to indicate which peer should be used to advertise the following IP Prefix TLV. This value is assigned in the Peer Address List object and is referred in this object.
Prefixes Num: 2 Bytes, number of prefixes that advertised by the corresponding Peer. It should be equal to number of the following IP prefix sub TLV.
Peer Associated IP Prefix sub TLV: Variable Length, indicate the advertised IP Prefix.
Prefix sub TLV is used to carry the prefix information, which has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AT | Prefix Length | Prefix Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Prefix sub TLV Format
Type: 2 Bytes, value is TBD
Length: 2 Bytes, the length of the following fields.
AT: 1 Byte, Address Type. To indicate the address type of Peer. Equal to 4, if the following "Prefix address" belong to IPv4; Equal to 6 if the following "Prefix address" belong to IPv6.
Prefix Length: 1 Byte, the prefix length. For example, for 10.0.0.0/8, this field will be equal to 8; for 2001:DB8::/32, this field will be equal to 32.
Prefix Value: Variable length, the value of the prefix. For example, for 10.0.0.0/8, this field will be 10.0.0.0; for 2001:DB8::/32, this field will be equal to 2001:DB8::.
The Explicit Peer Route TLV is defined to specify the explicit peer route to the corresponding peer address on each device that is on the E2E assurance path. This TLV should be sent to all the devices that locates on the E2E assurance path that calculated by PCE.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Route Priority| AT | Peer Address(IPv4/IPv6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Hop Address to the Peer(IPv4/IPv6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Explicit Peer Route TLV
Type: 2 Bytes, value is TBD
Length: 2 Bytes, the length of following fields.
Route Priority: 1 Byte, The priority of this explicit route. The higher priority should be preferred by the device.
AT: 1 Byte, Address Type. To indicate the address type of explicit peer route. Equal to 4, if the following peer and next hop address belongs to IPv4; Equal to 6 if the following peer and next hop address belongs to IPv6.
Peer Address: Variable Length, to indicate the peer address.
Next Hop Address to the Peer: Variable Length, to indicate the next hop address to the corresponding peer that indicated by the Peer-ID.
The information transferred in this draft is mainly used for the light weight BGP session setup, the prefix distribution and the explicit route deployment. The planning, allocation and distribution of the peer addresses within IGP should be accomplished in advanced and they are out of the scope of this draft.
Service provider should consider the protection of PCE and their communication with the underlay devices, which is described in document [RFC5440] and [RFC8253]
IANA is requested to allocate new registry for the CCI Object Type:
Object-Type Value CCI Object Name Reference 3 Native IP This document
IANA is requested to confirm the early allocation of the following TLV Type Indicator values within the "PCEP TLV Type Indicator" sub-registry of the PCEP Numbers registry, and to update the reference in the registry to point to this document, when it is an RFC:
Value Meaning Reference --------------------------------------------------------- TBD Peer Address List TLV This document TBD Peer Prefix Association TLV This document TBD Explicit Peer Route TLV This document TBD Prefix sub TLV This document
Thanks Dhruv Dhody for his valuable suggestions and comments.
| [I-D.ietf-teas-native-ip-scenarios] | Wang, A., Huang, X., Qou, C., Li, Z. and P. Mi, "Scenarios and Simulation Results of PCE in Native IP Network", Internet-Draft draft-ietf-teas-native-ip-scenarios-12, October 2019. |