Proekt Seti Metro Ethernet Diplom

A metropolitan-area Ethernet system A metropolitan-area Ethernet, Ethernet MAN, or metro Ethernet network is a (MAN) that is based on. It is commonly used to connect subscribers to a larger service network or the. Businesses can also use metropolitan-area to connect their own offices to each other. An Ethernet interface is much cheaper than a (SONET/SDH) or (PDH) interface of the same bandwidth. Another distinct advantage of an Ethernet-based access network is that it can be easily connected to the customer network, due to the prevalent use of Ethernet in corporate and, more recently, residential networks. A typical network is a collection of and connected through.

The could be a, (star), or full or partial. The network will also have a hierarchy: core, distribution (aggregation), and access. The core in most cases is an existing / backbone but may migrate to newer forms of Ethernet transport in the form of 10Gbit/s, speeds or even possibly 400Gbit/s to network in the future. Ethernet on the MAN can be used as pure Ethernet,, Ethernet over (MPLS), or Ethernet over. Pure Ethernet-based deployments are cheaper but less reliable and scalable and thus are usually limited to small scale or experimental deployments. SDH-based deployments are useful when there is an existing SDH infrastructure already in place, its main shortcoming being the loss of flexibility in bandwidth management due to the rigid hierarchy imposed by the SDH network.

MPLS-based deployments are costly but highly reliable and scalable and are typically used by large service providers. Contents • • • • • • • • Metropolitan area networks [ ] Familiar network domains are likely to exist regardless of the transport technology chosen to implement: Access, aggregation/distribution, and core. • Access devices normally exist at a customer's premises, unit, or wireless base station. This is the network that connects customer equipment, and may include (ONT), a residential gateway, or office router.

• Aggregation occurs on a distribution network such as an segment. Often, microwave or technologies are employed, but some of them using point-to-point Ethernet over 'home-run'. This part of the network includes nodes such as Multi Tenanted Unit switches, in an or cabinet, equipment, or provider bridges. • A MAN may include the transport technologies MPLS, and T-MPLS, each with its own resiliency and management techniques. • A core network often uses IP-MPLS to connect different MANs together. Much of the functionality of Ethernet MANs such as virtual private lines or is implemented by the use of Ethernet tags that allow differentiation of each part of the network.

Logical differentiation of the physical network helps to identify the rights that the traffic has and to ease the management of hosts' access rights with respect to other users and networks. MPLS-based Ethernet MANs [ ] A (MPLS) metro Ethernet network uses MPLS in the service provider's network.

Computer Networking and Technical Support (Diploma). ISDN, Metro Ethernet, DSL and SONET), fast packet services (X.25, Frame Relay and ATM), and Multiplexing.

The subscriber will get an Ethernet interface on copper (for example, ) or fiber (such as ). The customer's Ethernet packet is transported over MPLS and the service provider network uses Ethernet again as the underlying technology to transport MPLS. So, it is Ethernet over MPLS over Ethernet.

(LDP) signaling can be used as site to site signaling for the inner label (VC label) and Resource reSerVation Protocol-Traffic Engineering () or LDP may be used as Network signaling for the outer label. One restoration mechanism used in an MPLS based Metro Ethernet Networks is Fast ReRoute (FRR) to achieve sub-50ms convergence of. For each deployment situation the benefit versus cost of MPLS must be weighed carefully, so if not implemented on a carrier's distribution network there might be more benefit for MPLS the core network. In some situations the cost may not warrant the benefits, particularly if sub 50ms convergence time is already being achieved with pure Ethernet. A comparison of MPLS-based Metro Ethernet against a pure Ethernet MAN: • Scalability: In a properly designed Ethernet VLAN network, each switched path can have 4094 single tag VLANs.

Some aggregation and core switches can classify traffic by two VLANs using VLAN stacking, so with such aggregation devices properly placed in the center of a network, end segments and rings of single tag devices can receive only the traffic that they need. When using MPLS, Ethernet VLANs have local meaning only (like Frame Relay PVC). Same scalability considerations apply to the MAC addresses where in a pure Layer 2 Ethernet MAN all MAC addresses are being shared across the network, although this issue can be managed by smart network design and choosing switches with MAC tables sufficient for the size of network segments. • Resiliency: pure Ethernet network resiliency relies on a, or (30 to sub 50 ms convergence depending on network design) while MPLS-based MANs use mechanisms such as MPLS Fast Reroute to achieve SDH-like (50 ms) convergence times. Metro Ethernet can also use or where appropriate to add link redundancy and recovery in distribution networks.