ccamp G. Xie Internet-Draft W. Sun Intended status: Standards Track Shanghai Jiao Tong University Expires: August 26, 2007 G. Zhang China Academy of Telecommunication Research,MII. J. Han IXIA X. Wei Fiberhome J. Gao Huawei February 22, 2007 Label Switched Path (LSP) Dynamical Provisioning Performance Metrics in Generalized MPLS Networks draft-xie-ccamp-lsp-dppm-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of 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- Drafts. 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. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 26, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Xie, et al. Expires August 26, 2007 [Page 1] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 Abstract Generalized Multi-Protocol Label Switching (GMPLS) is one of the most promising candidate technologies for the future data transmission network. The GMPLS has been developed to control and cooperate different kinds of network elements, such as conventional routers, switches, Dense Wavelength Division Multiplexing (DWDM) systems, Add- Drop Multiplexors (ADMs), photonic cross-connects (PXCs), optical cross-connects (OXCs), etc. Dynamic provisioning ability of these physically diverse devices differs from each other drastically. At the same time, the need for dynamically provisioned connections is increasing because optical networks are being deployed in metro area. As different applications have varied requirements in the provisioning performance of optical networks, it is imperative to define standardized metrics and procedures such that the performance of networks and application needs can be mapped to each other. This document provides a series of performance metrics to evaluate the dynamic LSP provisioning performance in GMPLS networks, specifically the dynamical LSP setup/release performance. These metrics can depict the features of the GMPLS network in LSP dynamic provisioning. Xie, et al. Expires August 26, 2007 [Page 2] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Conventions Used in This Document . . . . . . . . . . . . . . 6 3. Overview of Performance Metrics . . . . . . . . . . . . . . . 7 4. A Singleton Definition for Unidirectional LSP Setup Delay . . 8 4.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2. Metric Name . . . . . . . . . . . . . . . . . . . . . . . 8 4.3. Metric Parameters . . . . . . . . . . . . . . . . . . . . 8 4.4. Metric Units . . . . . . . . . . . . . . . . . . . . . . . 9 4.5. Definition . . . . . . . . . . . . . . . . . . . . . . . . 9 4.6. Discussion . . . . . . . . . . . . . . . . . . . . . . . . 9 4.7. Methodologies . . . . . . . . . . . . . . . . . . . . . . 10 5. A Definition for Samples of Unidirectional LSP Setup Delay . . 11 5.1. Metric Name . . . . . . . . . . . . . . . . . . . . . . . 11 5.2. Metric Parameters . . . . . . . . . . . . . . . . . . . . 11 5.3. Metric Units . . . . . . . . . . . . . . . . . . . . . . . 11 5.4. Definition . . . . . . . . . . . . . . . . . . . . . . . . 11 5.5. Discussion . . . . . . . . . . . . . . . . . . . . . . . . 12 5.6. Methodologies . . . . . . . . . . . . . . . . . . . . . . 12 6. A Singleton Definition for Bidirectional LSP Setup Delay . . . 13 6.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 13 6.2. Metric Name . . . . . . . . . . . . . . . . . . . . . . . 14 6.3. Metric Parameters . . . . . . . . . . . . . . . . . . . . 14 6.4. Metric Units . . . . . . . . . . . . . . . . . . . . . . . 14 6.5. Definition . . . . . . . . . . . . . . . . . . . . . . . . 14 6.6. Discussion . . . . . . . . . . . . . . . . . . . . . . . . 15 6.7. Methodologies . . . . . . . . . . . . . . . . . . . . . . 15 7. A Definition for Samples of Bidirectional LSP Setup Delay . . 17 7.1. Metric Name . . . . . . . . . . . . . . . . . . . . . . . 17 7.2. Metric Parameters . . . . . . . . . . . . . . . . . . . . 17 7.3. Metric Units . . . . . . . . . . . . . . . . . . . . . . . 17 7.4. Definition . . . . . . . . . . . . . . . . . . . . . . . . 17 7.5. Discussion . . . . . . . . . . . . . . . . . . . . . . . . 18 7.6. Methodologies . . . . . . . . . . . . . . . . . . . . . . 18 8. A Singleton Definition for LSP Graceful Release Delay . . . . 19 8.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 19 8.2. Metric Name . . . . . . . . . . . . . . . . . . . . . . . 19 8.3. Metric Parameters . . . . . . . . . . . . . . . . . . . . 19 8.4. Metric Units . . . . . . . . . . . . . . . . . . . . . . . 19 8.5. Definition . . . . . . . . . . . . . . . . . . . . . . . . 19 8.6. Discussion . . . . . . . . . . . . . . . . . . . . . . . . 20 8.7. Methodologies . . . . . . . . . . . . . . . . . . . . . . 21 9. A Definition for Samples of LSP Graceful Release Delay . . . . 23 9.1. Metric Name . . . . . . . . . . . . . . . . . . . . . . . 23 9.2. Metric Parameters . . . . . . . . . . . . . . . . . . . . 23 9.3. Metric Units . . . . . . . . . . . . . . . . . . . . . . . 23 9.4. Definition . . . . . . . . . . . . . . . . . . . . . . . . 23 Xie, et al. Expires August 26, 2007 [Page 3] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 9.5. Discussion . . . . . . . . . . . . . . . . . . . . . . . . 24 9.6. Methodologies . . . . . . . . . . . . . . . . . . . . . . 24 10. Some Statistics Definitions for Metrics to Report . . . . . . 25 10.1. The Minimum of Metric . . . . . . . . . . . . . . . . . . 25 10.2. The Median of Metric . . . . . . . . . . . . . . . . . . . 25 10.3. The percentile of Metric . . . . . . . . . . . . . . . . . 25 10.4. The failure probability . . . . . . . . . . . . . . . . . 25 11. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 26 12. Security Considerations . . . . . . . . . . . . . . . . . . . 27 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 28 14. Normative References . . . . . . . . . . . . . . . . . . . . . 29 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 30 Intellectual Property and Copyright Statements . . . . . . . . . . 32 Xie, et al. Expires August 26, 2007 [Page 4] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 1. Introduction Generalized Multi-Protocol Label Switching (GMPLS) is one of the most promising candidate technologies for the future data transmission network. The GMPLS has been developed to control and cooperate different kinds of network elements, such as conventional routers, switches, Dense Wavelength Division Multiplexing (DWDM) systems, Add- Drop Multiplexors (ADMs), photonic cross-connects (PXCs), optical cross-connects (OXCs), etc. Dynamic provisioning ability of these physically diverse devices differs from each other drastically. As more and more applications are seeking to use GMPLS networks as their underlying transport network, and increasingly in a dynamic way, the need is growing for measuring and characterizing the performance of LSP provisioning in GMPLS networks, such that requirement from applications and the provisioning capability of the network can be mapped to each other. This draft intends to define performance metrics that can be used to depict the dynamic LSP provisioning performance of GMPLS networks. Xie, et al. Expires August 26, 2007 [Page 5] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 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]. Xie, et al. Expires August 26, 2007 [Page 6] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 3. Overview of Performance Metrics In this memo, to depict the dynamic LSP provisioning performance of a GMPLS network, we define 3 performance metrics: unidirectional LSP setup delay, bidirectional LSP setup delay, and LSP graceful release delay. The latency of the LSP setup/release signal is similar to the Round-trip Delay in IP networks. So we refer the structures and notions introduced and discussed in the IPPM Framework document, [RFC2330] [RFC2679] [RFC2681]. The reader is assumed to be familiar with the notions in those documents. Xie, et al. Expires August 26, 2007 [Page 7] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 4. A Singleton Definition for Unidirectional LSP Setup Delay This part defines a metric for unidirectional Label Switched Path setup delay across a GMPLS network. 4.1. Motivation Unidirectional Label Switched Path setup delay is useful for several reasons: o LSP setup delay is an important metric that depicts the provisioning performance of a GMPLS network. Longer LSP setup delay will incur higher overhead for the requesting application, especially when the LSP duration is comparable to the LSP setup delay. o The minimum value of this metric provides an indication of the delay that will likely be experienced when the LSP traversed the shortest route at the lightest load in the control plane. As the delay itself consists of several components, such as link propagation delay and nodal processing delay, this metric also reflects the status of control plane. For example, for LSPs traversing the same route, longer setup delays may suggest congestion in the control channel or high control element load. For this reason, this metric is useful for testing and diagnostic purposes. o LSP setup delay variance has different impact on to applications. Erratic variation in LSP setup delay makes it difficult to support applications that has stringent setup delay requirement. The measurement of unidirectional LSP setup delay instead of bidirectional LSP setup delay is motivated by the following factors: o Some applications may only use unidirectional LSPs rather than bidirectional ones. For example, content delivery services in multicast method (IPTV) only use unidirectional LSPs. 4.2. Metric Name Unidirectional LSP setup delay 4.3. Metric Parameters o ID0, the ingress LSR ID o ID1, the egress LSR ID Xie, et al. Expires August 26, 2007 [Page 8] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 o T, a time 4.4. Metric Units The value of unidirectional LSP setup delay is either a real number, or an undefined (informally, infinite) number of seconds. 4.5. Definition The unidirectional LSP setup delay from the ingress node to the egress node [RFC3945] at T is dT means that ingress node sent the first bit of a PATH message packet to egress node at wire-time T, and that the ingress node received the last bit of responding RESV message packet from egress node at wire-time T+dT in the unidirectional LSP setup case. The unidirectional LSP setup delay from the ingress node to the egress node at T is undefined (informally, infinite), means that ingress node sent the first bit of PATH message packet to egress node at wire-time T and that ingress node did not receive the corresponding RESV message within a reasonable period of time. 4.6. Discussion The following issues are likely to come up in practice: o The accuracy of unidirectional LSP setup delay at time T depends on the clock resolution in the ingress node; but synchronization between the ingress node and egress node is not required since unidirectional LSP setup uses two-way signaling o A given methodology will have to include a way to determine whether a latency value is infinite or whether it is merely very large. Simple upper bounds could be used. But the GMPLS network accommodates many kinds of devices. For example, some photonic cross-connects (PXCs) have to move the micro mirrors. This physical motion may take several milliseconds. But the common electronic switches finish the nodal process within several microseconds. So the unidirectional LSP setup delay varies drastically from a network to another. In practice, the upper bound should be chose carefully. o If ingress node sent out the PATH message to set up LSP, but never receive corresponding RESV message, unidirectional LSP setup delay is deemed to be infinite. o If ingress node sent out the PATH message to set up LSP but receive PathErr message, unidirectional LSP setup delay is also Xie, et al. Expires August 26, 2007 [Page 9] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 deemed to be infinite. There are many possible reasons for this case. For example, the PATH message has invalid parameters or the network has not enough resource to set up the requested LSP, etc. 4.7. Methodologies Generally the methodology would proceed as follows: o Make sure that the network has enough resource to set up the requested LSP. o At the ingress node, form the PATH message according to the LSP requirements. A timestamp (T1) may be stored locally in the ingress node when the PATH message packet is sent towards the egress node. o If the corresponding RESV message arrives within a reasonable period of time, take the timestamp (T2) as soon as possible upon the receipt of the message. By subtracting the two timestamps, an estimate of unidirectional LSP setup delay (T2 -T1) can be computed. o If the corresponding RESV message fails to arrive within a reasonable period of time, the unidirectional LSP setup delay is deemed to be undefined (informally, infinite). Note that the 'reasonable' threshold of is a parameter of the methodology. o If the corresponding response message is PathErr, the unidirectional LSP setup delay is deemed to be undefined (informally, infinite). Xie, et al. Expires August 26, 2007 [Page 10] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 5. A Definition for Samples of Unidirectional LSP Setup Delay In the previous part, we define the singleton metric of unidirectional LSP setup delay. Now we define how to get one particular sample of unidirectional LSP setup delay. Sampling is to select a particular potion of singleton values of the given parameters. Like the [RFC2330], we use Poisson sampling as an example. 5.1. Metric Name Unidirectional LSP setup delay sample 5.2. Metric Parameters o ID0, the ingress LSR ID o ID1, the egress LSR ID o T0, a time o Tf, a time o Lambda, a rate in reciprocal seconds o Td, the 'reasonable' threshold 5.3. Metric Units A sequence of pairs; the elements of each pair are: o T, a time, and o dT, either a real number or an undefined number of seconds. The values of T in the sequence are monotonically increasing. Note that T would be a valid parameter to unidirectional LSP setup delay sample, and that dT would be a valid value of unidirectional LSP setup delay. 5.4. Definition Given T0, Tf, and lambda, we compute a pseudo-random Poisson process beginning at or before T0, with average arrival rate lambda, and ending at or after Tf. Those time values greater than or equal to T0 and less than or equal to Tf are then selected. At each of the times in this process, we obtain the value of unidirectional LSP setup delay sample at this time. The value of the sample is the sequence Xie, et al. Expires August 26, 2007 [Page 11] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 made up of the resulting pairs. If there are no such pairs, the sequence is of length zero and the sample is said to be empty. 5.5. Discussion The parameter lambda should be carefully chosen. If the rate is too large, too frequent LSP setup/release procedure results in high overhead in the control plane. In turn, the high overhead will increase unidirectional LSP setup delay. On the other hand if the rate is too small, the sample could not completely reflect the dynamic provisioning performance of the GMPLS network. The appropriate lambda value depends on the given network. 5.6. Methodologies Generally the methodology would proceed as follows: o The selection of specific times, using the specified Poisson arrival process, and o Set up the LSP as the methodology for the singleton unidirectional LSP setup delay, and obtain the value of unidirectional LSP setup delay o Release the LSP, and wait for the next Poisson arrival process Note that: it is possible that before the previous LSP release procedure completes, the next Poisson arrival process has arrived and the LSP setup procedure has been initiated. If there is resource contention between the two LSPs, the LSP setup may fail. Xie, et al. Expires August 26, 2007 [Page 12] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 6. A Singleton Definition for Bidirectional LSP Setup Delay Bidirectional optical LSPs (or lightpaths) are seen as a requirement for most optical networking service. GMPLS allows establishment of bi-directional symmetric LSPs (not of asymmetric LSPs). A symmetric bidirectional LSP has the same traffic engineering requirements including fate sharing, protection and restoration, LSRs, and resource requirements (e.g., delay and delay variance) in either direction. Compared with the approach of establishing a bidirectional LSP using two unidirectional LSP, the bidirectional LSP has the following advantages: o Reduces the setup delay to one ingress-egress round trip time plus processing time in the nodes en-route; o Reduces the signal overhead in the control plane; o Allows suggesting a label by an upstream node to reduce the setup delay. This part defines a metric for bidirectional LSP setup delay across a GMPLS network. 6.1. Motivation Bidirectional Label Switched Path setup delay is useful for several reasons: o LSP setup delay is an important metric that depicts the provisioning performance of a GMPLS network. Longer LSP setup delay will incur higher overhead for the requesting application, especially when the LSP duration is comparable to the LSP setup delay. Thus, measuring the setup delay is important for applications scheduling. o The minimum value of this metric provides an indication of the delay that will likely be experienced when the LSP traversed the shortest route at the lightest load in the control plane. As the delay itself consists of several components, such as link propagation delay and nodal processing delay, this metric also reflects the status of control plane. For example, for LSPs traversing the same route, longer setup delays may suggest congestion in the control channel or high control element load. For this reason, this metric is useful for testing and diagnostic purposes. Xie, et al. Expires August 26, 2007 [Page 13] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 o LSP setup delay variance has different impact on to applications. Erratic variation in LSP setup delay makes it difficult to support applications that has stringent setup delay requirement. The measurement of bidirectional LSP setup delay instead of unidirectional LSP setup delay is motivated by the following factors: o Bidirectional LSPs are seen as a requirement for many GMPLS network while the LSPs are unidirectional in nature in the MPLS network. For most applications, the communication is bidirectional. So bidirectional LSP delay is necessary and more reasonable than unidirectional LSP delay. 6.2. Metric Name Bidirectional LSP setup delay 6.3. Metric Parameters o ID0, the ingress LSR ID o ID1, the egress LSR ID o T, a time 6.4. Metric Units The value of bidirectional LSP setup delay is either a real number, or an undefined (informally, infinite) number of seconds. 6.5. Definition For a real number dT, the bidirectional LSP setup delay from ingress node to egress node at T is dT, means that ingress node sent out the first bit of a PATH message including an Upstream Label [RFC3473] heading for egress node at wire-time T, egress node received that packet, then immediately sent a RESV message packet back to ingress node, and that ingress node received the last bit of that packet at wire-time T+dT. The bidirectional LSP setup delay from ingress node to egress node at T is undefined (informally, infinite), means that ingress node sent the first bit of PATH message to egress node at wire-time T and that (either egress node did not receive the packet, egress node did not send corresponding RESV message packet in response, or) ingress node did not receive that response packet. Xie, et al. Expires August 26, 2007 [Page 14] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 6.6. Discussion The following issues are likely to come up in practice: o The accuracy of bidirectional LSP setup delay depends on the clock resolution in the ingress node; but synchronization between the ingress node and egress node is not required since bidirectional LSP setup uses two-way signaling. o A given methodology will have to include a way to determine whether a latency value is infinite or whether it is merely very large. Simple upper bounds could be used. But the GMPLS network accommodates many kinds of devices. For example, some photonic cross-connects (PXCs) have to move the micro mirrors. This physical motion may take several milliseconds. But the common electronic switches finish the nodal process within several microseconds. So the bidirectional LSP setup delay varies drastically from a network to another. In the process of bidirectional LSP setup, if the downstream node overrides the label suggested by the upstream node, the setup delay will also increase obviously. Thus, in practice, the upper bound should be chosen carefully. o If the ingress node sent out the PATH message to set up the LSP, but never receive the corresponding RESV message, bidirectional LSP setup delay is deemed to be infinite. o If the ingress node sent out the PATH message to set up the LSP, but receive PathErr message, bidirectional LSP setup delay is also deemed to be infinite. There are many possible reasons for this case. For example, the PATH message has invalid parameters or the network has not enough resource to set up the requested LSP. 6.7. Methodologies Generally the methodology would proceed as follows: o Make sure that the network has enough resource to set up the requested LSP. o At the ingress node, form the PATH message (including the Upstream Label or suggested label) according to the LSP requirements. A timestamp (T1) may be stored locally in the ingress node when the PATH message packet is sent towards the egress node. o If the corresponding RESV message arrives within a reasonable period of time, take the final timestamp (T2) as soon as possible upon the receipt of the message. By subtracting the two Xie, et al. Expires August 26, 2007 [Page 15] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 timestamps, an estimate of bidirectional LSP setup delay (T2 -T1) can be computed. o If the corresponding RESV message fails to arrive within a reasonable period of time, the bidirectional LSP setup delay is deemed to be undefined (informally, infinite). Note that the 'reasonable' threshold is a parameter of the methodology. o If the corresponding response message is PathErr, the bidirectional LSP setup delay is deemed to be undefined (informally, infinite). Xie, et al. Expires August 26, 2007 [Page 16] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 7. A Definition for Samples of Bidirectional LSP Setup Delay In the previous part, we define the singleton metric of bidirectional LSP setup delay. Now we define how to get one particular sample of bidirectional LSP setup delay. We also use Poisson sampling as an example. 7.1. Metric Name Bidirectional LSP setup delay sample 7.2. Metric Parameters o ID0, the ingress LSR ID o ID1, the egress LSR ID o T0, a time o Tf, a time o Lambda, a rate in reciprocal seconds o Td, the 'reasonable' threshold 7.3. Metric Units A sequence of pairs; the elements of each pair are: o T, a time, and o dT, either a real number or an undefined number of seconds. The values of T in the sequence are monotonical increasing. Note that T would be a valid parameter to bidirectional LSP setup delay sample, and that dT would be a valid value of bidirectional LSP setup delay. 7.4. Definition Given T0, Tf, and lambda, we compute a pseudo-random Poisson process beginning at or before T0, with average arrival rate lambda, and ending at or after Tf. Those time values greater than or equal to T0 and less than or equal to Tf are then selected. At each of the times in this process, we obtain the value of unidirectional LSP setup delay sample at this time. The value of the sample is the sequence made up of the resulting pairs. If there are no such pairs, the sequence is of length zero and the Xie, et al. Expires August 26, 2007 [Page 17] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 sample is said to be empty. 7.5. Discussion The parameter lambda should be carefully chosen. If the rate is too large, too frequent LSP setup/release procedure results in high load in the control plane, which will in turn increase unidirectional LSP setup delay. On the other hand if the rate is too small, the sample could not completely reflect the dynamic provisioning performance of the GMPLS network. The appropriate lambda value depends on the given network. 7.6. Methodologies Generally the methodology would proceed as follows: o Setup the LSP to be deleted o The selection of specific times, using the specified Poisson arrival process, and o Release the LSP as the methodology for the singleton LSP graceful release delay, and obtain the value of LSP graceful release delay o Setup the LSP, and restart the Poisson arrival process, wait for the next Poisson arrival process Note that: it is possible that before the previous LSP release procedure completes, the next Poisson arrival process has arrived and the LSP setup procedure has been initiated. If there is resource contention between these two LSPs, the LSP setup may fail. Xie, et al. Expires August 26, 2007 [Page 18] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 8. A Singleton Definition for LSP Graceful Release Delay There are two different kinds of LSP release mechanisms in the GMPLS network: graceful release and forceful release. As a matter of fact, the forceful release employs PathErr message to tear down the LSP. Memo in current version has not taken forceful LSP release procedure into account. 8.1. Motivation LSP graceful release delay is useful for several reasons: o The LSP graceful release delay is part of the total cost of dynamic LSP provisioning. For some short duration applications, the LSP tear down time can not be ignored o The LSP graceful release procedure is more reasonable for GMPLS network, particularly the optical networks. Since it doesn't trigger restoration/protection, it is "alarm-free connection deletion" in [RFC4208]. 8.2. Metric Name LSP graceful release delay 8.3. Metric Parameters o ID0, the ingress LSR ID o ID1, the egress LSR ID o T, a time 8.4. Metric Units The value of LSP graceful release delay is either a real number, or an undefined (informally, infinite) number of seconds. 8.5. Definition There are two different LSP graceful release procedures, one is initiated by the ingress node, and another is initiated by egress node. The two procedures are depicted in the [RFC3473]. We define the graceful LSP release delay for these two procedures separately. For a real number dT, the LSP graceful release delay from ingress node to egress node at T is dT, means that ingress node sent the first bit of a PATH message including Admin Status Object with Xie, et al. Expires August 26, 2007 [Page 19] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 setting the Reflect (R) and Delete (D) bits to egress node at wire- time T, that egress node received that packet, then immediately sent a RESV message including Admin Status Object with the Delete (D) bit set back to ingress node. The ingress node sends out PathTear downstream to remove the LSP, and egress node received the last bit of PathTear packet at wire-time T+dT. The LSP graceful release delay from ingress node to egress node at T is undefined (informally, infinite), means that ingress node sent the first bit of PATH message to egress node at wire-time T and that (either egress node did not receive the PATH packet, egress node did not send corresponding RESV message packet in response, ingress node did not receive that RESV packet, or) the egress did not receive the PathTear. The LSP graceful release delay from egress node to ingress node at T is dT, means that egress node sent the first bit of a RESV message including Admin Status Object with setting the Reflect (R) and Delete (D) bits to ingress node at wire-time T, that ingress node received the packet, then immediately sent a PathTear message downstream to egress node. The ingress node sends out PathTear downstream to remove the LSP, and egress node received the last bit of PathTear packet at wire-time T+dT. The LSP graceful release delay from egress node to ingress node at T is undefined (informally, infinite), means that egress node sent the first bit of RESV message including Admin Status Object with setting the Reflect (R) and Delete (D) bits to ingress node at wire-time T and that (either ingress node did not receive the RESV packet, ingress node did not send PathTear message packet in response or) the egress did not receive the PathTear. 8.6. Discussion The following issues are likely to come up in practice: o In the first (second) circumstance, the accuracy of LSP graceful release delay at time T depends on the clock resolution in the ingress (egress) node. In the first circumstance, synchronization between the ingress node and egress node is required; but not in the second circumstance; o A given methodology has to include a way to determine whether a latency value is infinite or whether it is merely very large. Simple upper bounds could be used. But the upper bound should be chosen carefully in practice; Xie, et al. Expires August 26, 2007 [Page 20] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 o In the first circumstance, if ingress node sent out PATH message including Admin Status Object with the Reflect (R) and Delete (D) bits set to initiate LSP graceful release, but never receive corresponding RESV message, LSP graceful release delay is deemed to be infinite. In the second circumstance, if egress node sent out RESV message including Admin Status Object with the Reflect (R) and Delete (D) bits set to initiate LSP graceful release, but never receive corresponding PathTear message, LSP graceful release delay is deemed to be infinite; o It is possible that some node(s) along an LSP will not support the Admin Status Object. In the case of a non-supporting intermediate node(s), the object will pass through the node(s) unmodified and normal processing can continue. In the case of a non-supporting ingress/egress node, the Admin Status Object will not be reflected back in the RESV Message. To support the case of a non-supporting ingress/egress node, the ingress (egress in the second circumstance) SHOULD only wait a configurable period of time for the updated Admin Status Object in a RESV message. Once the period of time has elapsed, the ingress (egress in the second circumstance) node sends out a PathTear message to delete LSP. 8.7. Methodologies In the first circumstance, the methodology would proceed as follows: o Make sure the LSP to be deleted is set up; o At the egress node, form the RESV message including Admin Status Object with the Reflect (R) and Delete (D) bits set. A timestamp (T1) may be stored locally in the egress node when the PATH message packet is sent towards the ingress node; o Intermediate nodes process the Admin Status Object as described in [RFC2330], and forward the PATH message to the ingress node; o Upon receiving the Admin Status Object with the Reflect (R) and Delete (D) bits set in the RESV message, the ingress node sends a PathTear message downstream to remove the LSP; o When the egress node receive the Admin Status Object with the Delete (D) bit set in the RESV message, the ingress node sends a PathTear message to remove the LSP; o When the egress node receives the PathTear message, take a timestamp (T2) as soon as possible. The LSP graceful release delay (T2-T1) is this timestamp minus the initial one. Xie, et al. Expires August 26, 2007 [Page 21] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 In the second circumstance, the methodology would proceed as follows: o Make sure the LSP to be deleted is set up; o At the initiator node (egress node in this case), form the RESV message including Admin Status Object with the Reflect (R) and Delete (D) bits set. A timestamp may be stored locally in the initiator node when the PATH message packet is sent towards the terminator node; o Intermediate nodes process the Admin Status Object as described in [RFC2330], and forward the PATH message to the terminator node; o Upon receiving the Admin Status Object with the Reflect (R) and Delete (D) bits set in the RESV message, the terminator node sends a PathTear message downstream to remove the LSP; o When the initiator node receives the PathTear message, take a timestamp as soon as possible. The LSP graceful release delay is this timestamp minus the initial one. Xie, et al. Expires August 26, 2007 [Page 22] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 9. A Definition for Samples of LSP Graceful Release Delay In the previous part, we define the singleton metric of LSP graceful release delay. Now we define how to get one particular sample of LSP graceful release delay. We also use Poisson sampling as an example. 9.1. Metric Name LSP graceful release delay sample 9.2. Metric Parameters o ID0, the ingress LSR ID o ID1, the egress LSR ID o T0, a time o Tf, a time o Lambda, a rate in reciprocal seconds o Td, the 'reasonable' threshold 9.3. Metric Units A sequence of pairs; the elements of each pair are: o T, a time, and o dT, either a real number or an undefined number of seconds. The values of T in the sequence are monotonical increasing. Note that T would be a valid parameter to LSP graceful release delay sample and that dT would be a valid value of LSP graceful release delay. 9.4. Definition Given T0, Tf, and lambda, we compute a pseudo-random Poisson process beginning at or before T0, with average arrival rate lambda, and ending at or after Tf. Those time values greater than or equal to T0 and less than or equal to Tf are then selected. At each of the times in this process, we obtain the value of LSP graceful release delay sample at this time. The value of the sample is the sequence made up of the resulting pairs. If there are no such pairs, the sequence is of length zero and the sample is said to be empty. Xie, et al. Expires August 26, 2007 [Page 23] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 9.5. Discussion The parameter lambda should be carefully chosen. If the rate is too large, too frequent LSP setup/release procedure results in high overhead in the control plane. In turn, the high overhead will increase unidirectional LSP setup delay. On the other hand if the rate is too small, the sample could not completely reflect the dynamic provisioning performance of the GMPLS network. The appropriate lambda value depends on the given network. 9.6. Methodologies Generally the methodology would proceed as follows: o Setup the LSP to be deleted o The selection of specific times, using the specified Poisson arrival process, and o Release the LSP as the methodology for the singleton LSP graceful release delay, and obtain the value of LSP graceful release delay o Setup the LSP, and restart the Poisson arrival process, wait for the next Poisson arrival process Xie, et al. Expires August 26, 2007 [Page 24] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 10. Some Statistics Definitions for Metrics to Report Given the samples of the performance metric, we now offer several statistics of these samples to report. From these statistics, we can draw some useful conclusions of a GMPLS network. The value of these metrics is either a real number, or an undefined (informally, infinite) number of seconds. In the following discussion, we only consider the finite values. 10.1. The Minimum of Metric The minimum of metric is the minimum of all the dT values in the sample. In computing this, undefined values are treated as infinitely large. Note that this means that the minimum could thus be undefined (informally, infinite) if all the dT values are undefined. In addition, the metric minimum is undefined if the sample is empty. 10.2. The Median of Metric Metric median is the median of the dT values in the given sample. In computing the median, the undefined values are not counted in. 10.3. The percentile of Metric Given a metric and a percent X between 0% and 100%, the Xth percentile of all the dT values in the sample. In addition, the unidirectional LSP setup delay percentile is undefined if the sample is empty. Example: suppose we take a sample and the results are: Stream1 = < , , , , > Then the 50th percentile would be 110 msec, since 90 msec and 100 msec are smaller, and 110 and 500 msec are larger (undefined values are not counted in). 10.4. The failure probability In the process of LSP setup/release, it may fail for some reason. The failure probability is the ratio of the failure times to the total times. Xie, et al. Expires August 26, 2007 [Page 25] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 11. Discussion It is worthwhile to point out that: o The unidirectional/bidirectional LSP setup delay is one ingress- egress round trip time plus processing time. But in the draft, unidirectional/bidirectional LSP setup delay has not taken the processing time in the end nodes (ingress or/and egress) into account. The timestamp T2 is taken after the endpoint node receives it. Actually, the last node has to take some time to process local procedure. Similarly, in the LSP graceful release delay, the memo has not considered the processing time in the endpoint node. o All these metrics are defined from the point of control plane's view. In fact, the control plane and data plane are not always synchronized. In some cases, the LSPs have been set up in the control plane. But the data can not be forwarded immediately. The unidirectional/bidirectional LSP setup delay in the data plane is longer than in the control plane. Xie, et al. Expires August 26, 2007 [Page 26] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 12. Security Considerations The security considerations pertaining to the original RSVP protocol [RFC2205] and its TE extensions [RFC3209] remain relevant. Xie, et al. Expires August 26, 2007 [Page 27] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 13. Acknowledgements This document contains ideas as well as text that have appeared in existing IETF documents. The authors wish to thank G. Almes, S. Kalidindi and M. Zekauskas. We also wish to thank Weisheng Hu, Yaohui Jin and Wei Guo in the state key laboratory of advanced optical communication systems and networks for the valuable comments. We also wish to thank the support from NSFC and 863 program of China. Xie, et al. Expires August 26, 2007 [Page 28] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 14. Normative References [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. [RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis, "Framework for IP Performance Metrics", RFC 2330, May 1998. [RFC2679] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way Delay Metric for IPPM", RFC 2679, September 1999. [RFC2681] Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip Delay Metric for IPPM", RFC 2681, September 1999. [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. [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching (GMPLS) Architecture", RFC 3945, October 2004. [RFC4208] Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter, "Generalized Multiprotocol Label Switching (GMPLS) User- Network Interface (UNI): Resource ReserVation Protocol- Traffic Engineering (RSVP-TE) Support for the Overlay Model", RFC 4208, October 2005. Xie, et al. Expires August 26, 2007 [Page 29] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 Authors' Addresses Guowu Xie Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 CN Phone: +86 21 3420 4596 Email: blithe@sjtu.edu.cn Weiqiang Sun Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 CN Phone: +86 21 3420 5359 Email: sunwq@sjtu.edu.cn Guoying Zhang China Academy of Telecommunication Research,MII. Beijing 200240 CN Phone: +86 1068094272 Email: zhangguoying@mail.ritt.com.cn Jianghui Han IXIA Oriental Kenzo Plaza 8M,48 Dongzhimen Wai Street,Dongcheng District Beijing 200240 CN Phone: +86 13801156004 Email: JHan@ixiacom.com Xie, et al. Expires August 26, 2007 [Page 30] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 Xueqing Wei Fiberhome Telecommunicaiton Technology Co.,Ltd. Wuhan CN Phone: +86 13871127882 Email: xqwei@fiberhome.com.cn Jianhua Gao Huawei Technologies Co., LTD. CN Phone: +86 755 28973237 Email: gjhhit@huawei.com Xie, et al. Expires August 26, 2007 [Page 31] Internet-Draft LSP Dynamical PPM in GMPLS Networks February 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Xie, et al. Expires August 26, 2007 [Page 32]