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Network Working GroupX. Fu
Internet-DraftX. Lin
Intended status: Standards TrackG. Xie
Expires: September 2, 2010ZTE Corporation
 March 01, 2010


A Framework for Explicit Control of Region Boundary in PCE-Based Inter-Layer Architecture
draft-fuxh-pce-boundary-explicit-control-framework-00

Abstract

This document defines the framework for explicit control of region boundary in PCE-based inter-layer architecture.

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 RFC 2119 (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.) [RFC2119].

Status of this Memo

This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79.

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Copyright Notice

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Table of Contents

1.  Introduction
2.  Explicit Control of Region Boundary
3.  Explicit Control Model of Region Boundary
    3.1.  Explicit Region Control in Single PCE Inter-Layer
    3.2.  Explicit Region Control in Multiple PCE Inter-Layer
4.  Protocol Extension Requirements for Explicit Control of Region Boundary
5.  Security Considerations
6.  IANA Considerations
7.  References
    7.1.  Normative References
    7.2.  Informative References
§  Authors' Addresses



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1.  Introduction

PCE can determine regions' boundaries. Without cooperating with VNTM or policy configuration, a intermediate LSR has to determine regions' boundaries by using the IGP database and ERO as described in [RFC4206] in order to trigger the lower layer signaling. A centralized routing and distributed signaling application is foreseen in the PCE architecture. Without any or enough TED within the intermediate LSR, it could not determine regions' boundaries during the signaling.

This document defines the framework for explicit control of region boundary in PCE-based inter-layer architecture.


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2.  Explicit Control of Region Boundary

PCE can determine regions' boundaries. After PCE compute an end-to-end paths across multi-layer, multi-layer EROs must be carried in PCRep and Path message in terms of RFC5623. In order to explicit control of regions' boundaries, a new object (ERBO- Explicit Region Boundary Object) could be introduced to be carried in PCRep and Path message. Regions' boundaries should be carried in ERBO. [draft-fuxh-ccamp-region-boundary-explicit-control-rsvp-ext-00] defines the RSVP-TE signaling extension for explicit control of region boundary during the signaling procedure. [draft-fuxh-pce-region-boundary-explicit-control-pcep-ext-00] deinfes the PCEP protocol extension for explicit control of region boundary in PCE-based inter-layer architecture.


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3.  Explicit Control Model of Region Boundary


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3.1.  Explicit Region Control in Single PCE Inter-Layer

The process of creating a LSP from H1 to H6 is as follows:

  1. H1 sends a route request to PCE,and PCE responses to H1 with ERO = {H1,H2,L3,L4,H5, H6} and ERBO = {H2,H5}.
  2. H1 Sends Path to H2 with ERO = {H2,L3,L4,H5,H6} and ERBO = {H2, H5}.
  3. After H2 receivs the Path message, H2 confirm that it is the initiator of lower layer LSP in terms of the ERBO, and extracts the complete route of the lower layer LSP in terms of the other end of the region.
  4. Then H2 starts the creation of lower layer LSP, the route is H2,L3,L4,H5.
  5. After the creation of the lower layer LSP, the Higher-Layer LSP's creation is to be continued. And the ERO and ERBO in the Path message is cut out. 


   -----
  | PCE |
   -----
   ^    |
   |  2:PCRep
   |    | (ERO)  (ERBO)
   |    |  ----   ----
   |    | | H1 | | H2 |
   |    |  ----   ----
   |    | | H2 | | H5 |
   |    |  ----   ----
   |    | | L3 |
   |    |  ----
   |    | | L4 |
   |    |  ----
   |    | | H5 |
   |    |  ----
   |    | | H6 |
   |    |  ----
   |    |
1:PCReq |
   |    v
   -----    -----                  -----    -----
  | LSR |--| LSR |................| LSR |--| LSR |
  | H1  |  | H2  |                | H5  |  | H6  |
   -----    -----\                /-----    -----
                  \-----    -----/
                  | LSR |--| LSR |
                  | L3  |  | L4  |
                   -----    -----
 --------------->                --------------->
   3:Path                             4:Path
   (ERO) (ERBO)                       (ERO)
   ----   ----                         ----
  | H2 | | H2 |                       | H2 |
   ----   ----                         ----
  | L3 | | H5 |
   ----   ----
  | L4 |
   ----
  | H5 |
   ----
  | H6 |
   ----

 TOC 

3.2.  Explicit Region Control in Multiple PCE Inter-Layer

The process of creating a LSP from H1 to H10 is as follows:

  1. H1 sends a route request to PCE Ho. PCE Ho computes a multi-layer path with inter-communication with PCE Lo, and responses to H1 with ERO = {H1,H2,L3,M1,M2,L4,H5,H6,L7,L8,H9,H10} and ERBO ={H2,H5,L3,L4,H6,H9}.
  2. H1 Sends Path to H2 with ERO = {H2,L3,M1,M2,L4,H5,H6,L7,L8,H9,H10}, ERBO = {H2,H5,L3,L4,H6,H9}
  3. After H2 receives the Path, H2 is to create lower layer LSP with ERO = {H2,L3,M1,M2,L4,H5}.
  4. H2 Sends Path to L3 with ERO = {L3,M1,M2,L4,H5} and ERBO = {L3,L4}.
  5. After L3 receives the Path, L3 is to create lower layer LSP with ERO = {L3,M1,M2,L4}.
  6. L3 Sends Path to M1 with ERO = {M1,M2,L4} and ERBO = NULL.
  7. After the creation of the lower layer LSP between L3 and L4, L3 continues to send Path to L4 with ERO = {L4,H5} and ERBO = NULL.
  8. After the creation of the lower layer LSP between H2 and H5, H2 continues to send Path to H5 with ERO = {H5,H6,L7,L8,H9,H10} and ERBO = {H6,H9}.
  9. After H6 receives the Path, H6 create the lower layer LSP with ERO = {H6,L7,L8,H9} and ERBO = NULL.
  10. After the creation of the lower layer LSP between H6 and H9, the higher layer LSP's creation is to be continued. 


   -----
  | PCE |
  | Hi  | <----------------------
   -----                        |
   ^    |                       |
   |    |                       |
   |    |                       |
   |    |                       |
   |    |                       |
   |    v                       |
    -----    -----              |                -----    -----                -----    -----
   | LSR |--| LSR |.............|...............| LSR |--| LSR | .............| LSR |--| LSR |
   | H1  |  | H2  |             v               | H5  |  | H6  |              | H9  |  | H10 |
    -----    -----\           -----             /-----    -----\              /-----    -----
                  |          | PCE |            |              |              |
                  |          | Lo  |            |              |              |
                  |           -----             |              |              |
                  \-----                  -----/               \-----    -----/
                  | LSR |................| LSR |               | LSR |..| LSR |
                  | L3  |                | L4  |               | L7  |  | L8  |
                   -----\                /-----                 -----    -----
                        |               |
                        |               |
                        |               |
                        \-----    -----/
                        | LSR |..| LSR |
                        | M1  |  | M2  |
                         -----    -----

The process of creating a LSP from H1 to H10 is as follows:

  1. H1 sends a route request to PCE Ho. PCE Ho computes a multi-layer path without inter-communication with PCE Lo, and responses to H1 with ERO = {H1,H2,M3,M8,H9,H10} and ERBO ={H2,H9}.
  2. H1 Sends Path to H2 with ERO = {H2,M3,M8,H9,H10} and ERBO = {H2,H9}.
  3. After H2 receives the Path, H2 is to create lower layer LSP with ERO = {H2,M3,M8,H9}.
  4. H2 Sends Path to M3,with ERO = {M3,M8,H9} and ERBO = NULL.
  5. M3 consults the PCE Lo with responsibility for the lower-layers network. PCE Lo computes the route to expand the loose hop route (i.e., M3 and M8) in the higher-layer LSP and responses to M3 with ERO = {M3,L4,L5,L6,L7,M8}, ERBO ={L4,L7}.
  6. M3 Sends Path to L4, with ERO = {L4,L5,L6,L7,M8}, ERBO = {L4,L7}.
  7. L4 Sends Path to L5, with ERO = {L5,L6,L7} and ERBO = NULL.
  8. After the creation of the lower layer LSP between L4 and L7, L4 continues to send Path to L7 with ERO = {L7,M8} and ERBO = NULL.
  9. After the creation of the lower layer LSP between M3 and M8, M3 continues to send Path to M8 with ERO = {M8,H9} and ERBO = NULL.
  10. After the creation of the lower layer LSP between H2 and H9, H2 continues to send Path to H9 with ERO = {H9,H10} and ERBO = NUL. 


         -----
        | PCE |
        | Hi  |
         -----
        ^    |
        |    |
        |    |
        |    |
        |    |
        |    v
         -----    -----                                            -----    -----
        | LSR |--| LSR |..........................................| LSR |--| LSR |
        | H1  |  | H2  |                                          | H9  |  | H10 |
         -----    -----\                                          /-----    -----
                       |                                          |
                       |                                          |
                       |                                          |
                       \-----                               -----/
                       | LSR |............................ | LSR |
                       | M3  |<-------------               | M8  |
                        -----\             |               /-----
                             |             v               |
                             |            -----            |
                             |           | PCE |           |
                             |           | Lo  |           |
                             |            -----            |
                              \-----                 -----/
                              | LSR |...............| LSR |
                              | L4  |               | L7  |
                               -----\               /-----
                                    |               |
                                    |               |
                                    |               |
                                    \-----    -----/
                                    | LSR |..| LSR |
                                    | L4  |  | L7  |
                                     -----    -----

 TOC 

4.  Protocol Extension Requirements for Explicit Control of Region Boundary

A requirements for PCRep (RFC5440) extensions to support explicit control of region boundary is foreseen. A requirements for Path (RFC3473) extensions to support explicit control of region boundary is also foreseen. A new object could be introduced in PCRep and Path message. The format of new object is the same as an ERO. [draft-fuxh-pce-region-boundary-explicit-control-pcep-ext-00] deinfes the PCEP protocol extension for explicit control of region boundary in PCE-based inter-layer architecture.


 TOC 

5.  Security Considerations

TBD


 TOC 

6.  IANA Considerations

TBD


 TOC 

7.  References


 TOC 

7.1. Normative References

[RFC2119] Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” BCP 14, RFC 2119, March 1997 (TXT, HTML, XML).
[RFC4206] Kompella, K. and Y. Rekhter, “Label Switched Paths (LSP) Hierarchy with Generalized Multi-Protocol Label Switching (GMPLS) Traffic Engineering (TE),” RFC 4206, October 2005 (TXT).

 TOC 

7.2. Informative References


 TOC 

Authors' Addresses

  Xihua Fu
  ZTE Corporation
  West District,ZTE Plaza,No.10,Tangyan South Road,Gaoxin District
  Xi An 710065
  P.R.China
Phone:  +8613798412242
Email:  fu.xihua@zte.com.cn
URI:  http://wwwen.zte.com.cn/
  
  Xuefeng Lin
  ZTE Corporation
  12F,ZTE Plaza,No.19,Huayuan East Road,Haidian District
  Beijing 100191
  P.R.China
Phone:  +8615901011821
Email:  lin.xuefeng@zte.com.cn
URI:  http://www.zte.com.cn/
  
  Gang Xie
  ZTE Corporation
  12F,ZTE Plaza,No.19,Huayuan East Road,Haidian District
  Beijing 100191
  P.R.China
Phone:  +8613691280432
Email:  xie.gang@zte.com.cn