HP StorageWorks 6000 HP StorageWorks VLS and D2D Solutions Guide (AG306-96028, - Page 94

This is a flexible bandwidth solution with speeds between 64 Kbps and 1 Gbps. The router is provided by BT and is designed primarily for internet access. The connection is typically to a BT point of presence POP and optional features such as failover and load balancing are available. The connection to the BT POP would be copper wire for the lower speeds (SDSL type connection) (64 Kbps, 2 Mbps) and optical fibre at the higher speeds. A VPN would need to be set up to connect to another sites subnet. This would be necessary for a D2D replication connection. Contention may be an issue with this type of service. • BT Etherflow This service is a high-performance WAN services delivered as an ethernet connection but with the end user retaining end to end control over the IP architecture and the ability to support non-IP applications such as AppleTalk, IPX, DECNet and SNA. Speeds are available between 1 Mbps and 1 Gbps. Building blocks are available to create VPNs and separate traffic classes. (Traffic could be separated for different groups within a company or for IP telephony.) This service is optical fibre based. This service could be used for D2D replication but would typically provide other services on site already (connections to servers located at a central site). This technology also runs on BT 21st century Network-MPLS. • BT IP Clear This service provides network integration using the Telcos MPLS infrastructure and is suitable for the larger corporate network. It provides a full range of access and is delivered to user locations by leased line from 128 Kbps up to 1 Gbps through optical fibre. All routing and VPNs are handled by the MPLS core and typically a user would be provided with an edge router. Voice circuits (IP telephony) can be fully integrated into this service. • BT Ethernet extension services This service provides high speed dedicated links using permanent optical fibre connections. LAN speed from 10 Mbps to 1 Gbps is supported. Alternative protocols can be used such as ATM and fibre channel. Using this service the LAN could span several sites with no VPNs. There is a distance limit of 25 km between sites (can be expensive). Table 12 Sample British Telcom Services and Speeds Service Available speeds Suitable for D2D low bandwidth replication BTnet Premium BT Etherflow BT IP Clear BT Ethernet Extension 64 kbps to 1 Gbps 1 Mbps to 1 Gbps 128 Kbps to 1 Gbps 10 Mbps to 1 Gbps Yes (2 Mbps upwards) need VPN and fixed IP. Contention? Yes-2 Mbps upwards Yes-2 Mbps upwards Yes but limited distance and likely to be expensive When to use BT Etherflow and when to use BT IP Clear? • BT Etherflow is the right choice for users who want an Ethernet (Layer 2) hand-off and seek to retain end to end ownership of their IP Architecture. It best suits users with a small numbers of high bandwidth sites. • IP Clear is the right choice for users who want an IP (Layer 3) hand off and wish to share their IP architecture with BT. It offers any to any connectivity and is best suited to users with a large number of low bandwidth sites. 94 D2D Systems