Cisco 2600, 3600 and 3700 Series Multiport T1/E1 ATM Network Modules with InverAllow service provider and enterprise customers to cost-effectively increase bandwidth, extending multiservice capabilities to remote branch-office locations using ATM.se Multi

Cisco 2600, 3600 and 3700 Series Multiport T1/E1 ATM Network Modules with Inverse Multiplexing over ATMAllow service provider and enterprise customers to cost-effectively increase bandwidth, extending multiservice capabilities to remote branch-office locations using ATM.

Introduction

Four multiport T1/E1 ATM network modules with Inverse Multiplexing over ATM (IMA) are available for the Cisco 2600, 3600, and 3700 series multiservice access platforms. Available in both four- and eight-port versions, these new multiport ATM modules allow service provider and enterprise customers to cost-effectively increase bandwidth, extending multiservice capabilities to remote-branch-office locations through ATM.

These multiport T1/E1 ATM network modules with IMA add to the broad Cisco portfolio of customer premises equipment (CPE), ATM edge, and central-office products, that allow branch offices to take advantage of the higher bandwidth and multiservice capabilities available from ATM services. These new ATM modules complement the existing OC-3 and 25-Mbps family of ATM network modules available for the Cisco 2600, 3600 and 3700 series that now offer ATM bandwidth from 1.544-Mbps to 155-Mbps.

The high cost and limited availability of long-distance broadband ATM services have prevented many organizations from taking advantage of ATM's high quality-of-service (QoS) features. In recent years the ATM Forum has defined lower-speed T1/E1 ATM services, but this was an incomplete solution because a single T1/E1 often does not provide sufficient bandwidth to support the additional requirements of multiservice applications. For this reason, many organizations find themselves caught between the bandwidth limitations of narrowband T1/E1 lines and the much higher costs of moving to broadband links.

In response to this the ATM Forum, with Cisco as an active member, defined a standard for IMA. Using the Cisco 2600 and 3600 series multiservice platforms to provide IMA access provides an affordable LAN-to-WAN solution for branch office, campus and ATM Edge applications. Multiport T1/E1 IMA modules enable service providers to deliver critical integrated ATM services combining data, voice and video with ATM's guaranteed QoS features. With multiport IMA deployed as CPE edge, network service providers can deliver unmatched flexibility in the types of services they can offer to their customers.

IMA is an ATM Forum specification that provides a cost-effective and scalable alternative to T3/E3 services by allowing carriers to leverage widely available T1 services over ATM and interoperate with other vendors' standards-based equipment. Multiport T1/E1 IMA can provide organizations with highly desired fractional T3 bandwidth connectivity, which is critical in situations where DS3 or OC-3 fiber connections are either cost-prohibitive, or unavailable between a provider's central office and the customer's premises.

Multiport T1/E1 IMA network modules functionality allows access to ATM WAN uplinks with bandwidth requirements between DS1 and DS3 rates. Each T1 link provides 1.544 Mbps and each E1 link provides 2.048 Mbps connectivity. With IMA's aggregation of multiple T1/E1s, network managers have the ability to increase bandwidth inexpensively to allow wide-area network (WAN) uplinks at speeds ranging from 1.544-Mbps to 16-Mbps full-duplex on a single card.

All four multiport ATM network modules support the ATM Forum Adaptation Layer 5 (AAL5) with ATM QoS categories Unspecified Bit Rate (UBR), Variable Bit Rate (VBR-rt and VBR-nrt), and Available Bit Rate (ABR). VoIP and H.323 video over ATM can be supported using VBR-rt class of service (CoS) parameters with the currently available analog voice/fax network modules with voice interface cards (VICs), or the new T1 digital packet voice trunk network modules with multiflex trunk cards.

The multiport T1/E1 IMA modules' support for VoIP and H.323 video applications provides low latency, jitter-free voice support to enhance throughput, and high-quality, end-to-end voice and video performance. When combined with high-density packet telephony solutions already available on the Cisco 2600 and 3600 series, the multiport ATM network modules provide a seamless end-to-end multiservice solution, interoperable with other ATM Forum IMA version 1.0 products available from Cisco.

Multiport T1/E1 ATM Network Modules: New Features at a Glance

Supported on all Cisco 2600 and 3600 series multiservice platforms

Supports four or eight T1/E1 ATM ports

Support for ATM Forum IMA Version 1.0

Up to 16-Mbps full-duplex bandwidth with an 8-port E1 IMA network module

Supports UBR, VBR-rt, VBR-nrt, and ABR ATM CoS

Maximum of four active IMA groups on both four- and eight-port versions

Integrated CSU/DSU on T1 versions

Integrated DSU for E1 versions

ATM Forum User Network Interface (UNI) 3.0, UNI 3.1, and UNI 4.0 signaling

ATM Adaptation Layer 5 (AAL5)

Permanent Virtual Circuits (PVCs) and Switched Virtual Circuits (SVCs)

Request For Comments (RFC) 1483 support for multiple encapsulations over ATM

RFC 1577 support for Routing over ATM

Maximum of 256 Virtual Circuits (VCs) per interface with up to 1024 simultaneous reassemblies per card

Maximum differential delay tolerance of up to 200-ms

F4 and F5 Operation, Administration, and Maintenance (OAM) cell support

Cyclic Redundancy Check(CRC)32 error checking of AAL5 and CRC10 checking of operations and management (OAM) cells

Internet Engineering Task Force (IETF) Point-to-Point Protocol (PPP) over ATM

Multiprotocol over ATM (MPOA) client and server

LAN emulation (LANE) 2.0 client only

Tag Switching (packet interfaces only)

Interim Local Management Interface (ILMI)

Next Hop Resolution Protocol (NHRP)

ATM bandwidth (resource) manager

IMA Benefits

The multiport T1/E1 ATM offers the following benefits:

Inexpensive ATM access

A migration path to higher bandwidth without the need to change transport facilities

ATM Forum Version 1.0 standards compliant (AF-PHY-0086.000) for multivendor interoperability

Integrated CSU/DSU on T1 versions and integrated DSU on E1 versions

The addition and deletion of links without service disruption

Support for link failures and automatic link recovery without loss of data

Greater internetworking design flexibility and scalability for LAN-to-WAN connectivity

Efficient prioritization of mission-critical data provided by ATM's QoS features

Simplifies network management

Eliminates third-party inverse multiplexing devices.

Cisco NM-4T1-IMA