Today’s global enterprise and service provider networks require diverse networking solutions to meet both economic and evolving connectivity needs. The demand for high-density, cost-effective solutions increases as corporate intranets expand to include more regional offices and increased numbers of remote and mobile users.

The Cisco 8-Port Channelized SPA T1/E1 Version 2 (Figure 1) provides one of the greatest densities currently available in the industry at 8 ports per SPA and up to 32 ports per SIP. The cost per T1 or E1 port is less than that of a standard serial port with external channel service unit (CSU) or data service unit (DSU), which makes the Cisco 8-Port Channelized T1/E1 SPA Version 2 cost-effective for all WAN connectivity.

This SPA is designed to provide a full 8-port channelized solution for Cisco 6500 Series, 7600 Series, ASR1000 Series, ASR9000 Series and 12000 Series Routers. The interfaces can be channelized, fractional, or unframed (E1) with up to 256 independent High-Level Data Link Control (HDLC) channels definable for T1 and E1 applications. With these capabilities, the Cisco 8-Port Channelized SPA T1/E1 Version 2 eliminates the need for separate interface types for separate connection requirements.

Multilink Point-to-Point Protocol (MLPPP) is supported in hardware to allow link aggregation greater than T1 capacity. Up to eight individual T1s can be combined within a multilink bundle that appears to be a single IP link. As a result, service providers can provision greater-than-T1 bandwidth incrementally, without migrating the circuit and customer premises equipment (CPE) infrastructure to T3 facilities.

The Cisco 8-Port Channelized T1/E1 SPA Version 2 is hot-swappable and supports service-transparent online insertion and removal (OIR), allowing removal of the adapter without affecting the interface processor and other SPAs.

Applications
The Cisco 8-Port Channelized T1/E1 SPA Version 2 is ideal for service providers and large enterprises that want to cost-effectively deploy high-density terminations for multiple remote sites (Figure 2). The SPA helps enable applications that need to terminate remote and branch-office locations on a single router in a corporate enterprise network. For service provider applications where only DSU functions are required (for example, at sites colocated with a carrier), the Cisco 8-Port Channelized T1/E1 SPA Version 2 provides high port density at a reduced cost per port. For E1 applications, the channelized E1/G.703 interface allows direct connectivity to 120-ohm G.703 lines.

The Cisco 8-Port Channelized T1/E1 SPA Version 2 offers many advantages, including:
- Eight software-configurable T1 or E1 ports
- Support for channelized and fractional T1 and E1, as well as clear channel E1
- 256 independent HDLC channels
- Integrated CSUs and DSUs
- Support for all major encapsulations, including MLPPP and multilink Frame Relay (MLFR)
- Support for link fragmentation and interleaving (LFI) over Frame Relay and MLPPP