PCE Working Group H. Chen Internet-Draft Huawei Technologies Intended status: Standards Track January 8, 2017 Expires: July 12, 2017 Native PCE TED draft-chen-pce-pcc-ted-01 Abstract This document presents extensions to the Path Computation Element Communication Protocol (PCEP) for a PCC to advertise the information about the links and for a PCE to build a TED based on the information received. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on July 12, 2017. Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Chen Expires July 12, 2017 [Page 1] Internet-Draft PCE-TED January 2017 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Conventions Used in This Document . . . . . . . . . . . . . . 3 4. Information on Link . . . . . . . . . . . . . . . . . . . . . 3 5. Extensions to PCEP . . . . . . . . . . . . . . . . . . . . . . 4 5.1. Extension to Existing Message . . . . . . . . . . . . . . 4 5.1.1. TLVs . . . . . . . . . . . . . . . . . . . . . . . . . 5 5.1.2. Sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . 6 5.2. Procedures . . . . . . . . . . . . . . . . . . . . . . . . 7 5.2.1. PCC Procedures . . . . . . . . . . . . . . . . . . . . 7 5.2.2. PCE Procedures . . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . . 9 9.2. Informative References . . . . . . . . . . . . . . . . . . 10 Appendix A. New Message . . . . . . . . . . . . . . . . . . . . . 10 A.1. LINK Object . . . . . . . . . . . . . . . . . . . . . . . 10 A.2. TLVs in LINK Object . . . . . . . . . . . . . . . . . . . 11 Chen Expires July 12, 2017 [Page 2] Internet-Draft PCE-TED January 2017 1. Introduction A PCE architecture is described in RFC 4655, in which the TED for a PCE is constructed through using routing protocol such as OSPF or IS-IS running in the domain for which the PCE is resposible. For a domain without running OSPF or IS-IS, the PCE responsible for the domain may obtain the inforamtion about the links from each of the PCCs running on a node in the domain. This document presents extensions to the Path Computation Element Communication Protocol (PCEP) for a PCC to advertise the information about the links attached to the node running the PCC and for a PCE to build a TED based on the information received from the PCC. 2. Terminology The following terminology is used in this document. ABR: Area Border Router. Router used to connect two IGP areas (Areas in OSPF or levels in IS-IS). ASBR: Autonomous System Border Router. Router used to connect together ASes of the same or different service providers via one or more inter-AS links. TED: Traffic Engineering Database. This document uses terminology defined in [RFC5440]. 3. Conventions Used in This Document 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]. 4. Information on Link Since there is no IGP running over any link, we may not obtain the information about the link generated by an OSPF or IS-IS. We may suppose that IP addresses are configured on links. For a point-to-point link connecting two nodes A and B, from A's point of view, the following information about the link may be obtained: Chen Expires July 12, 2017 [Page 3] Internet-Draft PCE-TED January 2017 1) Link Type: Point-to-point 2) Local IP address of the link 3) Remote IP address of the link 4) Traffic engineering metric of the link 5) Maximum bandwidth of the link 6) Maximum reservable bandwidth of the link 7) Unreserved bandwidth of the link 8) Administrative group of the link Note that no link ID (i.e., the Router ID of the neighbor) may be obtained since no IGP adjacency over the link is formed. For a broadcast link connecting multiple nodes, on each of the nodes X, the same information about the link as above may be obtained except for the followings: a) Link Type: Multi-access, b) Local IP address with mask length, and c) No Remote IP address. In other words, the information about the broadcast link obtained by node X comprises a), b), 4), 5), 6), 7) and 8), but does not include any remote IP address or link ID. Note that no link ID (i.e., the interface address of the designated router for the link) may be obtained since no IGP selects it. A PCE constructs a TED for the domain for which the PCE is responsible after receiving the information about each of the links described above from the PCC running on every node in the domain plus the node ID such as A's ID. 5. Extensions to PCEP This section describes the extensions to PCEP to distribute the information about links. 5.1. Extension to Existing Message An existing Notification message may be extended to advertise the information about links. Alternatively, a new message can be used (refer to Appendix A). The following new Notification-type (NT) and Notification-value (NV) of a NOTIFICATION object in a Notification message are defined: Chen Expires July 12, 2017 [Page 4] Internet-Draft PCE-TED January 2017 o NT=8 (TBD): Links * NV=1: Updates on Links. A NT=8 and NV=1 indicates that the PCC sends the PCE updates on the information about Links, and TLVs containing the information are in the NOTIFICATION object. The format and contents of the TLVs are described below. * NV=2: Withdraw Links. A NT=8 and NV=2 indicates that the PCC asks the PCE to remove Links indicated by the TLVs in the object. 5.1.1. TLVs Two TLVs are defined for the information on links. They are link TLV and Router-ID TLV. The format of the link TLV is illustrated below. The Type=tTBD1 indicates a link TLV Type. The Length indicates the size of the Link Sub-TLVs. 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 (tTBD1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Sub-TLVs | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ A link TLV describes a single link. It comprises a number of link sub-TLVs for the information described in section 4, which are the sub-TLVs defined in RFC 3630 or their equivalents except for the local IP address with mask length defined below. The format of the Router-ID TLV is shown below. The Type=tTBD2 indicates a Router-ID TLV Type. The Length indicates the size of the ID and flags field. Chen Expires July 12, 2017 [Page 5] Internet-Draft PCE-TED January 2017 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 (tTBD2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |B|E|I| Flags | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 32-bit/48-bit ID ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Flag B: Set to 1 indicating ABR (B is for Border) Flag E: Set to 1 indicating ASBR (E is for External) Flag I: Set to 1 indicating ID of local router (I is for ID) Undefined flags MUST be set to zero. The ID indicates the ID of a router. For a router not running OSPF or IS-IS, the ID may be the 32-bit or 48-bit ID of the router configured. 5.1.2. Sub-TLVs The format of the Sub-TLV for a local IPv4 address with mask length is shown as follows. The Type=stTBD1 indicates a local IPv4 Address with mask length. The Length indicates the size of the IPv4 address and Mask Length. The IPv4 Address indicates the local IPv4 address of a link. The Mask Length indicates the length of the IPv4 address mask. 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 (stTBD1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mask Length | +-+-+-+-+-+-+-+-+ The format of the Sub-TLV for a local IPv6 address with mask length is illustrated below. The Type=stTBD2 indicates a local IPv6 Address with mask length. The Length indicates the size of the IPv6 address and Mask Length. The IPv6 Address indicates the local IPv6 address of a link. The Mask Length indicates the length of the IPv6 address mask. Chen Expires July 12, 2017 [Page 6] Internet-Draft PCE-TED January 2017 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 (stTBD2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Address (16 bytes) | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mask Length | +-+-+-+-+-+-+-+-+ 5.2. Procedures 5.2.1. PCC Procedures 1. New or Changed Links After the session between a PCC and a PCE is established, the PCC sends the PCE a message containing the information about the links attached to the node running the PCC. When there are changes on the links, the PCC sends the PCE a message for the changed links. For any new or changed links, the PCC sends the PCE a message containing the information about these links with indication of Updates on Links. For example, for a new point-to-point link from node A to node B, the PCC running on node A may send the PCE a Notification message having a NOTIFICATION object with NT=8 and NV=1 (indicating Updates on Links), which contains a Router-ID TLV, followed by a link TLV. The Router-ID TLV comprises the ID of node A and flag I set to 1. The link TLV comprises the Sub-TLVs for the information on 1) to 8) described in section 4. For multiple new or changed links from node A, the PCC running on A may send the PCE a Notification message having a NOTIFICATION object with NT=8 and NV=1, which contains a Router-ID TLV for the ID of node A, followed by multiple link TLVs for the links from node A. Thus this one message contains the information about multiple links. 2. Links Down For any links down, the PCC sends the PCE a message containing the information about these links with indication of Withdraw Links. Chen Expires July 12, 2017 [Page 7] Internet-Draft PCE-TED January 2017 For example, for the point-to-point link from node A to node B down, the PCC running on node A may send the PCE a Notification message having a NOTIFICATION object with NT=8 and NV=2 (indicating Withdraw Links), which contains a Router-ID TLV, followed by a link TLV. The Router-ID TLV comprises the ID of node A and flag I set to 1. The link TLV comprises the Sub-TLVs for the information on 1), 2) and 3) described in section 4. For multiple links from node A down, the PCC running on node A may send the PCE a Notification message having a NOTIFICATION object with NT=8 and NV=2, which contains a Router-ID TLV for the ID of node A, followed by multiple link TLVs for the links from node A. The TLV for a point-to-point link comprises the Sub-TLVs for the information on 1), 2) and 3) described in section 4. The TLV for a broadcast link comprises the Sub-TLVs for the information on a) and b) described in section 4. 3. Simplified Message Alternatively, the messages may be simplified and the PCC procedures may change accordingly. For each node, the source IP address of the PCC running on the node may be used as the ID of the node. The PCE knows the address after the session between the PCE and the PCC is up. When the session between the PCE and the PCC is established, the PCC may send the PCE an ID of the node configured. Thus, a message containing the information about links does not need include any router-ID TLV. For example, for a new point-to-point link attached to node A, the PCC running on node A sends the PCE a Notification message having a NOTIFICATION object with NT=8 and NV=1 (indicating Updates on Links), which contains a link TLV comprising the Sub-TLVs for the information on 1) to 8) described in section 4. The object does not contain any Router-ID TLV for node A. In another example, for multiple links attached to node A down, the PCC running on node A sends the PCE a Notification message having a NOTIFICATION object with NT=8 and NV=2 (indicating Withdraw Links), which contains multiple link TLVs for the links, but does not contain any Router-ID TLV for node A. The TLV for a point-to-point link comprises the Sub-TLVs for the information on 1), 2) and 3) described in section 4. The TLV for a broadcast link comprises the Sub-TLVs for the information on a) and b) described in section 4. Chen Expires July 12, 2017 [Page 8] Internet-Draft PCE-TED January 2017 5.2.2. PCE Procedures A PCE stores the links for each node according to the messages for the links received from the PCC running on the node. For a message containing updates on links, it updates the links accordingly. For a message containing withdraw links, it removes the links. When a node is down, the PCE removes the links attached to the node. After receiving the messages for links from the PCCs, the PCE builds and maintains a TED for the PCE's domain. 6. Security Considerations The mechanism described in this document does not raise any new security issues for the PCEP protocols. 7. IANA Considerations This section specifies requests for IANA allocation. 8. Acknowledgement The authors would like to thank Eric Wu and others for their valuable comments on this draft. 9. References 9.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ RFC2119, March 1997, . [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, DOI 10.17487/ RFC4655, August 2006, . [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, DOI 10.17487/RFC5440, March 2009, . [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, DOI 10.17487/RFC3630, September 2003, Chen Expires July 12, 2017 [Page 9] Internet-Draft PCE-TED January 2017 . 9.2. Informative References [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, . Appendix A. New Message A new message may be defined to advertise the information on links. The format of the message containing the inforamtion on Links (IL for short) is as follows: ::= where: ::= [] Where the value of the Message-Type in the Common Header indicates the new message type. The exact value is to be assigned by IANA. A new RP (NRP) object will be defined, which follows the Common Header. A new flag W (Withdraw) in the NRP object is defined to indicate whether the links are withdrawn. When flag W is set to one, the PCE removes the links contained in the message after receiving it from the PCC. When flag W is set to zero, the PCE adds/updates the links in the message. An alternative to flag W in the NRP object is a similar flag in each LINK object such as using one bit in Res flags for flag W. For example, when the flag is set to one in the object, the PCE removes the links in the object after receiving it. When the flag is set to zero in the object, the PCE adds/updates the links in the object. In another option, one byte in a LINK Object is defined as flags field and one bit is used as flag W. The other undefined bits in the flags field MUST be set to zero. A.1. LINK Object A new object, called LINK Object is defined. The format of LINK object body is as follows: Chen Expires July 12, 2017 [Page 10] Internet-Draft PCE-TED January 2017 Object-Class = ocTBD1 (LINK) Object-Type = 1 (Link) 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |W| Flags | Router-ID TLV | +-+-+-+-+-+-+-+-+ + ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link TLVs | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Router-ID TLV indicates a node in the domain, which is a local end of links. Each of the Link TLVs describes a link and comprises a number of link Sub-TLVs. Flag W=1 indicates withdraw the links. W=0 indicates new or changed links. A.2. TLVs in LINK Object The format of the Router-ID TLV is illustrated below: 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 (tTBD1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 32-bit/48-bit ID ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The format of the link TLV is shown below: 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 (tTBD2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Sub-TLVs | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The link sub-TLVs are for the information on a link described in section 4, which are the sub-TLVs defined in RFC 3630 or their equivalents except for local IP address with mask length. Chen Expires July 12, 2017 [Page 11] Internet-Draft PCE-TED January 2017 Author's Address Huaimo Chen Huawei Technologies Boston, MA, USA EMail: Huaimo.chen@huawei.com Chen Expires July 12, 2017 [Page 12]