OSPF Routing Extension for links with variable discrete bandwidth
draft-long-ccamp-ospf-availability-extension-00

Network Working Group                                           H. Long 
Internet Draft                                                     M.Ye 
Intended status: Standards Track           Huawei Technologies Co., Ltd 
                                                              G. Mirsky 
                                                               Ericsson 
                                                           A Alessandro 
                                                   Telecom Italia S.p.A 
Expires: January 2014                                      July 3, 2013  
 
                                      
     OSPF Routing Extension for links with variable discrete bandwidth 
            draft-long-ccamp-ospf-availability-extension-00.txt 

Abstract 

   Packet switching network may contain links with variable discrete 
   bandwidth, e.g., copper, radio, etc. The bandwidth of such link may 
   change discretely in reaction to changing external environment. 
   Availability is typically used for describing such links during 
   network planning. This document describes an extension for OSPF 
   routing for route computation in a Packet Switched Network (PSN) 
   which contains link with variable discrete bandwidth by introducing 
   an optional availability sub-TLV. 

Status of this Memo 

   This Internet-Draft is submitted in full conformance with the 
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   This Internet-Draft will expire on January 7, 2009. 

 
 
 
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Copyright Notice 

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   document authors. All rights reserved. 

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Table of Contents 

   1. Introduction ................................................ 3 
   2. Overview .................................................... 3 
   3. Extension to OSPF Routing Protocol .......................... 4 
      3.1. Interface Switching Capacity Descriptor................. 4
      3.2. ISCD Availability sub-TLV............................... 4 
      3.3. Signaling Process....................................... 5 
   4. Security Considerations...................................... 5 
   5. IANA Considerations ......................................... 5 
   6. References .................................................. 5 
      6.1. Normative References.................................... 5 
      6.2. Informative References.................................. 6 
   7. Acknowledgments ............................................. 6 
 
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: 

   OSPF    Open Shortest Path First 

   PSN     Packet Switched Network 

   SNR     Signal-to-noise Ratio 

   LSP     Label Switched Path 

   ISCD    Interface Switching Capacity Descriptor 
 
 
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   PE      Provider Edge 

   LSA     Link State Advertisement 

1. Introduction 

   There are some data communication technologies that allow seamless 
   change of maximum physical bandwidth. For 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 will lower the modulation level 
   since demodulating lower modulation level need lower signal-to-noise 
   ratio (SNR). This is called adaptive modulation technology [EN 302 
   217]. However, lower modulation level also means lower link 
   bandwidth. When link bandwidth reduces by modulation down-shifting, 
   high priority traffic can be maintained, while lower priority 
   traffic is dropped. Similarly the cooper links may change their 
   effective link bandwidth due to external interference.  

   The parameter, availability [G.827, F.1703, P.530], is often used to 
   describe the link capacity during network planning. 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, voice service usually needs "five 
   nines" availability, while non-real time data packets may needs four 
   or three nines availability.  

   For the route computation, the availability information should be 
   provided along with bandwidth resource information. In this document, 
   an extension on Interface Switching Capacity Descriptor (ISCD) 
   [RFC4202] for availability information support in routing signaling. 
   The extension reuses the reserved field in the ISCD and also 
   introduces an optional availability sub-TLV.  

2. Overview 

   A node which has link(s) with variable 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).  

 
 
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   To setup a label switching path (LSP), a PE node may collect link 
   information which is spread in OSPF TE LSA message by network nodes 
   to get know about the network topology, and calculate out a 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. 

3. Extension to OSPF Routing Protocol 

3.1. Interface Switching Capacity Descriptor 

   The Interface Switching Capacity Descriptor (ISCD) sub-TLV [RFC 4203] 
   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               | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      | Switching Cap |   Encoding    |      AI       |   Reserved    | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      ~                  Switching Capacity Information               ~ 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

      Type: TBD, 16 bits; 

      Length: 16 bits; 

      AI: ISCD Availability sub-TLV index, 8 bits 

         This field is the index of availability sub-TLV for this ISCD 
         sub-TLV.  

3.2. ISCD 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          | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |      Index    |                     Reserved                  | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |                   Availability Information                    | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

 
 
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      Type: TBD, 16 bits; 

      Length: 16 bits; 

      Index: 8 bits 

           This field is the index of this availability sub-TLV, 
           referred by the AI field of the ISCD sub-TLV. 

       Availability Information: 32 bits 

           This field is a 32-bit IEEE floating point number which 
           describes the availability guarantee of the switching 
           capacity in the ISCD object which has the AI value equal to 
           Index of this sub-TLV. The value must be less than 1. 

3.3. Signaling Process 

   A node which has link(s) with variable bandwidth attached should 
   contain one or more ISCD Availability sub-TLVs in its OSPF TE LSA 
   messages. Each ISCD Availability sub-TLV 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).  

4. Security Considerations 

   This document does not introduce new security considerations to the    
   existing OSPF protocol. 

5. IANA Considerations 

   TBD 

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. 

   [RFC4202] Kompella, K. and Rekhter, Y. (Editors), "Routing 
             Extensions in Support of Generalized Multi-Protocol Label 
             Switching (GMPLS)", RFC 4202, October 2005. 

   [RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions 
             in Support of Generalized Multi-Protocol Label Switching 
             (GMPLS)", RFC 4203, October 2005. 

   [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 

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. Acknowledgments 

    

    

   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 
   Huawei Technologies Co., Ltd. 
   No.1899, Xiyuan Avenue, Hi-tech Western District 
   Chengdu 611731, P.R.China 
 
   Email: amy.yemin@huawei.com 
    
   Greg Mirsky 
   Ericsson 
    
   Email: gregory.mirsky@ericsson.com 
    
   Alessandro D'Alessandro 
   Telecom Italia S.p.A 
    
   Email: alessandro.dalessandro@telecomitalia.it 

 
 
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