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RSVP-TE Signaling Extension for Links with Variable Discrete Bandwidth
draft-ietf-ccamp-rsvp-te-bandwidth-availability-02

The information below is for an old version of the document.
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This is an older version of an Internet-Draft that was ultimately published as RFC 8625.
Authors Hao Long , Min Ye , Greg Mirsky , Alessandro D'Alessandro , Himanshu C. Shah
Last updated 2015-07-05
Replaces draft-long-ccamp-rsvp-te-bandwidth-availability
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draft-ietf-ccamp-rsvp-te-bandwidth-availability-02
Network Working Group                                    H. Long, M. Ye 
Internet Draft                             Huawei Technologies Co., Ltd         
Intended status: Standards Track                              G. Mirsky  
                                                               Ericsson 
                                                         A.D'Alessandro 
                                                   Telecom Italia S.p.A 
                                                                H. Shah 
                                                                  Ciena                     
Expires: January 2016                                      July 2, 2015                               
 
                                      
        RSVP-TE Signaling Extension for Links with Variable Discrete 
                                Bandwidth 
           draft-ietf-ccamp-rsvp-te-bandwidth-availability-02.txt 

Abstract 

   A Packet switching network MAY contain links with variable bandwidth, 
   e.g., copper, radio, etc. The bandwidth of such links is sensitive 
   to external environment. Availability is typically used for 
   describing the link during network planning. This document 
   introduces an Extended Ethernet Bandwidth Profile TLV and an 
   OPTIONAL Availability sub-TLV in RSVP-TE signaling. This extension 
   can be used to set up a label switching path (LSP) in a Packet 
   Switched Network (PSN) that contains links with discretely variable 
   bandwidth. 

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), its areas, and its working groups.  Note that 
   other groups may also distribute working documents as Internet-
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   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." 

   The list of current Internet-Drafts can be accessed at 
   http://www.ietf.org/ietf/1id-abstracts.txt 

 
 
 
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   The list of Internet-Draft Shadow Directories can be accessed at 
   http://www.ietf.org/shadow.html 

   This Internet-Draft will expire on January 6, 2016. 

Copyright Notice 

   Copyright (c) 2015 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. 

Table of Contents 

   1. Introduction ................................................ 3 
   2. Overview .................................................... 4 
   3. Extension to RSVP-TE Signaling............................... 4 
         3.1.1. Extended Ethernet Bandwidth Profile TLV............ 5 
         3.1.2. Availability sub-TLV............................... 6 
      3.2. FLOWSPEC Object......................................... 6 
      3.3. Signaling Process....................................... 6 
   4. Security Considerations...................................... 7 
   5. IANA Considerations ......................................... 7 
      5.1  Ethernet Sender TSpec TLVs ............................. 7 
      5.2  Extended Ethernet Bandwidth Profile TLV ................ 8 
   6. References .................................................. 8 
      6.1. Normative References.................................... 8 
      6.2. Informative Reference .................................. 9 
   7. Appendix: Bandwidth Availability Example..................... 9 
   8. Acknowledgments ............................................ 11 
 
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 [RFC2119]. 

   The following acronyms are used in this draft: 

 
 
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   RSVP-TE  Resource Reservation Protocol-Traffic Engineering 

   LSP      Label Switched Path 

   PSN      Packet Switched Network 

   SNR      Signal-to-noise Ratio 

   TLV      Type Length Value 

   PE       Provider Edge 

   LSA      Link State Advertisement 

1. Introduction 

   The RSVP-TE specification [RFC3209] and GMPLS extensions [RFC3473] 
   specify the signaling message including the bandwidth request for 
   setting up a label switching path in a PSN network. 

   Some data communication technologies allow seamless change of 
   maximum physical bandwidth through a set of known discrete values. 
   The parameter availability [G.827, F.1703, P.530] is often used to 
   describe the link capacity during network planning. The availability 
   is a time scale that the requested bandwidth is ensured. A more 
   detailed example on the bandwidth availability can be found in 
   Appendix A. Assigning different availability classes to different 
   types of service over such kind of links provides more efficient 
   planning of link capacity. To set up an LSP across these links, 
   availability information is required for the nodes to verify 
   bandwidth satisfaction and make bandwidth reservation. The 
   availability information SHOULD be inherited from the availability 
   requirements of the services expected to be carried on the LSP. For 
   example, voice service usually needs ''five nines'' availability, 
   while non-real time services MAY adequately perform at four or three 
   nines availability. Since different service types MAY need different 
   availabilities guarantees, multiple <availability, bandwidth> pairs 
   MAY be required when signaling.  

   If the availability requirement is not specified in the signaling 
   message, the bandwidth will be reserved as the highest availability. 
   For example, the bandwidth with 99.999% availability of a link is 
   100 Mbps; the bandwidth with 99.99% availability is 200 Mbps. When a 
   video application requests for 120 Mbps without availability 
   requirement, the system will consider the request as 120 Mbps with 
   99.999% availability, while the available bandwidth with 99.999% 
   availability is only 100 Mbps, therefore the LSP path cannot be set 
 
 
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   up. But in fact, video application doesn't need 99.999% availability; 
   99.99% availability is enough. In this case, the LSP could be set up 
   if availability is specified in the signaling message.    

   To fulfill LSP setup by signaling in these scenarios, this document 
   specifies an Extended Ethernet Bandwidth Profile and an Availability 
   sub-TLV. The Availability sub-TLV can be applicable to any kind of 
   physical links with variable discrete bandwidth, such as microwave 
   or DSL. Multiple Extended Ethernet Bandwidth Profiles with different 
   availability can be carried in the Ethernet SENDER_TSPEC object. 

2. Overview 

   A PSN tunnel MAY span one or more links in a network. To setup a 
   label switching path (LSP), a PE node MAY collect link information 
   which is spread in routing message, e.g., OSPF TE LSA message, by 
   network nodes to get to know about the network topology, and 
   calculate out an LSP route based on the network topology, and send 
   the calculated LSP route to signaling to initiate a PATH/RESV 
   message for setting up the LSP. 

   In case that there is(are) link(s) with variable discrete bandwidth 
   in a network, a <bandwidth, availability> requirement list SHOULD be 
   specified for an LSP. Each <bandwidth, availability> pair in the 
   list means that listed bandwidth with specified availability is 
   required. The list could be inherited from the results of service 
   planning for the LSP.  

   A node which has link(s) with variable discrete bandwidth attached 
   SHOULD contain a <bandwidth, availability> information list in its 
   OSPF TE LSA messages. The list provides the information that how 
   much bandwidth a link can support for a specified availability. This 
   information is used for path calculation by the PE node(s). The 
   routing extension for availability can be found in [ARTE]. 

   When a PE node initiates a PATH/RESV signaling to set up an LSP, the 
   PATH message SHOULD carry the <bandwidth, availability> requirement 
   list as bandwidth request.  Intermediate node(s) will allocate the 
   bandwidth resource for each availability requirement from the 
   remaining bandwidth with corresponding availability. An error 
   message MAY be returned if any <bandwidth, availability> request 
   cannot be satisfied. 

3. Extension to RSVP-TE Signaling 

   The initial idea is to define an Availability sub-TLV under Ethernet 
   Bandwidth Profile TLV [RFC6003]. However the Ethernet Bandwidth 
 
 
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   Profile TLV doesn't have the ability to carry a sub-TLV according to 
   RFC6003. Therefore, an Extend Ethernet Bandwidth Profile TLV is 
   defined in this document to avoid the backward compatibility issue. 
   The Extended Ethernet Bandwidth Profile TLV includes Ethernet BW TLV 
   and has variable length. It MAY include Availability sub-TLV which 
   is also defined in this document.  

3.1.1. Extended Ethernet Bandwidth Profile TLV 

   The Extended Ethernet Bandwidth Profile TLV is included in the 
   Ethernet SENDER_TSPEC, and MAY be included for more than one time. 
   The Extended Ethernet Bandwidth Profile TLV has the following format. 

   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               | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |Pro|A|         |     Index     |          Reserved             | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |                              CIR                              |  
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |                              CBS                              | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |                              EIR                              | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |                              EBS                              | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |                       sub-TLV(OPTIONAL)                       | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
 
  Figure 1: A new ''AF'' filed in Extended Ethernet Bandwidth Profile TLV 

   The difference between the Extended Ethernet Bandwidth Profile TLV 
   and Ethernet Bandwidth Profile TLV is that a new AF field to 
   indicate the sub-TLV is defined in the Extended Ethernet Bandwidth 
   Profile TLV. The rest definitions are the same. 

   A new filed is defined in this document: 

     AF filed (bit 2): Availability Field (AF) 

   If the AF filed is set to 1, Availability sub-TLV MUST be included 
   in the Extended Ethernet Bandwidth Profile TLV. If the AF field is 
   set to value 0, then an Availability sub-TLV SHOULD NOT be included. 

 
 
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3.1.2. Availability sub-TLV 

   The Availability sub-TLV has the following format: 

       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          | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |                          Availability                         | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

                        Figure 2: Availability sub-TLV 

      Type (2 octets): TBD 

      Length (2 octets): 4 

      Availability (4 octets): a 32-bit floating number describes the 
      decimal value of availability requirement for this bandwidth 
      request. The value MUST be less than 1. 

   As the Extended Ethernet Bandwidth Profile TLV can be carried for 
   one or more times in the Ethernet SENDER_TSPEC object, the 
   Availability sub-TLV can also be present for one or more times. 

3.2. FLOWSPEC Object 

   The FLOWSPEC object (Class-Num = 9, Class-Type = TBD) has the same 
   format as the Ethernet SENDER_TSPEC object. 

3.3. Signaling Process 

   The source node initiates PATH messages including one or more 
   Extended Bandwidth Profile TLVs with different availability values 
   in the SENDER_TSPEC object. Each Extended Bandwidth Profile TLV 
   specifies the portion of the bandwidth request with referred 
   availability requirement. 

   The intermediate and destination nodes check whether they can 
   satisfy the bandwidth requirements by comparing each bandwidth 
   requirement inside the SENDER_TSPEC objects with the remaining link 
   sub-bandwidth resource with respective availability guarantee when 
   received the PATH message.  

 
 
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     o   If all <bandwidth, availability> requirements can be 
        satisfied, it SHOULD reserve the bandwidth resource from each 
        remaining sub-bandwidth portion to set up this LSP. Optionally, 
        the higher availability bandwidth can be allocated to lower 
        availability request when the lower availability bandwidth 
        cannot satisfy the request. 

     o   If at least one <bandwidth, availability> requirement cannot 
        be satisfied, it SHOULD generate PathErr message with the error 
        code "Admission Control Error" and the error value "Requested 
        Bandwidth Unavailable" (see [RFC2205]). 

   If two LSPs request for the bandwidth with the same availability 
   requirement, a way to resolve the contention is comparing the node 
   ID, the node with the higher node ID will win the contention. More 
   details can be found in [RFC3473]. 

   If a node does not support the Extended Bandwidth Profile TLV and 
   Availability sub-TLV, it SHOULD generate PathErr message with the 
   error code "Extended Class-Type Error" and the error value "Class-
   Type mismatch" (see [RFC2205]).  

4. Security Considerations 

   This document does not introduce new security considerations to the    
   existing RSVP-TE signaling protocol. 

5. IANA Considerations 

   IANA maintains registries and sub-registries for RSVP-TE used by 
   GMPLS. IANA is requested to make allocations from these registries 
   as set out in the following sections.  

5.1 Ethernet Sender TSpec TLVs  

   IANA maintains a registry of GMPLS parameters called ''Generalized 
   Multi-Protocol Label Switching (GMPLS) Signaling Parameters''. 

   IANA has created a new sub-registry called ''Ethernet Sender TSpec 
   TLVs / Ethernet Flowspec TLVs'' to contain the TLV type values for 
   TLVs carried in the Ethernet SENDER_TSPEC object. A new value is as 
   follow: 

    

   Type       Description                            Reference 

 
 
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   -----      -----------------------------------    --------- 

   TBD        Extended Ethernet Bandwidth Profile    [This ID]          

5.2 Extended Ethernet Bandwidth Profile TLV 

   IANA has created a new sub-registry called ''Extended Ethernet 
   Bandwidth Profiles'' to contain bit flags carried in the Extended 
   Ethernet Bandwidth Profile TLV of the Ethernet SENDER_TSPEC object. 

   Bits are to be allocated by Standards Action. Bits are numbered from 
   bit 0 as the low order bit. A new bit field is as follow: 

   Bit     Hex               Description              Reference 

   ---     ----              ------------------       ----------- 

   0       0x01              Coupling Flag (CF)        [RFC6003] 

   1       0x02              Color Mode (CM)           [RFC6003] 

   2       0x04              Availability Field (AF)   [This ID] 

   Sub-TLV types for Extended Ethernet Bandwidth Profiles are to be 
   allocated by Standards Action. Initial values are as follows: 

   Type    Length          Format                        Description 

   ---     ----            ------------------            ----------- 

   0        -              Reserved                      Reserved value 

   0x01     4              see Section 3.1.2 of this ID  Availability           

6. References 

6.1. Normative References 

   [RFC2210] Wroclawski, J., ''The Use of RSVP with IETF Integrated 
             Services'', RFC 2210, 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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   [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching            
             (GMPLS) Signaling Resource ReserVation Protocol-Traffic            
             Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. 

   [RFC6003] Papadimitriou, D. ''Ethernet Traffic Parameters'', RFC 6003, 
             October 2010. 

   [G.827]  ITU-T Recommendation, ''Availability performance parameters 
             and objectives for end-to-end international constant bit-
             rate digital paths'', September, 2003. 

   [F.1703]  ITU-R Recommendation, ''Availability objectives for real 
             digital fixed wireless links used in 27 500 km 
             hypothetical reference paths and connections'', January, 
             2005. 

   [P.530]   ITU-R Recommendation,'' Propagation data and prediction 
             methods required for the design of terrestrial line-of-
             sight systems'', February, 2012 

   [EN 302 217] ETSI standard, ''Fixed Radio Systems; Characteristics 
             and requirements for point-to-point equipment and 
             antennas'', April, 2009 

   [ARTE]    H., Long, M., Ye, Mirsky, G., Alessandro, A., Shah, H., 
             ''OSPF Routing Extension for Links with Variable Discrete 
             Bandwidth'', Work in Progress, February, 2014 

6.2. Informative References 

   [MCOS]    Minei, I., Gan, D., Kompella, K., and X. Li, "Extensions           
             for Differentiated Services-aware Traffic Engineered              
             LSPs", Work in Progress, June 2006. 

7. Appendix: Bandwidth Availability Example 

   In mobile backhaul network, microwave links are very popular for 
   providing connection of last hops. In case of heavy rain, to 
   maintain the link connectivity, the microwave link MAY lower the 
   modulation level since demodulating the lower modulation level needs 
   a lower Signal-to-Noise Ratio (SNR). This is called adaptive 
   modulation technology [EN 302 217]. However, a lower modulation 
   level also means lower link bandwidth. When link bandwidth is 
   reduced because of modulation down-shifting, high-priority traffic 
   can be maintained, while lower-priority traffic is dropped. 
   Similarly, the copper links MAY change their link bandwidth due to 
   external interference. 
 
 
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   Presuming that a link has three discrete bandwidth levels:  

   The link bandwidth under modulation level 1, e.g., QPSK, is 100 Mbps; 

   The link bandwidth under modulation level 2, e.g., 16QAM, is 200 
   Mbps; 

   The link bandwidth under modulation level 3, e.g., 256QAM, is 400 
   Mbps. 

   In sunny day, the modulation level 3 can be used to achieve 400 Mbps 
   link bandwidth. 

   A light rain with X mm/h rate triggers the system to change the 
   modulation level from level 3 to level 2, with bandwidth changing 
   from 400 Mbps to 200 Mbps. The probability of X mm/h rain in the 
   local area is 52 minutes in a year. Then the dropped 200 Mbps 
   bandwidth has 99.99% availability. 

   A heavy rain with Y(Y>X) mm/h rate triggers the system to change the 
   modulation level from level 2 to level 1, with bandwidth changing 
   from 200 Mbps to 100 Mbps. The probability of Y mm/h rain in the 
   local area is 26 minutes in a year. Then the dropped 100 Mbps 
   bandwidth has 99.995% availability. 

   For the 100M bandwidth of the modulation level 1, only the extreme 
   weather condition can cause the whole system unavailable, which only 
   happens for 5 minutes in a year. So the 100 Mbps bandwidth of the 
   modulation level 1 owns the availability of 99.999%. 

   In a word, the maximum bandwidth is 400 Mbps. According to the 
   weather condition, the sub-bandwidth and its availability are shown 
   as follows: 

   Sub-bandwidth(Mbps)    Availability                       

   ------------------     ------------          

   200                    99.99%                 

   100                    99.995%                

   100                    99.999%                

 
 
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8. Acknowledgments 

   The authors would like to thank Khuzema Pithewan, Lou Berger, Yuji 
   Tochio, Dieter Beller, and Autumn Liu for their comments on the 
   document. 

    

    

    

   Authors' Addresses 

 
 
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   Hao Long 
   Huawei Technologies Co., Ltd. 
   No.1899, Xiyuan Avenue, Hi-tech Western District 
   Chengdu 611731, P.R.China 
    
   Phone: +86-18615778750 
   Email: longhao@huawei.com 
    
    
   Min Ye (editor) 
   Huawei Technologies Co., Ltd. 
   No.1899, Xiyuan Avenue, Hi-tech Western District 
   Chengdu 611731, P.R.China 
 
   Email: amy.yemin@huawei.com 
    
   Greg Mirsky (editor) 
   Ericsson 
    
   Email: gregory.mirsky@ericsson.com 
    
   Alessandro D'Alessandro 
   Telecom Italia S.p.A 
    
   Email: alessandro.dalessandro@telecomitalia.it 
    
    
   Himanshu Shah 
   Ciena Corp. 
   3939 North First Street 
   San Jose, CA 95134 
   US 
    
   Email: hshah@ciena.com 
    

 

 
 
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