Ethernet Technology Encyclopedia (II)

Whether from the demand side or from the supply side, the overall network is moving towards broadband, which gives Ethernet a good space for development. From a technical point of view, over the past 20 years, Ethernet bandwidth from 10 trillion, hundred trillion, gigabit, has been developed to 2002 million trillion, or even 40,000 trillion, 100,000 trillion are already in the research and discussion stage, which makes Ethernet technology has a good scalability; from the application side, Ethernet is not only limited to the application of LAN, Not only limited to the application of the metropolitan Area Network, Gigabit Ethernet further extends Ethernet to the wide area network, which makes the concept of "global Ethernet" that we have pushed in the past become more practical and feasible. It would be more feasible to cooperate with the new broadband access technology that the IEEE EFM Working group established at the end of 2000 (Ethernet in the Mile), or the current popular Ethernet community access and building access, to provide End-to-end Ethernet solutions. Thus, more than IP unified the upper network, Ethernet also unifies the lower network, through the IP, through the Ethernet, the entire Network end-to-end form from the access network, the metropolitan area network to the WAN between seamless connection, from the network investment cost, the logic management, the compatibility, as well as the End-to-end service quality (QoS), Ethernet has a considerable competitive advantage. (Computer science)

End-to-end Ethernet Solution with Ethernet as the access technology, not only low-cost, and bandwidth than the current cable modem, ADSL, ISDN, modem access are high, so not only as a general user Internet connection, or multimedia on demand or broadcast use, It can be used as enterprise user to realize VPN virtual private network interconnection; All branches of large enterprises can realize intranet VPN interconnection through End-to-end Ethernet, enterprise and its partners can realize enterprise external VPN interconnection through End-to-end Ethernet.

Finding a low-cost, high-bandwidth, secure VPN interconnect solution for users or carriers is a key issue, and the answer lies in the simplest 802.1p/802.1q VLAN standard, where we can use a two-tier VLAN technology to provide VPN services, But there are a few issues that need to be addressed.

Bandwidth management for end users

Different users have different bandwidth requirements, or based on the user pay principle, different cost levels of users can enjoy different bandwidth, so access devices must support the bandwidth throttling function.

Quality of Service (QoS) mechanism

Different business needs different quality of service assurance, or different levels of users have different service levels, whether through the two layer of 802.1p or three layer of IP TOS technology to achieve, network devices must be able to classify, mark, even measure or reshape, in order to implement the QoS mechanism.

The expansion of the VLAN

The number of VLANs based on the 802.1p/802.1q VLAN is only 4,096 VLANs, which may be sufficient for enterprise networking, but for operators to provide VLAN based VPN services, 4,096 VPNs cannot meet the needs of a growing number of customers, Therefore, the number of VLANs must be extended considerably.

The current Super VLAN technology adds a set of VLAN tags to the original grouping (only one VLAN tag), allowing the number of VLANs to be extended to 4096x4096, which is equivalent to slicing the End-to-end VLAN into the backbone VLAN and the Edge VLAN. The backbone VLAN is similar to the VPI in ATM, and the Edge VLAN is similar to the VCI in ATM.

VLAN Security and user isolation

With a two-tier VLAN as a VPN use, cross-VLAN interconnection has been basically blocked, thus providing basic security features, operators can even use more tools such as ACLs, MAC address filtering, etc. to enhance security performance. If it is necessary to isolate different users under the same VLAN, private VLANs are also one of the ways to do this.

Convergence, expansion and diversion of Spanning Tree Protocol (STP)

Using End-to-end Ethernet VLAN technology to provide a two-tier VPN service will form a large two-tier network, for STP, whether it is the convergence time of redundant links, the expansion of network topology or blocking link (block) bandwidth utilization will cause great impact. Therefore, it is necessary to introduce techniques such as fast spanning tree (RSTP), super Spanning tree (Hyper STP), VLAN group spanning tree (RVGST) to enhance the extensibility of Spanning Tree Protocol (STP) in large scale networks.

Non-spanning Tree protocol technology

In larger networks, it is also possible to consider the use of loop topologies such as RPR (resilient Packet ring), MRP (Metro ring Protocol), or VSRP (Virtual Switch redundant PROTOCOL) star topology technology to replace the spanning tree protocol, so that the fiber resources to achieve more savings, the convergence of the network to a second-level level.

Ethernet Traversing SDH Backbone network

When End-to-end Ethernet traverses the backbone, not all backbone networks are supported by a metropolitan area network of hundred gigabit/Gigabit Ethernet. More often, Ethernet must traverse the SDH backbone to reach the other side of the Ethernet network, so providing Ethernet VLAN functionality across SDH is a necessary function.

After years of development, Ethernet technology has basically solved the above several main problems, due to the high popularity of Ethernet and the continuous evolution of VLAN technology, in the End-to-end Ethernet network to adopt two-tier VLAN technology to achieve the VPN business is not only simple, low-cost, high bandwidth, and very high compatibility, for individual users or operators, VPN interconnect value-added services are a highly feasible solution for End-to-end Ethernet, and customers do not have to wait for MPLS VPN. (The writer is foundry technology manager in Asia Pacific).