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Versions: 00 01 02                                                      
Network Working Group                                           M. Zhang
Internet-Draft                                                   H. Ding
Intended status: Informational                                  YL. Zhao
Expires: April 21, 2011                                             BUPT
                                                               HY. Zhang
                                                                  YB. Xu
                                                                    CATR
                                                        October 18, 2010


Performance Metric of Convergence Time of Information Flooding in Multi-
                         Domain GMPLS Networks
                      draft-zhangm-ccamp-metric-00

Abstract

   To keep the information of topology and links resource synchronized
   at each control node, massive messages are necessary to be flooded in
   the control plane of General Multi-Protocol Label Switching (GMPLS)
   based multi-domain networks.  The convergence time of information
   flooding will have a significant impact on the performance of the
   networks.  So measuring and analyzing the convergence time of
   information flooding in multi-domains becomes very important.  A
   performance metric of convergence time of information flooding is
   proposed to characterize the ability of information synchronization
   in multi-domain networks.

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
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   This Internet-Draft will expire on April 21, 2011.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.



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   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
     1.1.  Motivations  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions Used in this Document  . . . . . . . . . . . . . .  4
   3.  Overview of the Performance metric . . . . . . . . . . . . . .  4
   4.  convergence time of information flooding in single domain  . .  4
     4.1.  Initial convergence time of information flooding . . . . .  4
       4.1.1.  Definition . . . . . . . . . . . . . . . . . . . . . .  4
       4.1.2.  Methodology  . . . . . . . . . . . . . . . . . . . . .  4
       4.1.3.  Sample . . . . . . . . . . . . . . . . . . . . . . . .  5
     4.2.  convergence time of information flooding with LSPs . . . .  6
       4.2.1.  Definition . . . . . . . . . . . . . . . . . . . . . .  6
       4.2.2.  Methodology  . . . . . . . . . . . . . . . . . . . . .  6
       4.2.3.  Sample . . . . . . . . . . . . . . . . . . . . . . . .  7
   5.  Convergence time of information flooding in multi-domain
       networks . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
     5.1.  Initial convergence time of information flooding . . . . .  8
       5.1.1.  Definition . . . . . . . . . . . . . . . . . . . . . .  8
       5.1.2.  Methodology  . . . . . . . . . . . . . . . . . . . . .  8
       5.1.3.  Sample . . . . . . . . . . . . . . . . . . . . . . . .  9
     5.2.  Convergence time of information flooding with LSPs . . . . 10
       5.2.1.  Definition . . . . . . . . . . . . . . . . . . . . . . 10
       5.2.2.  Methodology  . . . . . . . . . . . . . . . . . . . . . 11
       5.2.3.  Sample . . . . . . . . . . . . . . . . . . . . . . . . 12
   6.  Protocol Extension Requirements  . . . . . . . . . . . . . . . 14
     6.1.  OSPF-TE Extension Requirements . . . . . . . . . . . . . . 14
     6.2.  RSVP-TE Extension Requirements . . . . . . . . . . . . . . 14
   7.  Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 14
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 15
   9.  Acknowledgement  . . . . . . . . . . . . . . . . . . . . . . . 15
   10. Normative References . . . . . . . . . . . . . . . . . . . . . 15
   Appendix A.  author  . . . . . . . . . . . . . . . . . . . . . . . 15
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16






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1.  Introduction

   Generalized Multi-Protocol Label Switching (GMPLS) [RFC3945], which
   can handle multiple switching technologies: packet switching (PSC),
   Layer 2 switching (L2SC), Time-Division Multiplexing (TDM) Switching,
   wavelength switching (LSC) and fiber switching (FSC), is a key
   technology for transport and service network.  As the network varies
   from time to time, division of the network is a natural solution to
   cope with large scale network control and management.  In order to
   keep the information of topology and links resource synchronized,
   which is necessary during the process of path computation, massive
   messages are necessary to be flooded in the control plane of multi-
   domain networks.  So measuring and analyzing the convergence time of
   information flooding in multi-domain networks becomes very important.
   RFC 5814 has defined three metric to characterize the dynamic Label
   Switching Path (LSP) provisioning performance of signaling protocol.
   However, performance metric that concerns routing protocols,
   especially in multi-domain network are not specified in previous
   documents.

   In this document, we define a performance metric of convergence time
   of information flooding from the routing aspect to characterize the
   ability of information synchronization in multi-domain networks.  The
   metric can be used to measure convergence time of information
   flooding in single domain, multi-domains, initial and with LSPs.
   Methodologies and samples of the testing procedure for different
   scenarios are also included in the following sections.

1.1.  Motivations

   Convergence time of information flooding is useful for several
   reasons.

   o  When a large scale network is deployed, a series of tests are to
      be conducted to evaluate the network performance, such as adding
      or deleting the clients, establishing or tearing the connections,
      and so on.  The convergence time, which indicates the ability to
      synchronize the topology and link resource states, is also worth
      measuring and analyzing meantime, since it can further illustrate
      the reasonability of domain division.

   o  During the operation, nodes or links failures MAY cause congestion
      due to both resource unavailability and a large amount of
      information flooding.  Measuring and monitoring convergence time
      of information flooding is helpful for network failure detection.

   o  After network updating and large scale reconfiguration,
      convergence time of information flooding should be measured,



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      because it MAY reflect the reasonability of this updating by
      comparing the convergence time of information flooding with the
      LSP setup delay.


2.  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 [RFC2119].


3.  Overview of the Performance metric

   To evaluate the convergence ability of a GMPLS-based network from
   routing aspect, we define a performance metric of convergence time of
   information flooding.  The following sections specify the metric in
   different situations, initial or with LSPs, in single domain or
   multi-domains.  The initial convergence time of information flooding
   measures the time that one network spends from its power-on to its
   full operation.  The convergence time with LSPs measures the time
   needed to synchronize the information after several changes in link
   resource states.  The convergence time in single domain is intra-
   domain time whereas the convergence time in multi-domains comprises
   intra-domain time and inter-domain time and the two kinds of
   convergence time need to compute separately.

   The convergence time of information flooding is either a real number
   of milliseconds or undefined.  And in methodology "undefined"
   convergence time is defined.


4.  convergence time of information flooding in single domain

4.1.  Initial convergence time of information flooding

4.1.1.  Definition

   The initial convergence time of information flooding describes a
   period of time, which starts at the moment when the first bit of the
   first Hello packet is sent and ends at the moment when all nodes
   database synchronized in this domain.

4.1.2.  Methodology

   Generally, the convergence time of initial information flooding in
   single domain proceeds as follows,




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   o  All control nodes in this domain switch on normally;

   o  Store a time structure, which records the first sending moment of
      Hello packets, in every control node.  And the starting point (T1)
      of the convergence time is the earliest sending moment among all
      control nodes in this domain;

   o  After the neighbor relationships are established, Database
      Description (DD) packets are sent and received to synchronize the
      information topology and links resource according to RFC 2328.
      Then all nodes in the domain are marked as full adjacency.  Store
      a time structure, which records the latest receiving moment of DD
      packets, in every node.  Choose the latest moment among all
      control nodes as end point (T2);

   o  Initial convergence time of information flooding in single domain
      can be computed by subtracting the starting point from end point
      (T2-T1).

4.1.3.  Sample


   . . . . . . . . . . . . . . . .
   . +-----+  +-----+  +-----+   .
   . |NODE1|--|NODE2|--|NODE3|   .
   . +-----+  +-----+  +-----+   .
   .    |    /                   .
   . +-----+/    +-----+         .
   . |NODE4|-----|NODE5|         .
   . +-----+     +-----+         .
   .                             .
   .                     domain  .
   . . . . . . . . . . . . . . . .

      Figure 1: Initial information synchronization in single domain

   Control nodes are represented by vertices and physical links are
   represented by dashed lines.  When all these control nodes switch on
   normally and their interfaces first become operational, Hello packets
   are flooded in this domain to establish neighbor relationships as
   described in Section 7, RFC1583.

   For a domain as shown in Figure 1, after the power-on, all five nodes
   begin to send and receive Hello packets.  In most occasions, these
   nodes receive the message in a very short interval which is normally
   a few microseconds.  So practically a structure of time is stored in
   every node to record the moment, which is the time when the node
   sends a Hello packet.  The starting point of the initial convergence



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   time of information flooding is the earliest sending moment of all
   the Hello packets.

   After the establishment of neighbor relationships, DD packets are
   sent and received to compare the nodes database so as to establish
   adjacency relationships.  And the receiving moments of DD packets
   SHOULD be stored in another time structure in every node.  Then
   choose the latest moment among all the receiving moments relating to
   DD packets as the end point of the convergence time of information
   flooding in this scenario.

   So the initial convergence time of information flooding in single
   domain can be computed by subtracting the starting point from the end
   point.

4.2.  convergence time of information flooding with LSPs

4.2.1.  Definition

   The convergence time of information flooding with LSPs describes a
   time period, that starts at the moment when the ingress node sends
   the first bit of a Link State Update (LSU) packet and ends at the
   moment when the last node in this domain receives the LSU packet.

   The undefined convergence time of information flooding with LSPs
   means ingress node fails to receive corresponding ResvConf message,
   which MAY indicates resource reservation failure or nodes breaking
   down along the LSP.

4.2.2.  Methodology

   Generally, the methodology proceeds as follows,

   o  All control nodes in this domain switch on normally;

   o  Initial information synchronization is complete, which means all
      node Link State Database (LSDBs) are up-to-date;

   o  Select an ingress node ID0 and an egress node ID1, and create a
      LSP path from ID0 to ID1.

   o  Wait until ID0 receives the corresponding ResvConf message and
      updates its LSDB and forms a LSU packet LSU0.  Store a timestamp
      (T1) at ID0 as soon as possible;

   o  Another timestamp (T2) SHOULD be stored when the last node within
      this domain receives LSU0 at the exact last node;




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   o  The convergence time of information flooding with LSPs in single
      domain can be computed by subtracting the two timestamps (T2-T1);

   o  If ID0 fails to receive the corresponding ResvConf message in a
      reasonable period of time, the convergence time is set to
      undefined.

4.2.3.  Sample


   . . . . . . . . . . . . . . . .
   . +-----+  +-----+  +-----+   .
   . |NODE1|==|NODE2|==|NODE3|   .
   . +-----+  +-----+  +-----+   .
   .    ||   /                   .
   . +-----+/    +-----+         .
   . |NODE4|=====|NODE5|         .
   . +-----+     +-----+         .
   .                             .
   .                     domain  .
   . . . . . . . . . . . . . . . .}

      Figure 2: Convergence time of information flooding with LSPs in
                               single domain

   Control nodes are represented by vertices and physical links are
   represented by dashed lines, LSPs are represented by equal signs.
   For a single domain as shown in Figure 2, NODE1->NODE2->NODE3
   constitute LSP1 which already exists, and NODE1->NODE4->NODE5
   constitute LSP2 which need to be measured.

   When NODE1, the ingress node of LSP2, receives a ResvConf message
   correspondingly with LSP2, it forms an LSU packet including changed
   LSAs and floods it within the domain.  NODE2 and NODE4 receive the
   LSU and then NODE3 and NODE5 receive the message.  A time structure
   is stored in every control node to record the earliest sending moment
   and latest receiving moment of LSU packets.  The ingress node NODE1's
   sending moment can be the starting point and choose the latest moment
   among NODE2's, NODE3's, NODE4's, NODE5's receiving moments as the end
   point of the convergence time.

   So the convergence time of information flooding with LSPs in single
   domain as depicted in Figure 2 can be computed by subtracting the
   starting point from the end point.







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5.  Convergence time of information flooding in multi-domain networks

5.1.  Initial convergence time of information flooding

5.1.1.  Definition

   Initial convergence time of information flooding in multi-domain
   network defines a time period, which starts at the moment when the
   first Hello packet is sent and ends at the moment when all nodes
   database synchronized in the network.

5.1.2.  Methodology

   Generally, convergence time of information flooding in multi-domain
   network proceeds as follows,

   o  All control nodes in multi-domains switch on normally;

   o  Store a time structure, which records the first sending moment of
      Hello packets in every control node.  And the starting point (T1)
      of the convergence time is the earliest sending moment among all
      control nodes in the multi-domain network;

   o  After the neighbor relationships are established, Database
      Description (DD) packets are sent and received to synchronize the
      information topology and links resource according to RFC 2328.
      Then all nodes in the domain are marked as full adjacency.  Store
      a time structure, which records latest receiving moment of DD
      packets, in every node.  Choose the latest moment among all these
      structures as another timestamp (T2);

   o  Initial convergence time of information flooding in the multi-
      domain network can be computed by subtracting the two timestamps
      (T2-T1).

















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5.1.3.  Sample


   . . . . . . . . . . . . . . . .
   . +-----+  +-----+  +-----+   .
   . |NODE1|--|NODE2|--|NODE3|   .
   . +-----+  +-----+  +-----+   .
   .    |    /            |      .
   . +-----+/    +-----+  |      .
   . |NODE4|-----|NODE5|  |      .
   . +-----+     +-----+  |      .
   .                      |      .
   . Domain1              |      .
   . . . . . . . . . . .+-----+. .
                        |NODE6|
                        +-----+
                           |
                        +-----+
                        |NODE7|
   . . . . . . . . . . .+-----+. .
   .                       |     .
   . +-----+            +-----+  .
   . |NODE8|------------|NODE9|  .
   . +-----+            +-----+  .
   .                       |     .
   .Domain2             +------+ .
   .     ---------------|NODE10| .
   .     |              +------+ .
   . +------+. . . . . . . . . . .
     |NODE11|
     +------+
        |
     +------+
     |NODE12|
   . +------+. . . . . . . . . . .
   .    |                        .
   . +------+     +------+       .
   . |NODE14|-----|NODE15|       .
   . +------+     +------+       .
   .        \       |            .
   .         +------+            .
   .         |NODE13|   Domain3  .
   .         +------+            .
   . . . . . . . . . . . . . . . .

   Figure 3: Initial convergence time of information flooding in multi-
                              domain networks




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   Control nodes are represented by vertices and physical links are
   represented by dashed lines.  Border nodes NODE6, NODE7, NODE11 and
   NODE12 connect Domain1, Domain2 and Domain3.

   When all these nodes switch on normally and their interfaces first
   become operational, Hello packets are flooded in the multi-domain
   network to establish neighbor relationships.

   For the three domains in the network as depicted in Figure 3, all
   these nodes are switched on more or less simultaneously, so store the
   same time structure in every node is necessary to record the first
   sending moment of Hello packets.  The earliest sending moment is the
   starting point of the convergence time.

   After the establishment of neighbor relationships, DD packets are
   sent and received to compare the nodes database so as to establish
   adjacency relationships.  And the receiving moments of DD packets
   SHOULD be stored in another time structure in every node.  Then
   choose the latest moment among all receiving moments relating to DD
   packets as the end point of the convergence time of information
   flooding in this scenario.

   So the initial convergence time of information flooding in the multi-
   domain network can be computed by subtracting the starting point from
   the end point.

5.2.  Convergence time of information flooding with LSPs

5.2.1.  Definition

   Convergence time of information flooding with LSPs in multi-domain
   networks comprises two parts: intra-domain convergence time of
   information flooding and inter-domain convergence time of information
   flooding.  While intra-domain convergence time of information
   flooding is further divided into several single domain convergence
   time of information flooding according to the domains the cross-
   domain-LSP traversed through.  And inter-domain convergence time of
   information flooding refers to a time period during which the domain
   border nodes synchronize their information according to RFC1583.

   Every single domain convergence time of information flooding can
   refer to section 4.2.  Note that for source domain the convergence
   time starts at the moment when the LSP ingress node updates its
   information.  Otherwise, for intermediate domains, as well as
   destination domain, the convergence time starts at the moment when
   the ingress node of that domain updates its information with respect
   to the LSP.  All the convergence time end with the last node!_s
   receipt of the updating information.



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   Setting the convergence time of information flooding with LSPs as
   undefined means the ingress node fails to receive the corresponding
   ResvConf message, which MAY indicate resource reservation failures or
   nodes breaking down along the cross-domain LSP.

5.2.2.  Methodology

   The procedure of convergence time of information flooding in multi-
   domain network, as mentioned above, comprises two parts: intra-domain
   convergence time of information flooding and inter-domain convergence
   time of information flooding.  Methodology for convergence time of
   information flooding in single domain has been specified in Section
   4.2.2; and the methodology for inter-domain convergence time of
   information flooding proceeds as follows,

   o  All control nodes in all domains switch on normally;

   o  Initial information synchronization is complete, which means all
      nodes!_ LSDB are up-to-date;

   o  Select an ingress node ID0 and an egress node ID1 in a different
      domain, and create a cross-domain LSP from ID0 to ID1;

   o  Wait until ID0 receives all the corresponding ResvConf messages
      that confirm the completion of resource reservation, ID0 updates
      its LSDB and forms a LSU packet LSU0.  Store a timestamp (T1) at
      ID0 as soon as the LSU packet is sent;

   o  Then the source domain border node receives the LSU packet and
      summarizes the source domain information into an advertisement.
      Then the border node distributes the advertisement to backbone
      area.  Store a timestamp (T2) at the border node as soon as the
      advertisement is distributed;

   o  Another timestamp (T3) SHOULD be stored locally as soon as the
      border node in destination domain receives an advertisement from
      backbone area;

   o  Inter-domain convergence time of information flooding can be
      computed by subtracting two timestamps (T3-T2);

   o  The convergence time of information flooding of the network can
      also be computed by subtracting two timestamps (T3-T1);

   o  If ID0 fails to receive the corresponding ResvConf message in a
      reasonable period of time, the inter-domain convergence time of
      information flooding is set to undefined.




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5.2.3.  Sample


   . . . . . . . . . . . . . . . .
   . +-----+  +-----+  +-----+   .
   . |NODE1|--|NODE2|==|NODE3|   .
   . +-----+  +-----+  +-----+   .
   .    |    /            ||     .
   . +-----+/    +-----+  ||     .
   . |NODE4|-----|NODE5|  ||     .
   . +-----+     +-----+  ||     .
   .                      ||     .
   . Domain1              ||     .
   . . . . . . . . . . .+-----+. .
                        |NODE6|
                        +-----+
                          ||
                        +-----+
                        |NODE7|
   . . . . . . . . . . .+-----+. .
   .                      ||     .
   . +-----+            +-----+  .
   . |NODE8|------------|NODE9|  .
   . +-----+            +-----+  .
   .                      ||     .
   .Domain2             +------+ .
   .     ===============|NODE10| .
   .    ||              +------+ .
   . +------+. . . . . . . . . . .
     |NODE11|
     +------+
        ||
     +------+
     |NODE12|
   . +------+. . . . . . . . . . .
   .    ||                       .
   . +------+     +------+       .
   . |NODE14|=====|NODE15|       .
   . +------+     +------+       .
   .        \       |            .
   .         +------+            .
   .         |NODE13|   Domain3  .
   .         +------+            .
   . . . . . . . . . . . . . . . .

      Figure 4: Convergence time of information flooding with LSPs in
                           multi-domain networks




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   Control nodes are represented by vertices and physical links are
   represented by dashed lines and LSPs are represented by equal signs.
   Border nodes are NODE6, NODE7, NODE11 and NODE12 which connect
   Domain1, Domain2 and Domain3, as shown in Figure 4.

   The cross-domain LSP is NODE2->NODE3->NODE6->NODE7->NODE9->NODE10->NO
   DE11->NODE12->NODE14->NODE15.  When ResvConf message is received from
   every node along this LSP, meaning the resource reservation is
   complete, LSAs flooding begins from the source domain, Domain1.

   NODE2 sends out a LSU packet LSU1 which contains link states changes
   in Domain1, and LSU1 is then flooded in Domain1.  When Domain1's
   border node NODE6 receives LSU1, it not only updates its own database
   but also forms an inter-domain LSU packet LSU12 summarizing Domain1's
   states changes and sends it to Domain2's border node NODE7.  As
   ingress node of partial LSP in Domain2, NODE7 also sends out a LSU
   packet LSU2 which includes link states changes in Domain2 and then
   LSU2 is flooded in Domain2.  Similarly, NODE11 forms an inter-domain
   LSU packet LSU 23 and sends it to NODE12.  NODE12, as ingress node of
   partial LSP in Domain3, forms LSU3 which is then flooded in Domain3.

   LSU1, LSU2 and LSU3 are intra-domain LSU packets while LSU12, LSU23
   are inter-domain LSU packets.

   Time structures are stored in every node along the sending and
   receiving of LSU packets.  Moments related to different LSU packets
   are recorded in different time structures.

   Intra-domain convergence time of information flooding in Domain1 can
   be computed by subtracting the end point, which can be obtain by
   choosing the latest receiving moment in Domain1, from NODE2s sending
   moment.  Similarly, the starting point and end point of the intra-
   domain convergence time of information flooding in Domain2 are NODE7s
   LSU2 sending moment and the latest receiving moment among NODE8,
   NODE9, NODE10 and NODE11.  For Domain3 the starting point and end
   point are NODE11s LSU3 sending moment and the latest receiving moment
   among NODE12, NODE13, NODE14 and NODE15.

   Inter-domain convergence time of information flooding reflects the
   time required to synchronize information among border nodes: NODE6,
   NODE7, NODE11 and NODE12.  So the starting point is NODE6s LSU12
   sending moment while the endpoint is the latest inter-domain LSU
   packets receiving moment.  By subtracting the two moments, inter-
   domain convergence time of information flooding for Domain1, Domain2
   and Domain3 is computed.  Note that in Figure 4, there is only one
   entrance border node and one exit border node between two domains.
   As for Domain1, NODE6 is the only exit node, so the starting point of
   inter-domain convergence time of information flooding is the moment



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   when NODE6 sends LSU12.  In the topology where there are more than
   one exit nodes in the source domain, the starting moment will be the
   earliest LSU12 sending moments among the exit border nodes.

   The convergence time of information flooding in the network can be
   computed by subtracting the following two moments, one is the NODE2s
   sending moment in Domain1, the other is the latest LSU23 receiving
   moment.


6.  Protocol Extension Requirements

6.1.  OSPF-TE Extension Requirements

   The measurement procedure of the initial convergence time of
   information flooding requires the extensions in OSPF-TE protocol.
   During the procedure, sending and receiving moments of Hello packets
   and DD packets need to be recorded.  Corresponding timestamps are
   needed to symbolize the sending and receiving of Hello packets and DD
   packets in every node.

6.2.  RSVP-TE Extension Requirements


7.  Discussion

   The following issues are likely to come up in practice.

   o  The accuracy of convergence time of information flooding depends
      largely on the clock resolution in every node, where time
      structures are stored; so synchronization among all nodes in the
      network is crucial.

   o  Whether a convergence time of information flooding is a real
      number or undefined largely depends on the choosing of the
      reasonable waiting time before the ResvConf is received.  However,
      choosing the waiting time is complicated.  If the time is set too
      short, there will be too much "undefined" convergence time and the
      result does not reflect the network performance properly.
      However, if the time is set too long, time is wasted waiting when
      there are resource reservation failures or breaking down nodes.
      Choose the appropriate waiting time is also depending on the
      network status, if the network is light loaded, the waiting time
      can be set shorter than it is set when the network is heavy
      loaded.






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8.  Security Considerations


9.  Acknowledgement

   We wish to thank Shengwei Meng, and Koubo Wu in the Key Laboratory of
   Information Photonics and Optical Communications (BUPT), Ministry of
   Education, for their valuable comments.  We also wish to thank the
   support from National 863 program.


10.  Normative References

   [RFC1583]  Moy, J., "OSPF Version 2", March 1994.

   [RFC2119]  Bradner, S., "Key words for use in RFC's to Indicate
              Requirement Levels", RFC 2119, March 1997.

   [RFC2205]  Braden, R., Zhang, L., Berson, S., Herzog, S., and S.
              Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
              Functional Specification", RFC 2205, September 1997.

   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", September 2003.

   [RFC3945]  Mannie, E., "Generalized Multi-Protocol Label Switching
              (GMPLS) Architecture", October 2004.

   [RFC5151]  Farrel, A., Ayyangar, A., and JP. Vasseur, "Inter-Domain
              MPLS and GMPLS Traffic Engineering -- Resource Reservation
              Protocol-Traffic Engineering (RSVP-TE) Extensions",
              February 2008.

   [RFC5152]  Vasseur, JP., Ayyangar, A., and R. Zhang, "A Per-Domain
              Path Computation Method for Establishing Inter-Domain
              Traffic Engineering (TE) Label Switched Paths (LSPs)",
              February 2008.


Appendix A.  author

   Jie Zhang

   Beijing University of Post and Telecommunication

   No.10,Xitucheng Road,Haidian District

   Beijing 100876



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   China

   Phone: +8613911060930

   Email: lgr24@bupt.edu.cn


Authors' Addresses

   Min Zhang
   Beijing University of Post and Telecommunication
   No.10,Xitucheng Road,Haidian District
   Beijing  100876
   P.R.China

   Phone: +8613910621756
   Email: mzhang@bupt.edu.cn


   Hui Ding
   Beijing University of Post and Telecommunication
   No.10,Xitucheng Road,Haidian District
   Beijing  100876
   P.R.China

   Phone: +8613426082796
   Email: dinghui.ei@gmail.com


   Yongli Zhao
   Beijing University of Post and Telecommunication
   No.10,Xitucheng Road,Haidian District
   Beijing  100876
   P.R.China

   Phone: +8613811761857
   Email: yufengx386@gmail.com


   Haiyi Zhang
   China Academy of Telecommunication Research, MIIT, China.
   No.52 Hua Yuan Bei Lu,Haidian District
   Beijing  100083
   P.R.China

   Phone: +861062300100
   Email: zhanghaiyi@mail.ritt.com.cn




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   Yunbin Xu
   China Academy of Telecommunication Research, MIIT, China.
   No.52 Hua Yuan Bei Lu,Haidian District
   Beijing  100083
   P.R.China

   Phone: +8613681485428
   Email: xuyunbin@mail.ritt.com.cn











































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