Madhulika Bhandure, Gaurang Deshmukh, Prof. Varshapriya J N / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 4, Jul-Aug 2013, pp. 71-76 Comparative Analysis of Mpls and Non -Mpls Network

Madhulika Bhandure1, Gaurang Deshmukh2, Prof. Varshapriya J N3 1, 2, 3(Department of Computer Science and IT, VJTI, Mumbai-19

ABSTRACT A new standard for a new world of from on complex over to the next. Originally networking, MPLS is a forwarding mechanism MPLS created by a crew of engineers that were based on Tag Switching. MPLS is an innovative consumed with improving the quickness of routers approach in which forwarding decision is taken nevertheless from the time it has emerged as a based on labels. Label is created for every route classic in today's telecommunications. There have in routing table. Large operators have embraced been a multitude number of attempts at developing multiprotocol label switching, deploying it in many technologies with the identical goals, to date their backbone networks to enable a number of none have reached the position of success that we services and applications such as virtual private now see with MPLS. To this extent what benefits networks to just name one. This paper presents arise out of using MPLS you may wonder? Well an overview of the MPLS technology and firstly, they allow internet service providers the related IETF standards, and how it is faster and savvy to maintain rapidly growing internet. In better than traditional IP routing. addition allows for fundamental adjustability. Appreciating MPLS means looking to some of the Keywords - LDP, LSP, LSR, MPLS, QoS parts that exist concerning to the MPLS such as the label which is a locally significant identifier that is I. INTRODUCTION allotted to a packet. Every label contains four Early computer networks were circuit fields, a label value, traffic class field which switched networks where continuous bit streams determines the quality of service, bottom of stack carried over the physical links. This was well label which is not always set but when it is it suitable for voice and data unicast communications. signifies that the label is currently the last in the This leads to some severe consequences in case of stack and finally there is the "time to live" (also failure. All the communications over the failed link referred to as TTL) field which is the limit of time are interrupted in such situation. These days packet that data can experience before it will be discarded. switched networks are used in which data is To realize the magnitude of MPLS one just has too divided into small chunks called as a packet and measure it against some earlier technologies that these packets are routed over the communication are similar like the frame relay which focused on links. Different packets can take different paths .In making previously existing physical resources case of link failure , the packets can be rerouted more adequate. In recent days the use of frame lay through alternate available path to avoid failed link has been given a poor name in several markets and hence communication is not interrupted. This because of overdone bandwidth used by some feature makes packet switched networks more companies hence making the use of MPLS much reliable but on other hand as packets are routed more alluring. individually , it is difficult to manage flow of data. One more similarity would be that Traditional IP networks offer little predictability of between ATM (also referred to as Asynchronous service, which is undesirable for applications such Transfer Mode) MPLS when comparing the two as telephony, and for rising and future real-time have many differences both offer connection applications. IP networks are frequently layered oriented service to allow for transporting data over ATM networks, which is very expensive in across networks. An MPLS connection shows the terms of overhead (adding 25 percent or more of most significant difference in its approach as they overhead to every IP packet)[5], but had one great are able to work with various lengths of packets advantage, IP networks have no means of tagging where as an ATM is only capable of dealing with a or monitoring the packets that cross them. The fixed length. The most favorable difference you history tells us the upper limit of transmittable will find between the two is MPLS configuration bandwidth doubles and sometimes quadruples which was developed specifically for internet every nine to twelve months. We need matching protocol. MPLS are just being used only with data transferring topologies as well as improved internet protocol networks and are standard. It can system reliability. connect to two facilities or can control thousands of Multiprotocol Label Switching is a tool locations simultaneously. MPLS does not compete applied in distinguished performance with IP forwarding but it complements IP telecommunications networks that carries materials forwarding. MPLS technology works to solve those flaws of IP, encapsulating IP packets within labels.

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MPLS is not designed to replace IP; it is designed In MPLS technology, a specific path is set up for a to add a set of rules to IP so that traffic can be given sequence of data packets. These packets are classified, marked, and policed. MPLS identified by the packet label, thereby saving the (Multiprotocol label switching) as a traffic- time that a router takes to search the address where engineering tool has emerged as an elegant solution the packet should next be forwarded. MPLS is to meet the bandwidth management and service referred to as "multiprotocol" since it closely works requirements for next generation Internet Protocol with IP, ATM, and frame relay network protocols. (IP) based backbone networks [12].An MPLS[4] The major benefits of MPLS networks network can offer the quality of service guarantees include: that data transport service like frame relay (FR) or Traffic Engineering - The capacity to determine the ATM give, without requiring the use of any path that the traffic will take through the network dedicated lines. The availability of traffic MPLS VPN - Service providers can create IP engineering has helped MPLS reach critical mass tunnels all over their networks using MPLS, which in term of service provider mind share and does not necessitate encryption or end-user resulting MPLS deployments. Most carriers run applications MPLS underneath a wide range of services, Layer 2 services (ATM, Ethernet, frame relay) can including FR, wide-area Ethernet, native IP, and carried over the MPLS core Simplified network ATM. Advantages accrue primarily to the carriers. management through elimination of multiple layers User benefits include lower cost in most cases, MPLS has become popular due to its greater control over networks, and more detailed capability to form multi-service networks with high Quality of Services. speed. It can support pre-provisioned routes that This paper is organized as follows: are virtual circuits known as Label-Switched Paths Section 2 gives details about MPLS. Section 3 (LSPs), across the network. Provision for backing gives the comparative analysis of MPLS and non- up multiple service categories containing different MPLS network. Sections 4 introduce proposed forwarding and drop priorities, is also available topology for comparative analysis. Section 5 shows with this technology. Multiprotocol label switching the experimental results. Section 6 summarizes our addresses common networking problems such as work and concludes this paper. scalability, speed, Quality of Service (QoS), and traffic engineering, and provides them a viable and II. MULTIPROTOCOL LABEL effective solution. Owing to its versatility, MPLS SWITCHING has emerged as a solution capable of meeting Multiprotocol Label Switching (MPLS) is bandwidth and other service requirements for IP- a data-carrying mechanism, in computer based networks. Scalability and Routing - based networking and telecommunications , which is issues can be resolved by MPLS technology, which highly scalable and protocol agnostic. Often also has the capacity to exist over existing ATM referred to as "Layer 2.5 protocol" MPLS and Frame relay networks. Considering the positive technology operates between the points and shortcomings of ATM, MPLS (Layer 2) and the (Layer 2) of the technologies were designed to provide more OSI Model. MPLS is part of the family of packet- leverage to network engineers and to be deployed switched networks. It was designed primarily to flexibly. provide a unified data-carrying service for Circuit- The marketplace is constantly being based as well as Circuit-switching clients. Both the replaced with new technologies and technology clients offer a datagram service model. devices. MPLS came to the forefront when there Multiprotocol Label Switching enables to carry was a requirement for a protocol that needs less diverse types of traffic such as Asynchronous overhead and at the same time provides connection Transfer Mode (ATM), Internet Protocol (IP) oriented-services for frames of variable length. packets, Synchronous Optical Networking Technology such as ATM and frame relay has been (SONET), and Ethernet frames. Labels are replaced in many areas by MPLS technology, assigned to the data packets in an MPLS network. which combines many options to satisfy the Based on the label contents, packet-forwarding technology requirements of clientele. Specifically, decisions are made, without necessitating MPLS has dispensed cell-switching and signaling examination of the data packets. Through this protocol used by ATM. Concurrently, feature, end-to-end circuits may be created using Multiprotocol label switching technology continues any protocol over any type of transport medium. to maintain the traffic engineering and bandwidth MPLS technology is beneficial as it helps to control, which was popularized by ATM and frame eliminate the dependence on ATM, Frame relay, relay in large-scale networks. Migration to MPLS SONET, Ethernet, etc., which are Layer 2 technology is beneficial especially since the technologies. It also does not require multiple data benefits of traffic management are important. link layer networks to gratify different traffic types. Performance level increases and so does reliability.

72 | P a g e Madhulika Bhandure, Gaurang Deshmukh, Prof. Varshapriya J N / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 4, Jul-Aug 2013, pp. 71-76

Currently, MPLS is used in large "IP only" networks. It is mainly used for forwarding Ethernet traffic and IP datagrams. MPLS VPN (Virtual Private Network) and traffic engineering are the major application areas of MPLS technology. MPLS IP VPN, a layer 3 VPN technology, is used to check, classify, and monitor IP packets. It is based on the service provider, to secure overlay VPN solutions. MPLS IP VPN is distinguished for its flexibility in networking modes, and features such as network scalability, QoS, and traffic engineering. Today′s business operations employ diverse applications across the Wide Area Networks (WANs) and it is essential to Fig 1. Planes of router manage and prioritize traffic over the networks Label distribution protocol (LDP): It securely. This necessitates the use of technology communicates labels and their meaning among such as MPLS IP VPN, which is a proven method LSRs. It assigns labels in edge and core devices to for traffic engineering and network security. establish LSPs in conjunction with routing Here is some MPLS terminology: protocols such as Open Shortest Path First (OSPF), Label switch router (LSR): It refers to any Intermediate System to Intermediate System (1s- router that has awareness of MPLS labels. The IS), Routing Information Protocol (RIP), Enhanced entry and exit routers of an MPLS network are Interior Gateway Routing Protocol (EIGRP), or called edge LSR (or label edge routers – LER), Border Gateway Protocol (BGP). which, respectively, inject (push) an MPLS label onto an incoming packet (label assignment) and III. COMPARATIVE ANALYSIS OF remove (pop) it off the outgoing packet (label MPLS AND NON -MPLS removal). An edge LSR is often a high-speed router NETWORK device in the core of an MPLS network that 3.1 TRADITIONAL IP ROUTING participates in the establishment of Label Switched In traditional IP routing, each router in the Paths (LSP) using the appropriate label signaling network has to make independent routing decisions protocol and high-speed switching of the data for each incoming packet. When a packet arrives at traffic based on the established paths. a router, the packet is stored in data plane of router. Label switched path (LSP): It is path Each port of router is in its data plane. Now first defined by labels assigned between end points. An layer 2 processing will be done on packet to check LSP can be dynamic or static. Dynamic LSPs are whether the packet is destined for that particular provisioned MAC of router. If yes then now layer 3 processing automatically using routing information. Static of packet is performed. Layer3 process will check LSPs are explicitly provisioned. routing table, which is in control plane, the router Label (LVC): It is a hop-by-hop to find the next hop for that packet based on the connection established at the ATM transport layer packets destination address in the packets IP header to implement an LSP. (longest match prefix lookup). Each router runs IP LFIB: Used by the core MPLS routers (which are routing protocols like Border Gateway Protocol not ingress and egress MPLS routers). They (BGP), Open Shortest Path First (OSPF) or compare the label in the incoming packet with the Intermediate System-to-Intermediate System (IS- label they have in their LFIB. If a match is found, IS) to build the routing table. Now if next hop is the routers forward that packet based on that match. available then again layer 2 processing will be done If not, the packet will be dropped. to change the destination MAC of the packet and then the packet is forwarded to required port. Now routing table, layer 2 and processes are present in control plane of router. Each time for each packet which in data plane, each router performs the same steps of finding the next hop for the packet. The main issue with conventional routing protocols is that for entire decision making process, there will be transfer of processing from control plan to data plan many times. So this is time consuming process. Also IP routing is performed at each hop of the packets path in the network. Entire IP header analysis is done at each hop which is time

73 | P a g e Madhulika Bhandure, Gaurang Deshmukh, Prof. Varshapriya J N / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 4, Jul-Aug 2013, pp. 71-76 consuming. Additionally there is problem if traffic always performs lookups on fixed-length values is of different type. Now for multicast traffic , and with equality operation, not with prefix-based router maintains routing multicast table. IP routing logic. Hence, at least in theory, a routing table requires special multicast routing and forwarding lookup is algorithmically more complex than a algorithms. These are the three main reasons lookup in the LFIB, as finding a longest prefix because of which the traditional IP routing is match is more computationally intensive than slower. MPLS overcomes all these three drawbacks simply finding a single matching value. Therefore of IP routing. the LFIB lookups should be faster. MPLS forwards packets based on the 3.2 MPLS TECHNOLOGY MPLS labels, instead of using the packet’s Multiprotocol label switching (MPLS) is destination IP address. an addition to the existing Internet Protocol (IP) Advantage of using labels and not the destination architecture. By adding new capabilities to the IP IP address is that packet forwarding decision can architecture, MPLS enables support of new features be made on the other factors such as traffic and applications. In MPLS short fixed-length labels engineering and QoS requirements. In MPLS the are assigned to packets at the edge of the MPLS first device does a routing lookup, just like in domain and these pre assigned labels are used traditional IP routing. But instead of finding a next- rather than the original packet headers to forward hop, it finds the final destination router. And it packets on pre-routed paths through the MPLS finds a pre-determined path from current router to network [12]. In MPLS, the route the packet is that final router. The router applies a “label” (or forwarded through the MPLS domain is assigned “shim”) based on this information. Future routers only once i.e., when the packet enters the domain. use the label to route the traffic without needing to Before a router forwards a packet it changes the perform any additional IP lookups. At the final label in the packet to a label that is used for destination router, the label is removed and the forwarding by the next router in the path. packet is delivered via normal IP routing. MPLS unicast IP forwarding logic Therefore in an MPLS network, data packets are forwards packets based on the labels, however assigned labels. Packet-forwarding decisions are when choosing the exit interfaces, MPLS considers made solely on the contents of this label, without only the routes in the unicast IP routing table. This the need to examine the packet itself.FEC is results in the packet flows over the same path as it forward equivalence class which means providing would have even if MPLS was not used. Using the type of behavior to reach the destination. MPLS labels does not add any benefit by itself, but Whatever is the type of traffic (unicast or it essentially enables the MPLS traffic engineering multicast), the mechanism used and forwarding in an MPLS network, and therefore a critical algorithm used to take decision is same. Hence feature of the MPLS.MPLS still requires the use of MPLS is faster. control plane protocols such as OSPF and LDP to learn the labels and relate those labels to particular IV. PROPOSED METHODOLOGY destination prefixes for building correct forwarding The simulation environment employed in tables. MPLS also requires a fundamental change this paper is based on GNS 3.0 simulator. The to the data plane’s core forwarding logic, it defines simulations were setup using a normal IP network a completely different packet-forwarding logic. In without Traffic engineering (composed of OSPF an MPLS network, the hosts should not send and and BGP) and a MPLS network (composed of receive labeled packets. All labeled packets are OSPF and BGP) are implemented. The results from only for the routing and only routers should be these simulations are used for comparison between sending and receiving the labeled packets in an the two networks. Both simulations are based on MPLS network. Here when packet arrives at a the common topology as shown in Fig 2 . router, it is stored in data plane. Now to take forwarding decision , router refers the LFIB table which in data plane itself. Now decision will be done on basis of LFIB and taken in data plane only. Labeled packet is switched to required port and as it does not involve processing of control plane , the process is faster. The principal difference between a lookup in the routing table and the MPLS LFIB is that the routing table lookup is concerned with longest prefix match, i.e. having potentially many (imprecise) matches and selecting the one that most closely resembles the destination IP address. On the other hand, the MPLS LFIB

74 | P a g e Madhulika Bhandure, Gaurang Deshmukh, Prof. Varshapriya J N / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 4, Jul-Aug 2013, pp. 71-76

IP(non mpls MPLS network) Number of 335 332 packets received Average 0.769 4.728 packets per sec Average 83.313 98.705 packet size Bytes 27910 32770 transferred Average bytes 64.061 466.703 per sec Average 0.001 0.004 megabits per sec In Table 1. we can see that, though size of packet in MPLS is bigger than in IP because of additional label, average packets per sec in MPLS is three- four times more than that in traditional IP routing. Fig 2. Experimental topology Also average megabits per sec is more in MPLS domain. Hence we can say MPLS is faster than The network consists of 9 nodes. Out of traditional IP routing. Using GNS3 for bandwidth which, 5 nodes are service provider nodes. So to testing might not be the best idea, as bandwidth in compare performance of service provider networks GNS3 is very limited because IOS is emulated, , we will initially use only these 5 nodes. All links which is very slow. We can usually expect a few were setup as duplex. The MPLS Traffic KB/s only depending how fast is our computer. In Engineering simulation topology is similar to the IP fact here all the results were obtain through a topology with only difference being that all nodes simulator software and will differ from results on are MPLS capable, which allow label switching. actual hardware. But we can compare both The work is simulated using a network networks using this simulator. with following characteristics.  Service provider network with 4 provider edge VI. CONCLUSION router(PE1-PE4) and one core router(P) MPLS is a technology that is extremely Delhi site beneficial to enterprises. MPLS simplifies the Mumbai site network infrastructure by allowing the Bangalore site consolidation of multiple technologies and Kolkata site applications such as voice, video and data. MPLS  All type of traffic provides enhanced security, scalability and high  Without QoS availability. Via the above-mentioned theories  Traffic routed by LSP analysis and experiment simulation we can see, the  OSPF as IGP MPLS is faster than traditional routing technique. The output trace file from the simulation is used to If we can improve hardware facilities and software measure the performances of the network such as: platform by real routers then we can notice the Average packets per sec, average packet size, bytes significant differences. transferred, average bytes per sec, average megabits per sec etc. REFERENCES [1] A. Ghanwani. "Traffic Engineering V. SIMULATION RESULTS Standards in IP Networks Using MPLS" Now we can compare the differences IEEE Communications Magazine, vol. 37, between both scenarios. Both scenarios use OSPF no. 12, pp. 49- 53. Dec. 1999. as IGP. Also the core router is not connected to any [2] B. Jamoussi et al, “Constraint-Based LSP customer router, so there should not be any Setup using LDP” IETF RFC 3212, Jan. customer route present here. Due this fact, the 2002. routing table of P router will be precise and [3] D. Awduche et al, “RSVP-TE: Extensions concise. And this P router will do forwarding on to RSVP for LSP Tunnels” IETF RFC wired speed. BGP is used to form indirect 3209, Dec. 2001 neighbourship between edge routers. Table 1.Comparing IP and MPLS network

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[4] E. Rosen, A. Viswanathan and R. Callon, “Multiprotocol Label Switching Architecture,’’ RFC 3031, Jan. 2001. [5] IEEE Communication magazine, September – 2006. [6] J. L. Marzo, E. Calle, C. Scoglio, and T. Anjali, “QoS online outing and MPLS multilevel protection: a survey,” IEEE Communication Magazine, vol. 41, pp. 126-132, Oct. 2003. [7] J. M. Chung, E. Marroun, H. Sandhu, and S. C. Kim “VoIP over MPLS Networking Requirements,” Proceedings of IEEE International Conference on Networking,. France, July. 2001. [8] J. M. Chung, “Analysis of MPLS Traffic Engineering,” Proceedings of the IEEE Midwest Symposium on Circuits and Systems, USA, Aug. 2000. [9] J. Wroclawski, “The Use of RSVP with IETF Integrated Services” IETF RFC 2210, Sep. 1997. [10] L. Zhang et al, “Resource Reservation Protocol (RSVP)” IETF RFC 2205, Sep. 1997. [11] Muzammil Ahmad Khan. “Quantitative Analysis of MPLS in VPN's”, Sir Syed University of Engineering and Technology, from www.ieeexplorer.org. [12] UYLESS BLACK – MPLS and Label Switching Network.

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