The extensible Cisco ® I-Flex design combines shared port adapters (SPAs) and SPA interface processors (SIPs), enabling service prioritization for data, voice, and video services. Enterprise and service provider customers can take advantage of improved slot economics resulting from modular port adapters that are interchangeable across Cisco routing platforms. The I-Flex design maximizes connectivity options and offers superior service intelligence through programmable interface processors that deliver line-rate performance.

I-Flex enhances speed-to-service revenue and provides a rich set of quality-of-service (QoS) features for premium service delivery while effectively reducing the overall cost of ownership. This data sheet contains the specifications for the Cisco 1-Port and 3-Port OC-3c/STM-1c ATM, and Cisco 1-Port OC-12c/STM-4c ATM Shared Port Adapters (refer to Figure 1).

This data sheet details the features of the new modular ATM SPAs for Cisco XR 12000 Series Routers, the Cisco CRS-1 Carrier Routing System and the Cisco ASR 1000 Series. The Cisco ATM SPAs, in conjunction with other SPAs implementing various types of network technologies, allow the user to flexibly build cost-effective routing solutions focusing on point-of-presence (POP) edge, customer premises equipment (CPE), and enterprise applications.

Designed for all telcos and Internet service providers (ISPs), the Cisco ATM SPAs support a variety of port choices and granularity, including OC-3c/STM-1c and OC-12c/STM-4c interfaces for worldwide use. These modules are designed to support the convergence of data, voice, and video services, allowing customers to migrate existing voice and video traffic onto a corporate data network for substantial cost savings.

The Cisco ATM SPAs include a comprehensive ATM feature set including per-virtual-circuit and per-virtual-path traffic shaping, ATM service classes including constant bit rate (CBR), variable bit rate non-real time (VBR-nrt), variable bit rate real time (VBR-rt), unspecified bit rate (UBR), Multiprotocol Label Switching (MPLS), QoS, a high-performance segmentation-and-reassembly (SAR) architecture, and support for a large number of ATM virtual connections. All these features are based on industry specifications and standards. In conjunction with the SIPs, the Cisco ATM SPAs continue to deliver new features made possible by industry-leading Cisco IOS ® Software protocols, services, and an ATM-rich feature set.

The Cisco ATM SPAs address the growing demand for improved ATM QoS features, which are combined with the advanced Layer 3 class-of-service (CoS) capabilities provided by various Cisco routers. Robust QoS mechanisms help prioritize traffic from traditional and high-speed LANs over an ATM network. Network managers can now cost-effectively terminate high-speed ATM, enabling rich QoS features for aggregation or campus applications.

The Cisco ATM SPAs can be inserted in the Cisco SIPs that support various edge services such as:

- IPv4, IPv6, and MPLS hardware-assisted forwarding
- Enhanced security features such as extended access control lists (ACLs), Unicast Return Path Forwarding (URPF), Internet Control Message Protocol (ICMP) rate limiting, and others
- Extensive QoS implementation based on either "classical" QoS (three type-of-service [ToS] bits), Differentiated Services (DiffServ [six DiffServe code point (DSCP) bits]), or MPLS (3 bits EXP)
- Enhanced NetFlow, statistics, and billing data to allow service providers to generate different billing profiles for their customers
- MPLS-VPN support that allows for Layer 3 VPN deployments and various related applications
- Any Transport over MPLS (AtoM) or pseudowire edge-to-edge emulation 3 (PWE3) support for transport solutions

The Cisco ATM SPAs use replaceable Small Form-Factor Pluggable (SFP) optical modules that allow customers the flexibility to use different optical interfaces on the same SPA. The Cisco ATM SPAs are hot-swappable and support service-transparent online insertion and removal (OIR), allowing removal of the SPA without impacting the interface processor and other SPAs.