Internet DRAFT - draft-paul-pce-dynamic-tunnel
draft-paul-pce-dynamic-tunnel
PCE Arijit Paul
Internet-Draft Juniper Networks
Intended status: Standards Track November 20, 2018
Expires: May 20, 2019
PCEP extension to support reporting of dynamic tunnels
draft-paul-pce-dynamic-tunnel-00
Abstract
In a SDN environment, path computation element protocol(PCEP)
(RFC 5440) is used between a controller and the network devices,
using which controller can setup and tear down Resource ReserVation
Protocol (RSVP) based label switched paths(LSPs) in the network
having Path Computation Client (PCC) as Label Switched Router (LSR).
In an environment where dynamic tunnels are used to provide MPLS based
customer services instead of a Label Switched Path, the specifications
lacks a method to report the Dynamic tunnels over PCEP session to PCE.
This draft defines a method to advertise the dynamic tunnels via PCEP
session to PCE.
This document proposes new object TLV that can be used to report
dynamic tunnels to the PCE.
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
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Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
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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 March 8, 2018
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Conventions used in this document . . . . . . . . . . . . . . 2
3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 2
4. Overview of Protocol Extensions . . . . . . . . . . . . . . . 2
4.1. Capability Advertisement . . . . . . . . . . . . . . . . 2
4.2. Dynamic-Tunnel Object . . . . . . . . . . . . . . . . . 3
4.2.1 IPV4-TUNNEL-IDENTIFIERS TLV . . . . . . . . . . . . . 5
4.3. Metric Object . . . . . . . . . . . . . . . . . . . . . 6
5. Backward Compatibility Consideration . . . . . . . . . . . . 6
6. Management Considerations . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
As described in [RFC5440], PCEP can be used to create, modify or
delete LSPs between PCCs. PCEP can be used to create, modify and
delete RSVP and segment routing LSPs between PCCs. This document
specifies the way to report the dynamic nexthop based tunnels from PCC
to PCE server. This is helpful for PCE to have complete visibility
of the network and help take intelligent decisions based on the
information available to it.
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In this draft a method to report dynamic tunnels from PCC via PCEP is
outlined.
This document proposes one new pcep objects to carry the tunnels attributes
for individual dynamic tunnels. Since only reporting of dynamic tunnels
is outlined here, only dynamic tunnel object and well-known metric objects
are being carried in PCRpt [RFC8231] of PCEP message in order to report
the dynamic tunnel to PCE.
2. 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 [RFC2119].
3. Motivation
PCEP protocol lacks the capability to report dynamic-tunnels e,g,
MPLS over UDP and MPLS over GRE to the PCE. In the SDN scenario
where a controller uses the information provided by PCEP to gain
network visibility, adding the report capability of dynamic-tunnel
via PCEP helps controller gain additional insights about network
tunnels.
4. Overview of Protocol Extensions
4.1. Capability Advertisement
During the PCEP session initialization phase, PCEP speakers (PCE or PCC)
advertise their support of dynamic tunnel report capability. A PCEP
speaker includes the "STATEFUL-PCE-CAPABILITY TLV", described in
Section 7.1.1, in the OPEN object to advertise its support for PCEP
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Stateful PCE extensions. The STATEFUL-PCE-CAPABILITY TLV includes
the 'Dynamic Tunnel Report' flag that indicates whether the PCEP speaker
supports Dynamic Tunnel report capability.
One new flag is added in this document:
D (DYNAMIC-TUNNEL-REPORT bit - TBD): if set to 1 by a PCC, the D Flag
indicates that the PCC is willing to send Dynamic Tunnel State Reports
whenever dynamic tunnel state changes.; if
set to 1 by a PCE, the D Flag indicates that the PCE is interested
in receiving Dynamic Tunnel State Reports whenever dynamic tunnel state changes.
The DYNAMIC-TUNNEL-REPORT Flag must be
advertised by both a PCC and a PCE for PCRpt messages DYNAMIC-TUNNEL-REPORT
extension to be allowed on a PCEP session.
4.2 Dynamic-Tunnel Object
Path Computation State Report (PCRpt): a PCEP message sent by a PCC
to a PCE to report the status of one or more LSPs. Each LSP State
Report in a PCRpt message MAY contain the actual LSP's path,
bandwidth, operational and administrative status, etc. An LSP
Status Report carried on a PCRpt message is also used in
delegation or revocation of control of an LSP to/from a PCE. The
PCRpt message is described in Section 6.1.
One new object is defined in order to report dynamic tunnels to PCE.
The Dynamic-Tunnel object MUST be present within PCRpt messages while
reporting dynamic tunnel. The LSP
object contains a set of fields used to specify the target LSP, the
operation to be performed on the LSP, and LSP delegation. It also
contains a flag indicating to a PCE that the LSP State
Synchronization is in progress. This document focuses on MPLS Tunnels that
run over UDP or GRE.
Dynamic tunnel Object-Class is TBD.
Dynamic tunnel Object-Type is TBD.
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The format of the Dynamic-Tunnel object body is shown in Figure 1:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel-ID | Flag | |O|R|S|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: The LSP Object format
Tunnel-ID (20 bits): A PCEP-specific identifier for the Dynamic Tunnel. A PCC
creates a unique Tunnel-ID for each dynamic tunnel that is constant for the
lifetime of a PCEP session. The PCC will advertise the same Tunnel-ID
on all PCEP sessions it maintains at a given time. There will not be any
name associated with dynamic-tunnel, so no mapping between Tunnel-ID and
tunnel name is maintained. If needed PCE can maintain mapping of Tunnel-ID
with source and destination of dynamic tunnels.
All subsequent PCEP messages then address the LSP by the Tunnel-ID. The
values of 0 and 0xFFFFF are reserved. Note that the Tunnel-ID is a
value that is constant for the lifetime of the PCEP session.
Flags (12 bits), starting from the least significant bit:
S (SYNC - 1 bit): The S flag MUST be set to 1 on each PCRpt sent
from a PCC during State Synchronization. The S flag MUST be set
to 0 in other messages sent from the PCC.
R (Remove - 1 bit): On PCRpt messages, the R flag indicates that the
Dynamic tunnel has been removed from the PCC and the PCE SHOULD remove all
state from its database. Upon receiving an Dynamic tunnel State Report with
the R flag set to 1 for a Dynamic tunnel, the PCE SHOULD
remove all state for the path identified by the IPV4-TUNNEL-IDENTIFIERS
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TLV from its database.
O (Operational - 3 bits): On PCRpt messages, the O field represents
the operational status of the LSP.
The following values are defined:
0 - DOWN: not active.
1 - UP: signaled.
2 - ACTIVE: up and carrying traffic.
3-7 - Reserved: these values are reserved for future use.
Unassigned bits are reserved for future uses. They MUST be set to 0
on transmission.
TLVs that may be included in the Dynamic-Tunnel object are described in the
following sections.
4.2.1 IPV4-TUNNEL-IDENTIFIERS TLV
The format of the IPV4-TUNNEL-IDENTIFIERS TLV is shown in the following
figure:
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=16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Tunnel Source Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Tunnel Destination Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: IPV4-TUNNEL-IDENTIFIERS TLV Format
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The type of the TLV is to be assigned by IANA and it has a fixed
length of 2 octets.
IPv4 Tunnel Source Address: contains the tunnel's source IPv4 address
IPv4 Tunnel Destination Address: contains the tunnel's destination IPv4
address
Tunnel Type: Defines the tunnel type. This draft assigns MPLSoUDP a
numeric value of 1 and MPLSoGRE a numeric value of 2.
4.3 Metric Object
This object is already defined in [RFC5440]. It can be reused and metric
type should be set to value 1 which signifies IGP metric.
5. Backward Compatibility Consideration
A PCE that does not support the new capability will not bring up the session
during initialization phase.
6. Management Considerations
Not needed.
7. Security Considerations
This document raises no new security issues.
8. IANA Considerations
IANA is requested to allocate a Type for this new object to
support dynamic tunnel reporting.
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9. References
9.1. Normative References
[draft-crabbe-pce-pce-initiated-lsp] E. Crabbe, "PCEP Extensions
for PCE-initiated LSP Setup
in a Stateful PCE Model"
[draft-sivabalan-pce-segment-routing] E. Crabbe, "PCEP Extensions
for Stateful PCE"
9.2. Informative References
[RFC4657] Ash, J. and J. Le Roux, "Path Computation Element (PCE)
Communication Protocol Generic Requirements", RFC 4657,
September 2006.
[RFC5440] Le Roux, JL., "Path Computation Element (PCE)
Communication Protocol (PCEP)", RFC 5440, March 2009.
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997
Author's Addresses
Arijit Paul
10214 Parkwood Dr. Apt 5
Cupertino, CA - 95014
USA
Email: arijitp@juniper.net
