Internet DRAFT - draft-jc-pwe3-mpls-tp-static-checking
draft-jc-pwe3-mpls-tp-static-checking
Network Working Group L. Jin
Internet-Draft R. Chen
Intended status: Standards Track ZTE
Expires: September 5, 2012 March 4, 2012
Static pseudowire configuration checking using Generic Associated
Channel (G-ACh) Advertisement Protocol
draft-jc-pwe3-mpls-tp-static-checking-00.txt
Abstract
This draft introduces a way to do static pseudowire configuration
checking, so as to easy the trouble shooting of static PW in MPLS-TP.
The idea is to use Generic Associated Channel (G-ACh) Advertisement
Protocol (GAP) [I-D.ietf-mpls-gach-adv] in underlying PSN Tunnel to
transfer PW configuration parameters, to achieve static PW
configuration checking.
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 September 5, 2012.
Copyright Notice
Copyright (c) 2012 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
Jin & Chen Expires September 5, 2012 [Page 1]
Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. GAP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Message Encoding . . . . . . . . . . . . . . . . . . . . . 3
3.2. PE Procedure . . . . . . . . . . . . . . . . . . . . . . . 5
3.2.1. PE message processing . . . . . . . . . . . . . . . . . 5
3.2.2. PW Configuration Check Process . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative references . . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
Jin & Chen Expires September 5, 2012 [Page 2]
Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012
1. Introduction
This draft introduces a way to do static pseudowire configuration
checking, so as to easy the trouble shooting of static PW in MPLS-TP.
The idea is to use Generic Associated Channel (G-ACh) Advertisement
Protocol (GAP) [I-D.ietf-mpls-gach-adv] in underlying PSN Tunnel to
transfer PW configuration parameters, to achieve static PW
configuration checking. A precondition of this functionality is that
the underlying PSN Tunnel is already operational, and with GAP
enabled.
2. Motivation
The manual configuration of static PW in MPLS-TP requires configuring
many parameters at two PE sides, and these parameters should be
aligned, so as to make PW be operational. If one of the parameters
on the two PE mis-matching, the PW would not operate correctly. For
the dynamic PW, the parameters would be negotiated by signaling
session, and easy to find out the configuration error if PW is not
operational UP. But for static PW, there is no such kind of
signaling session, it is difficult for operators to do trouble
shooting, to figure out which parameters mis-match at two PE sides.
In order to ease the trouble shooting of static PW, this draft relies
on GAP running on underlying PSN Tunnel to transfer PW configuration
parameters, so as to check PW configuration parameters automatically
on each PE to figure out parameter mis-matching.
3. GAP Extensions
3.1. Message Encoding
A new GAP application "static PW checking" is defined in this draft.
The default lifetime would be 120 seconds. Two new TLV objects
"local static PW element" and "remote static PW element" are defined
for this application, see the format below.
Jin & Chen Expires September 5, 2012 [Page 3]
Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW Element | Reserved | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Generalized ID FEC +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Parameters |
| " |
| " |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Incoming Label (0x0200) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Outgoing Label (0x0200) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
Local static PW element type: to be assigned by IANA.
Remote static PW element type: to be assigned by IANA.
The value of "local&remote static PW element" TLV should carry local
static PW configuration and remote static PW configuration
separately. Multiple "local&remote static PW element" TLVs could be
included in "static PW configuration" application data block.
The value of "local&remote static PW element" TLV object would
include:
1. Generalized PWid FEC (type 129) [RFC4447] along with AII Type 2
[RFC5003];
2. Interface parameters TLV for Generalized PWid FEC defined in
[RFC4447];
3. Incoming and outgoing generic label as defined in [RFC5036];
The Generalized PWid FEC and incoming generic label MUST be included
in static PW element. The Incoming and outgoing will use same
generic label type, and the first label should be the incoming label,
and second label should be outgoing label.
The remote static PW element SHOULD be sent only along with local
static PW element, where the two PW elements belong to the same PW
Path. That means remote static PW element should not be sent
Jin & Chen Expires September 5, 2012 [Page 4]
Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012
independently.
The GAP Suppress message defined in [I-D.ietf-mpls-gach-adv] is only
applied for one application. We implement one particular static PW
element suppressing by defining a new TLV, called PW Suppress TLV, to
indicate suppressing special PW information transmission. Multiple
Generalized ID FEC elements could be included in this TLV. The
format would be as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|PW Suppress TLV| Reserved | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Generalized ID FEC +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multiple Generalized ID FEC! |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2
The type of PW suppress TLV is to be assigned by IANA. The format of
Generalized ID FEC is defined in [RFC4447]. The C-bit, PW type in
Generalized ID FEC should be zero.
A GAP message could contain both local&remote static PW element TLV
and PW Suppress TLV.
3.2. PE Procedure
3.2.1. PE message processing
The GAP message of static PW checking application should be sent at
least three times within lifetime.
For the static PW, the parameters of one pseudowire needed would
include: PW Path Identifier [RFC6370], PW type, Control Work, In&Out
PW Label, interface parameters and etc. When constructing "static PW
element" TLV, all the PW parameters should be carried.
When a PW is configured on the PE, and corresponding PSN Tunnel is
operational UP, PE SHOULD send its local PW configuration information
through GAP with local static PW element TLV. If PE has already
received remote PW configuration information belong to the same PW
Path through "local static PW element" TLV from remote PE, the GAP
Jin & Chen Expires September 5, 2012 [Page 5]
Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012
message SHOULD additionally include exactly the same received TLV in
"remote static PW element" TLV.
When the remote PE receives GAP message with static PW element TLV,
it SHOULD save the PW parameters in "local static PW element" TLV as
remote PW information for a period of "lifetime" which is specified
in the GAP message.
If the receiving GAP message also has "remote static PW element" TLV,
PE should check local PW parameters with that in "remote static PW
element" TLV. If the same, PE should send GAP message with PW
suppress TLV contained the specified PW information to peer PE. If
not, PE send GAP message with local PW configuration information
carried in "local static PW element" TLV, and the received remote PW
configuration information carried in "remote static PW element" TLV.
Whenever PE receives the GAP message with PW suppress TLV, it SHOULD
stop sending GAP message with specified PW information. Whenever the
PE updates locally PW configuration information, PE could send GAP
message with static PW element to update information in remote PE.
3.2.2. PW Configuration Check Process
The PE would associate a PW with Generalized PWid FEC of:
AGI = AGI
SAII = A1-{Global_ID::Node_ID::AC_ID}
TAII = Z9-{Global_ID::Node_ID::AC_ID}
and a PW with Generalized PWid FEC of:
AGI = AGI
SAII = Z9-{Global_ID::Node_ID::AC_ID}
TAII = A1-{Global_ID::Node_ID::AC_ID}
as one PW Path. When the PE has both local and remote PW parameters
for one PW, it should do parameter checking as follows:
1. Check control word, if both sides have same capability. If not,
an error would report.
2. Check PW type, if both sides have the same. If not, an error
would report.
3. Check and negotiate interface parameters as defined in [RFC4447].
4. Check In&Out PW label, if local in_label equals remote out_label,
and local out_label equals remote in_label. If not, an error would
report.
The mechanism described in this draft could also be used as label
advertisement, so as to avoid out_label negotiation manually between
two PE, and to avoid mis-configuration. Then the static PW is
allowed to configure only in_label instead of both in&out label.
Then if the remote PE does not send the out_label, PE will not check
local in_label and remote out_label. If PE does not have local
Jin & Chen Expires September 5, 2012 [Page 6]
Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012
out_label, it should use remote in_label as local out_label.
4. Security Considerations
No new security threat is introduced by the mechanism in this draft.
5. IANA Considerations
IANA is requested to allocate a new Application ID in the "G-Ach
Advertisement Protocol Applications and Data Types" registry.
A new TLV Object "Local Static PW Element" type is requested to be
allocated, suggested value would be 1.
A new TLV Object "Remote Static PW Element" type is requested to be
allocated, suggested value would be 2.
A new TLV Object "PW Suppress TLV" type is requested to be allocated,
suggested value would be 3.
6. Acknowledgements
The authors would like to thank Stewart Bryant for the his review and
contributions.
7. References
7.1. Normative references
[I-D.ietf-mpls-gach-adv]
Frost, D., Bocci, M., and S. Bryant, "MPLS Generic
Associated Channel (G-ACh) Advertisement Protocol",
draft-ietf-mpls-gach-adv-00 (work in progress),
January 2012.
7.2. Informative References
[RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G.
Heron, "Pseudowire Setup and Maintenance Using the Label
Distribution Protocol (LDP)", RFC 4447, April 2006.
[RFC5003] Metz, C., Martini, L., Balus, F., and J. Sugimoto,
"Attachment Individual Identifier (AII) Types for
Aggregation", RFC 5003, September 2007.
Jin & Chen Expires September 5, 2012 [Page 7]
Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012
[RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP
Specification", RFC 5036, October 2007.
[RFC6370] Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
Profile (MPLS-TP) Identifiers", RFC 6370, September 2011.
Authors' Addresses
Lizhong Jin
ZTE Corporation
889, Bibo Road
Shanghai, 201203, China
Email: lizhong.jin@zte.com.cn
Ran Chen
ZTE Corporation
No.19 East Huayuan Road
Beijing, 100191, China
Email: chen.ran@zte.com.cn
Jin & Chen Expires September 5, 2012 [Page 8]
