Internet DRAFT - draft-zhang-ccamp-rsvpte-ber-measure
draft-zhang-ccamp-rsvpte-ber-measure
Network Working Group Z. Li
Internet-Draft L. Zhang
Intended status: Standards Track Huawei Technologies
Expires: January 4, 2015 G. Yang
China Telecom
July 3, 2014
RSVP-TE Extensions for Bit Error Rate (BER) Measurement
draft-zhang-ccamp-rsvpte-ber-measure-02
Abstract
In the mobile backhaul network, the mobile service is sensitive to
Bit Error Rate (BER). When the BER value of the service exceeds the
threshold, the cell site equipments will stop working and the mobile
terminal users cannot obtain voice and data services anymore. Now
the mobile backhaul tends to be IP/MPLS network and MPLS TE LSP is
used to bear the mobile service which may be encapsulated in PW or
L3VPN end to end. Then the ingress Label Switched Router (LSR) of
the MPLS TE LSP needs to get information on BER along the path of the
LSP. This document proposes new extensions of RSVP-TE to advertise
the BER measurement requirement of the specific LSP to all of the
transit LSRs and the egress LSR, and to report the BER measurement
result from any transit or egress LSR towards the ingress LSR.
Requirements Language
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].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 4, 2015.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. BER_REQUEST TLV . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Format of BER_REQUEST . . . . . . . . . . . . . . . . . . 3
3.2. Procedures for BER_REQUEST TLV . . . . . . . . . . . . . 5
4. BER Measurement Result Report . . . . . . . . . . . . . . . . 5
4.1. Error Code for BER measurement report . . . . . . . . . . 5
4.2. Procedures for BER Error Code . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Bit Error Rate (BER) is a significant parameter for the mobile
service, which can cause the cell site equipment to stop working when
its value exceeds the threshold that the mobile service can tolerate.
In IP/MPLS based mobile backhaul network, PW and L3VPN are adopted to
bear the mobile service, and MPLS TE LSP is adopted as the transport
tunnel for which Hot-standby (MPLS TE HSB) or fast reroute (MPLS TE
FRR) technologies is used to meet the SLA(Service Level Agreement).
There are different kinds of failure detection methods, such as
BFD[RFC5884] or MPLS OAM[RFC4378], to trigger fast traffic switch
when failure happens. But as to BER, even if the BER value exceeds
the threshold, the detection mechanisms may be not able to detect the
failure to trigger traffic switch to the backup path. In order to
solve the issue, RSVP-TE extensions can be introduced to notify the
ingress LSR of the BER measurement result when a specific LSR along
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the LSP detects that the BER value exceeds the threshold or restores
to the normal value below the threshold. When the ingress LSP
receives the BER measurement result, it can switch the traffic
between the primary path and the backup path which is policy specific
and out of scope of the document.
This document defines new extensions of RSVP-TE for BER measurement:
One extension is to advertise the BER measurement requirement to all
of the transit LSRs and the egress LSR, then these LSRs along the
path will start BER measurement for the LSP. The other extension is
to report the BER measurement result from any transit LSR or the
egress LSR towards the ingress LSR.
2. Terminology
BER: Bit Error Rate
RAN: Radio Access Network
LSR: Label Switch Router
LSP: Label Switch Path
3. BER_REQUEST TLV
3.1. Format of BER_REQUEST
Path Message of RSVP-TE is used to signal the BER measurement
requirement of the LSP, and the LSP_ATTRIBUTES object will be
included in the Path Message. The LSP_ATTRIBUTES object which is
defined in [RFC5420] is used to signal attributes required in support
of an LSP, or to indicate the nature or use of an LSP. The
LSP_ATTRIBUTES object format is as below (refer to[RFC5420]):
LSP_ATTRIBUTES class = 197, C-Type = 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Attributes TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: LSP_ATTRIBUTES object
The LSP_ATTRIBUTES object class is 197 of the form 11bbbbbb. This
C-Num value (see [RFC2205], Section 3.10) ensures that LSRs that do
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not recognize the object pass it on transparently. One C-Type is
defined, C-Type = 1 for LSP Attributes.
The Attributes TLVs are encoded as 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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Value //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Attributes TLVs format
Here we define the BER_REQUEST TLV which is a new type of Attribute
TLV to indicate the BER measurement requirement of the LSP. The
format of BER_REQUEST TLV is as below:
LSP_ATTRIBUTES Class=197, C-Type=1
Type=TBD, BER_REQ TLV
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 = BER_REQ TLV(TBD) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BER threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3:BER_REQUEST TLV
Type
The identifier of the BER_REQUEST TLV which should be allocated by
IANA.
Length
Indicates the total length of the TLV in two octets.
Value
The BER threshold for the service. It is a 32-bit IEEE floating
point number. The format of IEEE floating-point numbers is further
summarized in [RFC1832].
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3.2. Procedures for BER_REQUEST TLV
BER_REQUEST TLV is one type of attribute TLVs of the LSP_ATTRIBUTE
object. It is optional and MAY be placed in Path messages to
advertise the BER measurement requirement of the LSP. The process of
the LSP_ATTRIBUTE object can refer to section 4.2 in [RFC5420].
When a RSVP-TE LSP requires the BER measurement of the path, the
ingress LSR MUST send a Path Message with BER_REQUEST TLV in which
the BER threshold value is set according to the service requirement.
When an LSR receives a Path Message with the BER_REQUEST TLV, the LSR
SHOULD start the BER measurement for the LSP. The LSR MUST pass the
Path Message with BER_REQUEST TLV unchanged to the next LSR. If the
measured BER value exceeds the BER threshold value set in the
BER_REQUEST TLV, the LSR MUST report the bit error result towards the
ingress LSR of the LSP.
If an LSR cannot support the BER_REQUEST TLV, the LSR SHOULD ignore
this TLV and pass the Path Message with BER_REQUEST TLV unchanged to
the next LSR.
For an LSR which has started the BER measurement on receiving the
Path Message with the BER_REQUEST UEST TLV, if the LSR receives the
updated Path Message without BER_REQUEST TLV, it MUST stop the BER
measurement for this LSP and pass the Path Message unchanged to the
next LSR.
4. BER Measurement Result Report
For an LSR that starts the BER measurement, When the BER measurement
value exceeds the threshold for the service, the LSR MUST report the
indication of bit error towards the ingress LSR of the LSP. If the
LSR has already reported the indication of bit error, it MUST report
the elimination of bit error towards the ingress LSR when it measures
that the BER is blow the specified threshold. A new type of Error
Code and its Error Value of the ERROR_SPEC object are defined to
report the BER measurement result within PathErr Message.
4.1. Error Code for BER measurement report
The ERROR_SPEC object is defined in [RFC2205] and [RFC3209]. The BER
Error Code and its Error Values are defined as below:
Error Code Error Value Description
-----------------------------------------------------------------
TBD 0 Bit Error Elimination
1 Bit Error Indication
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4.2. Procedures for BER Error Code
The BER measurement result is reported through a new Error Code and
the corresponding Error Value of the ERROR_SPEC object which is
placed in PathErr Message.
For a LSR which has started the BER measurement for the specific LSP,
if the BER measurement value exceeds the threshold of the service, a
PathErr Message MUST be sent towards the ingress LSR of this LSP.
The PathErr Message MUST include an ERROR_SPEC object with the BER
Error code and Error Value 1 for Bit Error Indication. When the BER
measurement value becomes less than the BER threshold value after
report the Bit Error Indication, the LSR MUST send a PathErr Message
including an ERROR_SPEC object with the BER Error Code and Error
Value 0 for Bit Error Elimination.
5. IANA Considerations
IANA should allocate the type value of the BER_REQUEST TLV and the
BER Error Code which are defined in this document.
6. Security Considerations
The extensions of RSVP TE for BER in this document do not introduce
any new security issues, and the reader is referred to the security
considerations expressed in [RFC2205], [RFC3209], and [RFC5420].
7. References
7.1. Normative References
[RFC1832] Srinivasan, R., "XDR: External Data Representation
Standard", RFC 1832, August 1995.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
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[RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and A.
Ayyangarps, "Encoding of Attributes for MPLS LSP
Establishment Using Resource Reservation Protocol Traffic
Engineering (RSVP-TE)", RFC 5420, February 2009.
7.2. Informative References
[RFC4378] Allan, D. and T. Nadeau, "A Framework for Multi-Protocol
Label Switching (MPLS) Operations and Management (OAM)",
RFC 4378, February 2006.
[RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"Bidirectional Forwarding Detection (BFD) for MPLS Label
Switched Paths (LSPs)", RFC 5884, June 2010.
Authors' Addresses
Zhenbin Li
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: lizhenbin@huawei.com
Li Zhang
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: monica.zhangli@huawei.com
Guangming Yang
China Telecom
No. 109, Zhongshan Road West, Tianhe District
Guangzhou 510630
China
Email: yanggm@gsta.com
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