Everything you need to know about mpls (mult protocol label ...Document Transcript
Everything You Need to Know About MPLS (Mult Protocol Label...The trend for network solutions encompassing multiple geographic locations is application ofMPLS solutions. And with very good reason. However, there are some things you need to know tomake sure its done right. Historically, tag switching (now called LABEL) was first proposed as a way to move IP packets more quickly than was possible with conventional routing. But, soon after implementations, it became apparent that any increase in speed was very slight. What really allowed MPLS to grow as an infrastructure technology was that it could provide new IP based services such as VPNs, Traffic Engineering (TE) etc.The MPLS architecture separates the control information for packets required for packet transferitself; that is, it separates the control and data planes. The data plane is used for the transport ofpackets (or label swapping algorithm), and the control plane is analogous to routing information(for example, the location to which to send the packet). This capability is programmed intohardware by the control plane. This separation permits applications to be developed anddeployed in a scalable and flexible manner. Examples of applications that are facilitated by MPLStechnology include the following......CLICK HERE TO GET INSTANT ACCESS TO CIRCUIT PROTOCOLSDownload this document if link is not clickableMPLS QoS, BGP VPNs Border Gateway Protocol (BGP), Traffic engineering Traffic engineering(enables one to control traffic routing via constraint-based routing), Multicast routing ProtocolIndependent Multicast (PIM), Pseudowires [These can be used to evolve legacy networks andservices, such as Frame Relay, ATM, PPP, High-Level Data Link Control (HDLC), and Ethernet],Generalized MPLS (GMPLS) etc.Services offered by Service Providers (SPs) may include the following.....* Layer 2 VPNs* Layer 3 VPNs
* Remote Access and IPSec Integration with MPLS VPNs* MPLS Security* Traffic Engineering* Quality of Service* Multicast and NGNs (Next Generation Networks)* IPv6 over MPLSMPLS models adopted by service providers (SP) of broadband services depend on the servicesoffered and also on the models adopted according to customer demands. The services providedhave changed significantly through the last few years as technology has progressed. For example,many wholesale providers who offered ATM as access links now have moved on to GigabitEthernet.For example, two of the most common braodband SPs would be the following.....* Retail Provider - Any provider thats sells services to an end-user which can be business orresidential. Usually they would lease bandwidth from a wholesale provider.* Wholesale Povider - Any operator that sells services to other network operators. In context ofthe current broadband world, the wholesaler is usually whoever owns the subscriber plant (wires,cables etc.)In between the subscriber and their "ISP" is the wholesale provider who owns actually owns andoperates the access network, for e.g, DSL, Cable, Ethernet etc. Of course, for an IP network, theseare just different types of access.Several applications that are facilitated by the implementation of MPLS include....* MPLS QoS - Quality of service mechanisms, for e.g, differentiated service, which enables thecreation of LSPs with guaranteed bandwidth.* Layer 3 VPN - Uses BGP in the service providers network with IP routing protocols or staticrouting between the service provider and the customer. BGP is used to exchange the FEC-labelbinding.* Traffic engineering - Uses extensions of IS-IS or OSPF to distribute attributes in the network.
Traffic engineering enables you to control traffic routing and thus optimize network utilization.* Multicast routing via PIM - The protocol used to create FEC tables; extensions of version 2 of thePIM protocol are used to exchange FEC label binding.* Layer 2 VPN - Can be created via a Layer 2 circuit over MPLS. Layer 2 VPNs use Layer 2transport as a building block.Of course, features such as Security and Metro Ethernet are part of the MPLS architecture also.Architectural Components and choices for SPs.......* Scaling MPLS VPNs to Multi-AS, Multi-Provider, and Hierarchical Networks:* Inter-AS VPNs: The 3 basic models discussed in RFC2547bis for Inter-AS connectivity are asfollows:- Back-to-back VPN connectivity between ASBRs- VPNv4 exchange of routes and peering between ASBRs- IPv4 exchange of routes and peering between ASBRsAll three above models focus on propagating VPN routes from one AS to the other AS. The firstmodel is a simple one in which the ASBRs connect back to back via logical circuits or VLANs oneper VRF. The back-to-back connections enable VPN connectivity and the exchange of routesbetween ASBRs on a per-VPN basis. For example, if ASBR1 and 2 need to exchange routes for 10VPNs, 10 logical circuits exist between ASBR1 and ASBR2one for each VPN.* Carrier Supporting Carrier.....Another method of scaling MPLS VPNs is to create hierarchical VPNs. Consider a national orinternational carrier that is selling a VPN service to smaller stub carriers. The smaller stub carriersmight in turn be selling another MPLS VPN service to end users (enterprises). By nesting stubcarrier VPNs within the core or national carrier VPN, a hierarchical VPN can be built. With the CSCmode described in RFC 2547bis, the stub carrier VPNs and their routes do not show up in the corecarrieronly the stub carrier IGP routes are part of the core carrier VPN. So, the core carrier doesnot need to learn or understand end user routes because the end user of the core carrier is thestub carrier. The core carrier needs only to provide VPN connectivity so that the core carriers CEs(ironically, they are stub carrier PEs) are reachable. These CEs are called CSCCEs, whereas the PEthat connects to the stub carrier and has MPLS enabled on the PE-CE link is called the CSCPE.
* Deployment Guideline considerations will involve the following summary guideline.....Centralizing address translation makes keeping track of address assignment easier. Multiple NATPEs might be required for load balancing. If this is the case, make sure public address pools donot overlap. One of the possible disadvantages to centralizing is the amount of redundancy thatcan be achieved by replication. For example, in a noncentralized environment, onegateway/server failure can result in an outage of only that VPNs service. However, in acentralized environment, a single gateway/shared PE failure can affect multiple VPNs. Thisdrawback can be easily overcome by having multiple PEs that serve as shared gateways, whichprovide services to the same VPNs. So, you can provide redundancy with shared gateways.If VPNs that use overlapping private address space need to access a shared services segment,make sure that private address space is translated somewhere in the path.NAT impacts CPU utilization to a degree. Some protocols are more CPU-intensive than others.Therefore, the type of translation being performed could have significant performance impact.The impact is less for newer particle-based routers and more powerful routers.As the number of translation entries increases, the throughput in terms of packets per second(PPS) decreases. The effect is negligible for less than 10,000 translation table entries.The rate at which a router can add a new translation table entry decreases as the number ofentries in the translation table increases.As the number of translation entries in the translation table increases, the amount of memoryused increases.In addition to the above, there must be considerations regarding the following tools andpolicies.....* Management, Provisioning, and Troubleshooting* Equipment Scalability Versus Network ScalabilityFinally, the basic arichitecture and mode of service will probably depend on customer demandand SPs commitment to deliver the same.Here is a small list of some of the things that customers might want....* More service selections * Better quality * Ease of migration * Ease of deployment * Ease of
maintenance * Lower cost * Fewer hasslesService providers want all of the above, plus......* High-margin accounts * Rapid recovery * No loss of service * 99.99999% reliabilityEnterprises want.......* A simpler, easier network to manageEnterprise networks range in consistency from very stable to constantly changing. Companies ongrowth trends are building new facilities and acquiring other businesses. They want ease ofintermigration and implementation. Changes must be ably employed within their limitedmaintenance windows. Their data centers must run flawlessly.The above information ... if it hasnt made your eyes go crossed ... should give you everythingyou ever need to know about MPLS.But if you need more ...... as in help to reduce your time, effort, cost, and frustration in finding theright MPLS solution for your network application(s) ..... I recommend using the no cost assistanceavailable to you through FreedomFire Communications.CLICK HERE TO GET INSTANT ACCESS TO CIRCUIT PROTOCOLSDownload this document if link is not clickableArticle source = ezinearticles.com/?Everything-You-Need-to-Know-About-MPLS-(Mult-Protocol-Label-Switching)