Since the 1980s, Ethernet has been the network protocol of choice for local area networks (LANs). For wide area
networks (WANs) the choices have been many, including frame relay, asynchronous transfer mode (ATM) and multiprotocol label switching (MPLS). With Ethernet advantages like efficiency and low cost, it's no surprise that WAN carriers and users have embraced Ethernet as an offering. WAN speeds using Ethernet are currently into the multiple gigabits per second range and increasing. But if your organization has traditionally used non-Ethernet WAN services, how do you decide if a migration to Ethernet makes sense? We'll examine some of the advantages and disadvantages of Ethernet on WANs in this article.
The evolution of Ethernet and WAN connectivity
While MPLS and other established WAN protocols are alive and well, Ethernet penetration of the WAN market has been significant in recent years. Even with dramatically cheaper prices for T-1 channels (i.e., $150 to $400 per month), the costs for Ethernet WAN service are very favorable (as little as $5 per megabyte, compared to T-1 at $200 to $300 per megabyte), and the rapid acceptance of 10 Gigabit Ethernet (10 GbE) service is a testament to Ethernet's acceptance by the WAN and metropolitan area network (MAN) communities. In reality, it's likely Ethernet and MPLS will coexist and become increasingly difficult to decide between.
Ethernet versus MPLS versus others
Virtual private networks (VPNs) and their routing protocols can be managed two ways: by you or your carrier. In either case, the protocol of choice has been MPLS, as it can be used either at Layer 2 (where you control the routing) or Layer 3 (where carriers control the routing). By contrast, Ethernet is a Layer 2 protocol that gives users (and carriers if they are providing the service) routing control. Current WAN protocols are not expected to disappear in the near term, and will be competing with Gigabit Ethernet. For more on MPLS vs. Ethernet, please refer to this article: The pros and cons of MPLS vs. Ethernet.
Assuming high-speed Ethernet -- like Gigabit Ethernet, 10 GbE and 100 GbE -- will be the principal Ethernet WAN protocols, its advantages are many. For example, if your organization has several buildings or sites connected in a campus or metropolitan area, 10 GbE can be a cost-effective way to link these sites. This is because 10 GbE is a full-duplex protocol and is fully compatible with any Ethernet-based network. The 10 GbE standard, which also supports single-mode and multi-mode fiber systems, is expected to be compatible with twisted-pair copper, and can connect to synchronous optical network (SONET) and synchronous digital hierarchy (SDH) wide area networks. An all-Ethernet infrastructure greatly simplifies the entire network management process, because every device uses essentially the same protocol to communicate. By contrast, situations where multiple protocols coexist in the WAN mean that network management and diagnostic systems must be compatible with all protocols in use for network administrators to analyze network performance. The ultimate Ethernet advantage is high-speed, low-latency end-to-end communications.
Advantages of Ethernet speed
With development of the 40 and 100 Gigabit Ethernet protocol (IEEE 802.3ba), speeds well beyond the current 10 GbE protocol are available. The technology adheres to the principal Ethernet protocols and interfaces, while significantly boosting speeds and reducing network latency in the process. Manufacturers of 40 GbE and 100 GbE systems include Alcatel-Lucent, Brocade Communications Systems, Cisco Systems, Huawei Technologies Co. and Juniper Networks.
For most users, the 10 GbE standard will probably be entirely sufficient for most WAN and MAN applications, but very large users with heavy bandwidth and low latency requirements should find the 40 or 100 GbE standard worth considering.
Decision criteria for Ethernet on WANs
When examining other Ethernet advantages and disadvantages for WAN connectivity, consider the following:
- Analyze Ethernet costs, performance, latency, reliability, technical support and security. You have three ways to accomplish this:
- analyze your network performance data and compare it with your test of Ethernet performance data;
- research vendor and carrier experience with Ethernet; or
- retain an experienced network consultancy to provide an analysis.
- Determine your medium- and longer-term demands for bandwidth, throughput and latency, and analyze them against your current WAN infrastructure. Will the current WAN be sufficient? How easy/difficult/costly will it be to boost WAN performance?
- How important is it to have an all-Ethernet infrastructure from cost/benefit and performance perspectives versus your current mixed-protocol environment?
- How important is it for your WAN to link to other organizations, like subsidiaries or supply chain members, and will a difference in network protocols affect your organization's business operations?
→ For more information, use these WAN Ethernet deployment tips.