Network Project - MPLS QoS

Link to my classmates' page http://www.msu.edu/~hsuhsuni/SVU/CS426TP.html
MPLS QoS Abstract Quality of Service (QoS) is an important feature of a network. It provides different levels of services to different types of data. This will help providers to divide the market into different parts. Business users pay more money, because their data may be business-critical and need certain level of quality. And QoS can provide them the quality they want. Most people, like you and me, are not really care about the quality of service. Multiprotocol Label Switching (MPLS) is a popular technology these years. I want to know the relationship between them. Moreover, we will learn more detail of MPLS and QoS. 1.What is MPLS? 1.1 Overview MPLS is a packet-forwarding technology. The labels help to make data forwarding decisions. The MPLS makes the implement of Virtual Private Network (VPN), Traffic Engineering (TE), Quality of Service (QoS) easier. It reduces the overheads on routers. Because the routers just have to read the labels. MPLS also works with ATM. The MPLS network is more efficient than IP routing. The LSRs don¡¦t have to read the IP headers. LSRs deliver the packets according to the labels. The packets are labeled only once. Once the packets arrived at a LER, the LER labeled the packets with label(s). The label(s) contain all information the LSRs need. Because the label is already there, LSRs can deliver the labels very fast without making routing decisions. 1.2 Basics in MPLS 1.2.1. LDP Label Distribution Protocol (LDP): There are several protocols can be used to distribute labels. Border Gateway Protocol (BGP) and Resource Reservation Protocol (RSVP) can be used as LDPs. There is also MPLS-LDP. It¡¦s designed for MPLS. 1.2.2. LER Label Edge Router (LER): There two kinds of routers in MPLS networks. LERs are connected with non-MPLS routers directly. 1.2.3. LSR Label Switch Router (LSR): There are two kinds of LSR. LSRs connect with other MPLS LSRs or LERs directly. Figure. An example of simple MPLS network 1.2.4. Forwarding Equivalence Class (FEC) 1.2.5. Label Switch Path (LSP) 1.2.6. Label : Each label is a fixed length (4 bytes) field. The labels are placed between layer 2 and layer 3 in Ethernet packet, in the VPI/VCI field of the header in ATM networks,and in the DLCI field of a frame relay header. Labels can be stacked. The top label appears near Layer 2 header and bottom label appear near Layer 3 header. Figure The Labels are imposed between Layer 2 and Layer 3 The label is divided into four parts. First 20 bits (Label) contain label value. 3 bits (Exp) are for experimental use. One bit (S) indicates Bottom of (label) Stack. Last 8bits (TTL) stand for Time To Live. 1.3 How MPLS is implemented When the packets come to MPLS domain, the LSR 1.41 Packet pass into MPLS domain, ER assigns FEC and use LDP to make Labels to this packet. 1.43 ER forward the packet to next MPLS hop 1.44 CR read the first label and removes the first label then forward to next MPLS hop 1.46 Finally, the last hop (ER) peel the last label and forward the packet leave MPLS domain. 1.4 Venders 1.41Hardware: AcceLight Networks, Avici Systems, Cisco Systems, CoSine Communications, Ericsson, Integral Access,Juniper Networks,Lucent (Ascend), Nortel Networks ,Riverstone Networks ,Unisphere Networks. 1.42 MPLS Code: Data Connection, Future Software, NetPlane, Trillium, Virata. There are also many companies and organizations provide sharewares and freewares. If you want to simulate MPLS, there are also lots of simulating tools. 1.5 Generalized MPLS (GMPLS) The generalized Multiprotocol Label Switching is also refers as multiprotocol lambda switching. The multilayer structures we current using have some problem. If any layer is inefficient, the entire network will be inefficient. Some people predict that the network structure will be much different. The bottleneck will be removed in these two years. ATM and SONET may disappear from the market. The network structure will have only IP/GMPLS and DWDM without ATM and SONET. The SONET and ATM were good enough in last 5 years. But we have more data flow which consume more capacity over the network. IP with GMPLS over DWDM may play more important role in the next generation network. Figure. The evolution to photonic networking 2.What is QoS? 2.1 Overview Quality of Service (QoS) is an important part to make money in the network. Without QoS, all data will be treated the same. This condition just like drive in highway 101 during rush hours without separating the traffic. Everyone wants to get home earlier but nobody can really get home earlier. QoS, like car pool, can separate different traffics and treat them different. In this case, if we have two or more people in the vehicle, we can drive in the carpool lane and get to the destination earlier. In really networks, there are many kinds of traffics. Without QoS, all packets are forwarded Best-Effort. With QoS, we can separate different traffics. Different traffics will be treated differently. For instance, Video and voice are treated different from file transferring. Service providers provide QoS to give customers better services. They can make more money by separate the market from one to several small ones. 2.2 How to Measure There are several parameters to measure the quality of service. (*1) 1. Service availability ¡V reliability of the user¡¦s connection to the Internet service. 2. Delay (latency) - refers to the interval between transmitting and receiving packets between two reference points. 3. Delay variation - refers to the variation in time duration between all packets in a stream taking the same route. 4. Throughput ¡Vthe rate at which packets are transmitted in a network; can be expressed as an average peak rate. 5. Packet loss rate-maximum rate at which packets can be discarded during transfer through a network; packet loss typically results from congestion. 2.3 Integrated Service (Int-Serv) Integrated Service (Int-Serv) was defined in RFC 1633. The Resource Reservation Protocol (RSVP) is also proposed in RFC 1633. This seems likely will be implemented at the edge of the network where users can manage at the desktop user level. 2.4 Differentiated Services(Diff-Serv) Differentiated Services (Diff-Serv) comes after the Int-Serv and also been discussed in many RFCs. The Differentiated Services use the type of service (ToS) field in IPv4 header and the Traffic Class field in IPv6. Both fields are 8 bits long. Diff-Serv also renames the 8-bits field as the Differentiated Services (DS) field, with 6-bits available for current use and 2-bits reserved for future use. Figure. Type of Service field in IPv4 Header Figure. Traffic Class field in IPv6 Header. Both these fields are 8-bits long and been divided into differentiated services codepoint (DSCP 6-bits) and currently unused (CU 2-bits) 0 1 2 3 4 5 6 7 DSCP CU Figure. ToS field and Traffic Class field 2.5 Per-hop Behavior (PHB) Per-hop Behavior (PHB) is a description of the externally observable forwarding treatment applied at a differentiated services-compliant node to a behavior aggregate. The description of a PHB SHOULD be sufficiently detailed to allow the construction of predictable services.(*RFC 2474) In another word, the PHB is a list which include detail instructions to forward different classes of packets. 2.6 Service Level Agreement (SLA) An SLA defines end-to-end service specifications and may consist of the following: Availability, Services offered, Service guarantees, Responsibilities, Auditing the service, Pricing. 2.7 Industry of QoS 2.71 Vendors Extreme Networks http://www.extremenetworks.com/ IPHighway(Closed) http://www.iphighway.com/ IPivot, Inc. Orchestream http://www.orchestream.com/ Packet Engines Qosnetics Redback Networks, Inc. http://www.redback.com/ Xedia Corporation These vendors make Network Management Software, Router Equipment, Switch Equipments. 2.72 Protocols Supported There are several protocols support different levels of QoS. But only 7 of them have practical products. List below: (*QoS Forum) 802.1D-1998 (9 products) 802.1Q (10 products) 802.1p (5 products) CBQ (2 products) DiffServ (2 products) MPLS (2 products) RSVP (11 products When I look browse the internet and looking for these vendors, I can only got part of them. One is closed and some websites can¡¦t be found. 3.Relationship between MPLS and QoS The QoS is a general idea. The ultimate goal of QoS is to separate the network flow and treat different services differently. MPLS is one way to implement the QoS. There are lots of protocols can do QoS. All protocols have strength and weakness. MPLS is popular in QoS because the features are more practical. It makes switches do the jobs what routers do. MPLS saves some investment for the current ATM equipment owners. ATM devices can function as LERs and LSRs. With FEC in MPLS, LERs and LSRs can treat packets in different FECs different. This achieves one of the objectives of QoS ¡V Priority. Different FECs can be seemed as different SLA. Packets in these FECs are treated different. Eventually, some packets get to destination very fast. Some never reach the destination. Some get to the destination but not very fast. Because those packets are not in the same FEC so they were treated different. 4.Conclusion MPLS is a good idea to increase network efficiency. The network efficiency can be measured in many aspects. We can improve the network traffic with FEC in MPLS. It¡¦s not easy to provide QoS in the Internet. This will involve different layers of the network. The scheme at the transport/network layer is Diffserv. The schemes at the network layer are traffic engineering and fast reroute. The application-layer schemes are traffic directing and load balancing.(*10) This report only talk about the MPLS which is involved in network layer and transport layer. Actually, MPLS is much popular than QoS. With MPLS, the network can be faster than before. Besides it¡¦s not only for service providers. A single company can apply MPLS to improve the network and get part of QoS. QoS is too general and any layers are involved. 5.Reference 1. ¡§IP QoS-A Bold New Network¡¨, http://www.nortelnetworks.com/solutions/collateral/qos_wp.pdf 2. K. Nichols, S. Blake, F. Baker, D. Black, ¡§Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers¡¨, RFC 2474, December 1998 3. E. Rosen, A. Viswanathan, R. Callon, ¡§Multiprotocol Label Switching Architecture¡¨, RFC3031, January 2001 4. David Passmore, "Clearing Up MPLS Confusion", http://www.bcr.com/bcrmag/2000/06/p18.asp, 2000 5. Ayan Banerjee, John Drake, Jonathan P. Lang, Brad Turner, Kireeti Kompella, Yakov Rekhter, ¡§Generalized Multiprotocol Label Switching: An Overview of Routing and Management Enhancements¡¨, http://www.calient.net/files/GMPLS.pdf 6. ¡§A Comparison of Multiprotocol Label Switching (MPLS) Traffic-Engineering Initiatives¡¨, http://www.iec.org/online/tutorials/mpls_traffic/index.html 7. ¡§Cisco IOS MPLS Quality of Service¡¨, http://www.cisco.com/warp/public/cc/pd/iosw/prodlit/mpios_wp.pdf 8. ¡§MPLS FAQ For Beginners¡¨, http://www.cisco.com/warp/public/105/mpls_faq_4649.shtml 9. Darrin S. Woods, ¡¨MPLS: A New Traffic Cop for Your WAN¡¨, July 10, 2000 http://www.networkcomputing.com/1113/1113ws2.html 10. Xipeng Xiao, ¡§PROVIDING QUALITY OF SERVICE IN THE INTERNET¡¨, http://www.cse.msu.edu/~xiaoxipe/papers/thesis/thesis.pdf 11. William Stallings, ¡§Data and Computer Communications¡¨, Sixth Edition, Prentice Hall International, Inc. 2000 12. ¡§White Paper - The Need for QoS¡¨, http://www.qosforum.com/white-papers/Need_for_QoS-v4.pdf 13. ¡§QoS FAQ¡¨, http://www.qosforum.com/docs/faq/ 14. ¡§White Paper - QoS protocols & architectures¡¨, http://www.qosforum.com/white-papers/qosprot_v3.pdf 15. Xipeng Xiao, Lionel M. Ni, ¡§Internet QoS: the Big Picture¡¨, http://www.cse.msu.edu/~xiaoxipe/papers/msu.inet.qos.bigpicture.pdf 16. Rick Gallaher, ¡§An Introduction to MPLS¡¨, September 10, 2001, http://www.convergedigest.com/Bandwidth/archive/010910TUTORIAL-rgallaher1.htm