Network Working Group J. T. Hao Internet-Draft Huawei Technologies Co., Ltd Intended status: Informational P. Maheshwari Expires: November 13, 2015 Bharti Airtel Ltd. R. Huang L. Andersson M. Chen Huawei Technologies Co., Ltd May 12, 2015 Architecture of MPLS/IP Network with Hardened Pipes draft-hao-mpls-ip-hard-pipe-02.txt Abstract This document is intended to become an Informational RFC on the independent stream. The document does not specify any new protocol or procedures. It does explain how the MPLS standards implementation, has been deployed and operated to meet the requirements from operators that offer traditional Virtual Leased Line services. This document describes an MPLS/IP network that has an infrastructure that can be separated into two or more strata. For the implementation described in this document the infrastructure has been separated into two strata. One for the 'Hard Pipes', called the 'Hard Pipe Stratum". And one for the normal IP/MPLS traffic - called the 'Normal IP/MPLS stratum'. This document introduces the concept of "Hard Pipes", a Hard Pipe is an MPLS Label Switched Path (LSP) or a Pseudowire (PW) with a bandwidth that is guaranteed and can neither be exceeded nor infringed upon. The Hard Pipe stratum does not use statistical multiplexing, for the LSPs and PWs setup within this stratum the bandwidth are guaranteed end to end. 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). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. T. Hao, et al. Expires November 13, 2015 [Page 1] Internet-Draft Hard IP Pipes May 2015 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." This Internet-Draft will expire on November 13, 2015. 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 1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4 2. The strata network . . . . . . . . . . . . . . . . . . . . . 5 2.1. The Physical Network . . . . . . . . . . . . . . . . . . 5 2.2. The Hard Pipe stratum . . . . . . . . . . . . . . . . . . 6 2.3. The Normal IP/MPLS stratum . . . . . . . . . . . . . . . 7 2.4. Stratum Networks . . . . . . . . . . . . . . . . . . . . 8 3. Configuring the Leased Lines in Hard Pipe Stratum . . . . . . 8 4. Efficient State Management . . . . . . . . . . . . . . . . . 10 4.1. State in the Forwarding Plane . . . . . . . . . . . . . . 10 4.2. State in the NMS . . . . . . . . . . . . . . . . . . . . 10 4.3. Annotations for Configuring Leased Lines . . . . . . . . 10 5. Setting Up Leased Lines . . . . . . . . . . . . . . . . . . . 12 6. Leased Line protection . . . . . . . . . . . . . . . . . . . 13 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 10. Informative References . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 T. Hao, et al. Expires November 13, 2015 [Page 2] Internet-Draft Hard IP Pipes May 2015 1. Introduction IP leased line services, Ethernet Private Line (EPL) and Time Division Multiplex (TDM) leased line services are commonly offered by operators worldwide. There are customers, e.g. many enterprises, which insist on TDM leased line services. They do so regardless of the fact that the same operators often offer IP leased line services, and EPL services, at a lower price and with a guaranteed bandwidth. Today we see a trend that the TDM (in particular SDH/SONET) networks gradually carries less and less traffic, and many operators want to shut their TDM networks down to save cost. The vendors and operators that build and deploy the Hard Pipe service described in this document do so recognizing the trends outlined above. A way to introduce leased line service with the same characteristics as TDM leased line services in IP/MPLS networks was created. Even if Leased Line has been the initially motivation to define the Hard pipe technology, the Hard Pipe is by no means limited to support Leased Line services. When guaranteed bandwidth is the priority Virtual Private Wire Services (VPWS), Virtual Private LAN Services (VPLS) L3 Virtual Private Networks (L3VPN) and IP only Private LAN Services can be mapped to a tunnel in the Hard Pipe stratum. EPL and EPLAN (Ethernet Private LAN) are out of scope for this document. The Virtual Leased Line (VLL) service is used for the examples throughout this document. The solution soon to be deployed has an Ethernet infrastructure, which has been split into two parallel logical networks - two parallel strata. The first stratum - the Hard Pipe stratum - does not use statistical multiplexing, and bandwidth is guaranteed end to end. The second stratum - Normal IP/MPLS stratum - works as a normal IP/MPLS network. The two strata share the same physical network, i.e. routers and links. But the resource reserved for the Hard Pipe stratum will never be preempted by the Normal IP/MPLS stratum. The routers will handle the traffic belonging to one stratum different from how traffic the other stratum is handled. This separation in traffic handling is based on support in hardware. T. Hao, et al. Expires November 13, 2015 [Page 3] Internet-Draft Hard IP Pipes May 2015 The reader of this document is assumed to be familiar with RFC 3031 [RFC3031] and RFC 5921 [RFC5921]. 1.1. Scope This document has the following purposes: o To introduce a two strata MPLS/IP network, the purpose of one of the strata is to provide capabilities for services that are from a customer's point of view functionally identical to TDM like leased lines. o To indicate how a router differentiates the traffic of the two strata. 1.2. Abbreviations CC, Continuity Check CV, Connection Verification L-label, Leased Line label LSP, Label Switched Path LSR, Label Switching Router MPLS-TP, MPLS Transport Profile NMS, Network Management System OAM, Operation, Administration and Maintenance P, Provider Router PE, Provider Edge Router PW, Pseudowire T-label, Tunnel label TDM, Time Division Multiplexing tLDP, Targeted LDP VLL, Virtual Leased Line VPLS, Virtual Private LAN Service T. Hao, et al. Expires November 13, 2015 [Page 4] Internet-Draft Hard IP Pipes May 2015 VPWS, Virtual Private Wire Service 2. The strata network The concept of stratified or strata networks has been around for some time. It appears to have different meaning in different contexts. The way we use the concept is that we logically assign certain characteristics to part of the network. The part of the network that has the special characteristics form one stratum and the "remainder " a second stratum. The network described in this document uses a single link layer technology, Ethernet. In many cases, a whole physical interface is assigned to a single hard stratum. Especially in the scenario that there are many physical links between two nodes. This document does not address the network configuration possibilities for Hard Pipe and IP/MPLS strata in detail. There are configuration options, the basic configuration is that one Hard Pipe stratum and one IP/MPLS stratum are provisioned. However it is also possible to provision more than one Hard Pipe stratum, e.g. if customers want enhanced separation for their leased line. Even though the main driver for the Hard Pipe technology is the leased lines, any service for which an operator does not want to use statistical multiplexing will benefit from using the Hard Pipes. 2.1. The Physical Network Consider a network with 10 routers and all the links between are 10G Ethernet, such as shown in Figure 1. This is the network topology we've used for this model, and also (with topology variations) in our first deployment. T. Hao, et al. Expires November 13, 2015 [Page 5] Internet-Draft Hard IP Pipes May 2015 +---+ 10G +---+ 10G +---+ 10G +---+ +---| B |-----------| C |-----------| D |----------| E |---+ 10G | +---+ +---+ +---+ +---+ | 10G | | | | | | +---+ | 10G 10G | 10G | 10G | +---+ --| F | | | | | | G |-- +---+ | | | | +---+ | | | | | | 10G | +---+ +---+ +---+ +---+ | 10G +---| H |-----------| J |-----------| K |----------| L |---+ +---+ 10G +---+ 10G +---+ 10G +---+ Figure 1 In this document we use the term traffic matrix or estimated traffic matrix to indicate an estimate of how much traffic that will flow between the ingress and egress (PE) nodes. This may be translated into how much bandwidth is needed per link in the Hard Pipe stratum. 2.2. The Hard Pipe stratum When the intention is to define a Hard Pipe stratum, it is for example possible to start from an estimated traffic matrix to estimate how much bandwidth to reserve on the links of the Ethernet Link Layer network for the Hard Pipes. Note that the implication is that the normal traffic gets the remainder of the available bandwidth. Thus the link layer network will be split into two logical networks, or two strata. One stratum to be used for the hardened pipe network, the other for the "normal" IP and MPLS traffic. This is shown in Figure 2 and Figure 3. T. Hao, et al. Expires November 13, 2015 [Page 6] Internet-Draft Hard IP Pipes May 2015 The Hard Pipe Stratum: +---+ 2G +---+ +---+ +---| B |-----------| C | | E |---+ 1G | +---+ +---+ +---+ | 2G | | | | +---+ 2G | 1G | +---+ --| F | | | | G |-- +---+ | | +---+ | | | | 1G | +---+ +---+ +---+ +---+ | 2G +---| H |-----------| J |-----------| K |----------| L |---+ +---+ 2G +---+ 4G +---+ 4G +---+ Figure 2 It is worth noting that even if the figures in this document are drawn to indicate "bandwidth on the link", the only bandwidth information that the nodes have available is the bandwidth assigned to the Hard Pipe stratum and the Normal IP/MPLS stratum. All other information is kept on the NMS. The NMS keeps a global bandwidth resource table for the Hard Pipe stratum. 2.3. The Normal IP/MPLS stratum Given that the starting point is the physical network in Figure 1 and the Hard Pipe stratum as defined in in Figure 2, the Normal IP/MPLS stratum will look as in Figure 3: T. Hao, et al. Expires November 13, 2015 [Page 7] Internet-Draft Hard IP Pipes May 2015 The Normal IP/MPLS Stratum: +---+ 8G +---+ 10G +---+ 10G +---+ +---| B |-----------| C |-----------| D |----------| E |---+ 9G | +---+ +---+ +---+ +---+ | 8G | | | | | | +---+ | 10G 8G | 10G | 9G | +---+ --| F | | | | | | G |-- +---+ | | | | +---+ | | | | | | 9G | +---+ +---+ +---+ +---+ | 9G +---| H |-----------| J |-----------| K |----------| L |---+ +---+ 8G +---+ 6G +---+ 6G +---+ Figure 3 2.4. Stratum Networks Stratum networks the way we use the concept can be seen as two basically parallel logical networks with strictly separated resources. Traffic sent over one stratum network can not infringe on traffic in the other stratum network. In the case described here, all the traffic in the Hard Pipe stratum is MPLS-encapsulated. A number of the labels have been set aside so other applications can't allocate them and so the routers recognize them as belonging to the Hard Pipe application. 3. Configuring the Leased Lines in Hard Pipe Stratum When the strata are provisioned the IP/MPLS stratum is set up exactly as any other IP/MPLS network. The one small difference between provisioning the Hard Pipe stratum and the IP/MPLS stratum is that no overbooking is done for the Hard Pipe stratum. Overbooking and/or congestion in the IP/MPLS stratum can not effect the Hard Pipe stratum. All labels used for the Hard Pipe stratum are "Configured Labels", i.e. labels that are provisioned and reclaimed by management actions. These management actions can be by manual actions or by an NMS or a centralized controller. For the size of network being deployed manual configuration is not practical, we are doing both provisioning and reclaiming a labels from an NMS. T. Hao, et al. Expires November 13, 2015 [Page 8] Internet-Draft Hard IP Pipes May 2015 o If an operator want to set up a leased line it is first checked if there is a path available in the Hard Pipe stratum that matches the criteria (e.g. bandwidth) for the requested leased line. * if such a path does exist, it is checked if there is a matching MPLS tunnel available over that path. + if such a tunnel exists, it is used to establish the leased line by adding L-labels forming an LSP that are carried by the tunnel. L-labels are known only by the ingress and egress LSRs. They are local to the end points the same way as the label signalled by Targeted LDP (tLDP) [RFC5036] are local the end points of a targeted session LSP. At the same time the available bandwidth in the Hard Pipe stratum is decremented by the bandwidth that is needed for the leased line for every hop across this stratum in the global resource table (for the Hard Pipe stratum). + if such a tunnel does not exist, it can be established so that the leased line can be set up as above. * If the path does not exist (not enough bandwidth in Hard Pipe stratum for the leased line), available bandwidth on the links is checked to see if the stratum can be expanded to accommodate such a path. + If the Hard Pipe stratum can be expanded, this is done and the tunnel for the leased line is established as described above. It is likely that other modifications of the Hard Pipe stratum, e.g. consolidating already set up Hard IP tunnels on to existing links so that room for new Leased Lines are created may have implication that goes well outside the Leased Line service, and it is currently not viewed as a fully automated operation. + If it is not possible to expand the Hard Pipe stratum to accommodate the new path, set up of the leased line will need to be declined. Thus, given the existence of a viable Hard Pipe stratum, Leased Lines are configured in two very simple steps. First, establish a hop-by- hop tunnel (T-labels), and second configure the leased lines T. Hao, et al. Expires November 13, 2015 [Page 9] Internet-Draft Hard IP Pipes May 2015 (L-labels). The T-labels need to be configured on both PE and P routers, while L-Labels only need to be configured on the PE routers. Note that L labels may be used for normal IP service [RFC3031], BGP/ MPLS VPNs [RFC4364] or PWs [RFC3985]. 4. Efficient State Management The system as described here generates a very small amount of state, and most of it is kept in the NMS. 4.1. State in the Forwarding Plane The only configured information that is actually kept on the LSRs is o the information needed for the label swapping procedures, i.e. incoming label to outgoing label and port, and whether the label belongs to the set of labels that are set aside for the Hard Pipe stratum tunnels. o the bandwidth available for the Hard Pipe stratum and the Normal IP/MPLS stratum 4.2. State in the NMS The following state needs to be kept in the NMS o the topology and bandwidth resources available in the Hard Pipe network, see Figure 2. o the total and available bandwidth per link in the Hard Pipe network see Figure 4. o the tunnel label mappings (T-labels) see Figure 5. o the Leased Line label mappings (L-labels) see Figure 6. o the reserved bandwidth, as well as other constraints and the path per Leased Line (L-labels) 4.3. Annotations for Configuring Leased Lines The annotations given below are neither a programming guideline nor an indication how this architecture could be implemented. It is rather an indication of how much data needs to be saved for each stratum and leased line, as well as where this data could be stored. T. Hao, et al. Expires November 13, 2015 [Page 10] Internet-Draft Hard IP Pipes May 2015 Considering the Hard Pipe stratum as it has been outline in Figure 2, there is actually some additional information related to the Hard Pipe Stratum that not is shown in the figure. Looking explicitly on the link between LSR J and K we find: +---+ +---+ +---+ +---+ ---| H |-----------| J |-----------| K |----------| L |--- +---+ +---+ +---+ +---+ [4,0]G Figure 4 The annotation [4,0]G means that 4G is allocated to the stratum on the link between J and K, and of these 0G has been allocated to a service. If we were to allocate two tunnels labels from the labels that has been configured to work within the Hard Pipe stratum the resource view would look like this: +---+ +---+ +---+ +---+ ---| H |-----------| J |-----------| K |----------| L |--- +---+ +---+ +---+ +---+ [4,0]G T1 ,T2 Figure 5 Note that allocating the tunnel labels does not reserve bandwidth for the tunnel from the Hard Pipe stratum. When the leased line labels (L-labels) are assigned, this will consume bandwidth. So we need to keep track of the bandwidth per leased line and the total of bandwidth allocated from the Hard Pipe stratum. The annotation for the link between J and K could look like this: T. Hao, et al. Expires November 13, 2015 [Page 11] Internet-Draft Hard IP Pipes May 2015 +---+ +---+ +---+ +---+ ---| H |-----------| J |-----------| K |----------| L |--- +---+ +---+ +---+ +---+ [4,1.5]G, T1, L1 [.5], L2 [.5], T2, L1 [.5] Figure 6 The line [4,1.5]G, T1, L1 [.5], L2 [.5], T2, L1 [.5] would be interpreted as: The Hard Pipe Stratum link between nodes J and K has 4 G bandwidth allocated; of the total bandwidth 1.5 G is allocated for Leased Lines. Tunnel label T1, carries two Leased Lines, each of 0.5G and tunnel label T2 carries a third Leased Line of 0.5G. Note that it is not necessary to keep this information in the nodes, it is held within the NMS, it is also strictly not necessary to keep the bandwidth per leased line, but some operations are simplified (e.g. removing a leased line) if this is done. 5. Setting Up Leased Lines Consider that the case where an operator want to set up a Leased Line of 0.4G from F to G in the Hard Pipe stratum in Figure 2. Since there are no other constraints than bandwidth and ingress and egress PEs, the shortest path will be chosen. A tunnel will be configure from F to G over the following nodes. F, H, J, K, L and G, and a Leased Line label (a) will be configured on F and G, and the available resources recalculated. A second leased line of 0.3G between the same PEs is easily configure by adding a new Leased Line label (b) at the ingress and egress PEs. After these operations a view of the Hard Pipe stratum resources (available bandwidth) would look like this: T. Hao, et al. Expires November 13, 2015 [Page 12] Internet-Draft Hard IP Pipes May 2015 The Hard Pipe Stratum: +---+ 2G +---+ +---+ +---| B |-----------| C | | E |---+ 1G | +---+ +---+ +---+ | 2G | | | | +---+ 2G | 1G | +---+ --| F | | | | G |-- +---+ | | +---+ | | | | .3G | +---+ +---+ +---+ +---+ | 1.3G +---| H |-----------| J |-----------| K |----------| L |---+ +---+ 1.3G +---+ 3.3G +---+ 3.3G +---+ Figure 7 If the operator now wishes to establish a new leased line with the criteria that it should originate from F and terminate at G, have 0.4G bandwidth and pass through node E, analysis of the Hard Pipe stratum (after establishing the first two listed lines) and the criteria for the new leased line would give the following; o the existing tunnel cannot be used, since it does not pass through E; a new tunnel need to be established. o the hop from F to H cannot be used since the available bandwidth is insufficient. o since no existing meet the criteria requested, a new tunnel will be set up from F, to B, C, J, K, L, E (the criteria to pass through E) and to G. A new L-label (c) to be carried over T2 will be configured on F and G, and the available resources of the Hard Pipe stratum will be recalculated. 6. Leased Line protection This leased line service uses the MPLS Transport Profile (MPLS-TP) line protection as it is defined in RFC 6378 [RFC6378], updated as specified in RFC 7271 [RFC7271] and RFC 7324 [RFC7324] The Connection Verification (CV) and Continuity Check (CC) are run over the tunnels between the Maintenance Entity Group End Points (MEP) at each end, i.e. the entire tunnel is protected end to end. T. Hao, et al. Expires November 13, 2015 [Page 13] Internet-Draft Hard IP Pipes May 2015 In general all of the MPLS-TP Operation, Administration and Maintenance (OAM), as defined in RFC 6371 [RFC6371] is applicable. 7. Security Considerations The security considerations as defined in RFC 5920 "Security Framework for MPLS and GMPLS Networks" [RFC5920] and RFC RFC 6941 "MPLS Transport Profile (MPLS-TP) Security Framework" [RFC6941] apply to this document. 8. IANA Considerations There are no requests for IANA actions in this document. Note to the RFC Editor, this section may be removed before publication. 9. Acknowledgements The authors want to thank Andy Malis for detailed technical and language review and for valuable comments. 10. Informative References [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, January 2001. [RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to- Edge (PWE3) Architecture", RFC 3985, March 2005. [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 4364, February 2006. [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP Specification", RFC 5036, October 2007. [RFC5920] Fang, L., "Security Framework for MPLS and GMPLS Networks", RFC 5920, July 2010. [RFC5921] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, "A Framework for MPLS in Transport Networks", RFC 5921, July 2010. [RFC6371] Busi, I. and D. Allan, "Operations, Administration, and Maintenance Framework for MPLS-Based Transport Networks", RFC 6371, September 2011. T. Hao, et al. Expires November 13, 2015 [Page 14] Internet-Draft Hard IP Pipes May 2015 [RFC6378] Weingarten, Y., Bryant, S., Osborne, E., Sprecher, N., and A. Fulignoli, "MPLS Transport Profile (MPLS-TP) Linear Protection", RFC 6378, October 2011. [RFC6941] Fang, L., Niven-Jenkins, B., Mansfield, S., and R. Graveman, "MPLS Transport Profile (MPLS-TP) Security Framework", RFC 6941, April 2013. [RFC7271] Ryoo, J., Gray, E., van Helvoort, H., D'Alessandro, A., Cheung, T., and E. Osborne, "MPLS Transport Profile (MPLS- TP) Linear Protection to Match the Operational Expectations of Synchronous Digital Hierarchy, Optical Transport Network, and Ethernet Transport Network Operators", RFC 7271, June 2014. [RFC7324] Osborne, E., "Updates to MPLS Transport Profile Linear Protection", RFC 7324, July 2014. Authors' Addresses JiangTao Hao Huawei Technologies Co., Ltd Q13 Huawei Campus No. 156 Beiqing Road Hai-dian District Beijing 100095 China Email: haojiangtao@huawei.com Praveen Maheshwari Bharti Airtel Ltd. Plot No. 16, Udyog Bihar, Phase IV, Gurgaon - 122015 Haryana India Email: Praveen.Maheshwari@in.airtel.com T. Hao, et al. Expires November 13, 2015 [Page 15] Internet-Draft Hard IP Pipes May 2015 River Huang Huawei Technologies Co., Ltd Q13 Huawei Campus No. 156 Beiqing Road Hai-dian District Beijing 100095 China Email: river.huang@huawei.com Loa Andersson Huawei Technologies Co., Ltd Stockholm Sweden Email: loa@mail01.huawei.com Mach Chen Huawei Technologies Co., Ltd Q13 Huawei Campus No. 156 Beiqing Road Hai-dian District Beijing 100095 China Email: mach.chen@huawei.com T. Hao, et al. Expires November 13, 2015 [Page 16]