Jun Nojima, marketing director of NTT Corp’s domestic long-distance and international arm, said the Global Super Link, GSL, is a Layer-2 Ethernet service delivered over an MPLS core, itself running on the IP backbone NTTCom first acquired in 2000 when it bought ISP and hosting provider Verio Inc for $5.5bn. Since then it has added more transoceanic fiber capacity.
Nojima said the target market for GSL is twofold: Japanese companies going out into the international market and US, and European companies going into Asia. You won’t find us bidding from intra-regional business in the EU, because that’s not where out sweet spot it, he said, but you will see us where a global network with extensive Asian presence is required. An example of this is NTTCom customer Renault Nissan Information Systems, where the French vehicle manufacturer has merged operations with a Japanese counterpart and now needs a lot of bandwidth in and around Asia.
Mahoko Tamura, product manager in NTTCom’s Global Business Division, said GSL supports the three network topologies defined for Carrier Ethernet services by the Metro Ethernet Forum. These are: point-to-point (what the MEF calls Ethernet Private Line, or EPL); point-to-multipoint (Ethernet Virtual Private Line, or EVPL); and multipoint-to-multipoint (any-to-any, Ethernet LAN, or E-LAN). Customers take an Ethernet tail into one of NTTCom’s GSL nodes, from where its traffic is passed on to the MPLS core and out the other end via another node. The carrier puts customers’ traffic on to individual VLANs to traverse its network core. Since we support VLAN tagging, the customers can also use their own VLANs, she said.
Other than in Japan where NTT is the former monopoly operator and has its own nationwide Ethernet network, tails will be leased from third parties, which initially means other incumbents. Nojima said the acquisition of Verio helped quite a lot because it had Tier-1 carrier status, which is a significant advantage in negotiations with other big operators. However, to exploit the potential for further arbitrage, more suppliers will be added. We’re starting out with the incumbents to provide tails, but the plan is to have a couple of carriers per country, he said.
Pricing is an area the Japanese carrier believes it can differentiate its services. It will offer both flat-rate charging that starts with 10Mbps and grows in 10Mb-increments through to and including 100Mbps, or a charge that varies with usage, delivered over a 100Mbps pipe. We haven’t seen the competition offering this kind of flexible charging for international corporate usage, even though it’s quite popular for internet services, said Tamura.
GSL was first launched for the US market in July 2005, and the paucity of Ethernet carriers there led NTTCom to offer the service with legacy first miles such as DS3 and STM1, with the traffic going into an intelligent Ethernet converter box at the node for transmission across the MPLS core. That need has not arisen in Europe, said Tamura, because there are a variety of Ethernet services available.
For this reason, the service has now been rolled out to the UK, France, Germany, and the Netherlands, as well as the first Asian node outside Japan, in Hong Kong. GSL is the Ethernet complement to the IP VPN services NTTCom has been offering internationally since the beginning of 2001, said Nojima. The difference is that these services are delivered over an MPLS infrastructure on leased lines, rather than the IP backbone.
Beyond those geographies, Tamura predicted the focus will be on Asia, since the ability to offer more WAN services in growth markets like China and India is another way the carrier seeks differentiation in the eyes of its Fortune Global 1000 target market from the likes of BTGS, Equant (now Orange Business Services), AT&T, and Verizon.
BTGS recently tightened its relationship with NTT’s largest domestic rival in wireline, KDDI Corp, which went from being a BT Infonet reseller to setting up a joint venture with BT to offer managed international voice and data services to the Japanese carrier’s corporate customers. They too cite an automaker, Toyota, as an example of such business. KDDI struck a deal with the car company to connect all its European subsidiaries with IP VPNs on the Infonet network in 2004.
Q-in-Q is fine while the number of customers isn’t too large. It supports up to 4,096 VLANs on a network. However, Carrier Ethernet services will need to support millions of customers, and NTTCom is already looking at what technologies it might deploy down the road, with a decision likely in the next year.
One option for greater scalability would be Virtual Private LAN Services, or VPLS, which is really Ethernet with an MPLS control plane, which has potential downsides such as questionable performance on the operations, administration, and management front, as well as the relative complexity and cost of the network. Tamura said this could be mitigated, at least from the customer’s perspective, by running the VPLS service only to the GSL node, then just go native Ethernet to the customer premises.
Another alternative would be a pure Ethernet service with MAC-in-MAC technology, as specified in the putative 802.1ah standard from the IEEE. This is the equivalent of Q-in-Q but with the ability to stack entire packets from the MAC address on, which makes it possible to support over 16 million VLANs, which solves the scalability problem. With full encapsulation, carriers can guarantee the complete isolation of individual circuits. Another term being used in the service provider space for this technology is Provider Backbone Bridging, or PBB.
NTTCom has already been offering a form of MAC-in-MAC technology, or what it calls Ethernet over Ethernet, since November 2001 in the Japanese market, where it was provided by a local equipment vendor. Mototsugu Kani, assistant manager of NTTCom’s Global Business Division, said it could roll that service out internationally, but it is a non-standard implementation, not least because it pre-dates the IEEE’s work on 802.1ah. But with the standard now close to completion, he said, we have another alternative to consider: PBB, provided by a different vendor.
