Carrier-class Ethernet switches, 12/04/00

Carrier-class Ethernet switches

The Edge, 12/04/00

Riverstone hits ALL the hot buttons and is a good example of what a carrier-class switch should be. Riverstone's family of RS 8000, 8600 and 32000 switch routers are architecturally the same, and use the same operating software and I/O modules. These switches are deployed in service provider networks and metropolitan-area networks.

The RS 32000 switch/router is Riverstone's carrier-class switch, which addresses all carrier-class switch requirements.

Its large switch capacity of 128G bit/sec and high performance of 90 million packet/sec make it suitable for high-volume MAN traffic. Bandwidth control and provisioning within the RS family of switch routers can be conducted on bit-level increments from 1K bit/sec to 1G bit/sec.

Factoid

The 10G bit/sec Ethernet standard will be a major step up for Gigabit Ethernet switches used in MANs and service provider networks because it not only will provide the necessary bandwidth for backbones, but it also will enable seamless connections to OC-192 SONET links. The 802.3ae task force is developing a standard that will provide a fit between 10G bit/sec Ethernet and the OC-192 payload rate of 9.58464G bit/sec. This will let Ethernet be used as an end-to-end transport protocol.

This enables service providers to slice bandwidth into subscriber-specified increments and then dynamically allocate bandwidth on customer request. This lets service providers service multitenant buildings and campus environments, where multiple subscribers each want a segment of the overall bandwidth provided to a building.

Riverstone's hardware-based accounting characterizes each subscriber's traffic pattern, enabling service providers to track subscriber utilization and predict increasing bandwidth requirements.

Service providers must be able to accommodate a mixture of existing and emerging media, including

legacy copper and fiber. Although fiber to the curb is rapidly growing, it still accounts for only 10% of all building access. The remaining 90% is through copper cable via T-1, T-3 and DS-3 circuits running frame relay, PPP or ATM.

Riverstone's RS family of switches provides connectivity through a range of interfaces for deployment of services across virtually any infrastructure. Therefore, RS family interfaces include frame relay, T-1/E-1, DS-3/channelized T-3, ATM OC-12 and Packet over SONET (PoS), which supports OC-12 through OC-48. Riverstone's PoS support provides connectivity to SONET core networks.

Telseon, one of the new breed of MANs, uses Riverstone's RS switch routers in its network. Real-time bandwidth provisioning enables Telseon to respond to changing subscriber requirements. The company also provides its subscribers with a Web-based tool with which they can self-provision additional bandwidth. This capability is useful for temporary events Ñ for example, an hour-long videocast to all employees worldwide.

2. Foundry

Foundry's carrier-class entry is the BigIron 15000, a switch/ router with a whopping switch capacity of 480G bit/sec and performance of 178 million packet/sec. Foundry targets this switch to MANs and service provider networks for deployment in network backbones. Foundry provides an Ethernet offering for MANs that it calls Global Ethernet. Its BigIron switch provides short-, medium- and long-haul Gigabit Ethernet interfaces for connections to a MAN. Long-haul optics supports gigabit connections up to 150 kilometers, which means the switch can service corporate customers up to about 90 miles from the MAN.

On the core network side, Foundry provides connections to SONET core networks because SONET is the ubiquitous transport technology and is widely deployed. The BigIron switch provides PoS interfaces for OC-3, OC-12, OC-48 and, in the future, OC-192. Foundry does not support application flexible WAN interfaces such as frame relay, T-1/E-1 or DS-3. Instead, Foundry supports highly scalable Layer 2 virtual LANs for MAN subscribers, which it calls VLAN Super Aggregation because it scales up to 16 million VLANs. Each VLAN can then be used as VPN by a MAN subscriber. Foundry's Global Ethernet offering addresses multitenant building and campus network connectivity.

3. Extreme

Extreme has deployed its Black Diamond and Alpine series switch routers in several MANs and service provider networks. Extreme uses its WDM module to provide an optical backbone to connect its switches in the network, rather than connect its switches to a SONET core network. Its WDM module supports distances of up to 35 kilometers (22 miles) between switch locations. Extreme's Black Diamond 6816 is a carrier-class switch with a substantial switch capacity of 256G bit/sec and a performance of 192 million packet/sec. The Black Diamond 6808 provides half the switch capacity of the 6816 and half its performance.

Extreme's Alpine 3800 series switch routers also come in two sizes that provide either half or a quarter of the switching capacity and performance of the Black Diamond 6808. These incremental switch capacities enable Extreme to match switch capacity with bandwidth requirements within a network. Alpine 3800 switches can slice bandwidth to provision subscriber service in 500K bit/sec increments. The switches can be used to provision service in either the network core, the point of presence (POP) or the customer premises, such as in a multitenant building. Extreme also deploys its small Summit I series switches in POPs located on a customer premises as an aggregation switch. These switches also slice bandwidth for service provisioning.

Extreme's switches do not support WAN interfaces. They provide Ethernet interfaces only. Extreme interconnects the switches within a network using its wave division multiplexing (WDM) module. Extreme's strategy is to replace the SONET ring with a data-optimized optical ring via its WDM module as an Ethernet service provisioning platform.

Extreme supports voice over the network using a proprietary technique it calls IP Time Division Multiplexing, which adds circuit emulation to Layer 3 IP. This enables fixed, guaranteed latency circuits to be established for voice and video traffic over the network using fixed 64-byte packets and tagging techniques to identify voice traffic. Extreme also uses hardware-based billing techniques to meter traffic and utilization.