CISCO AS5350XM UNIVERSAL GATEWAY
The Cisco® AS5350XM Universal Gateway is a one-rack-unit (1RU) gateway that offers best-of-breed voice, fax, and remote-access services and supports 2-, 4-, or 8-port T1/7-port E1 configurations. It doubles the performance of the Cisco AS5350 and delivers significant memory enhancements to offer high performance and high reliability in a compact, modular design. The Cisco AS5350XM Universal Gateway supports existing Cisco AS5350 trunk termination and universal port feature cards in a more powerful chassis to help ensure continuing network investment protection. This cost-effective platform is ideally suited for service provider and enterprise environments that require innovative voice, fax, and data services.

(Cisco AS5350XM Universal Gateway )

FLEXIBILITY TO DEPLOY NEW SERVICES
Demand for new services can be easily accommodated with the Cisco AS5350XM Universal Gateway (Figure 1), whether the initial business opportunity is voice services over broadband, wholesale voice transport, unified communications, call-center services, IP-enabled interactive voice response (IVR), hosted IP telephony, prepaid calling card, Common Channel Signaling System 7 (SS7/C7) interconnect, high-volume Internet access, regional or branch-office connectivity, corporate VPNs, or wholesale dial. The flexibility to use the Cisco AS5350XM in multiple service environments provides unprecedented capital investment protection. It helps ensure that the network can promptly adapt to changes in the business environment and meet the demands of the marketplace for new services.

CISCO AS5350XM UNIVERSAL GATEWAY HELPS ENABLE NEW CISCO SERVICES
The Cisco AS5350XM Universal Gateway supports a wide range of IP-based, value-added voice, fax, and data services. It helps service providers with existing data networks quickly and easily add voice services to their portfolios, and carriers that offer voice services over existing TDM networks can expand their coverage more cost-effectively. The Cisco AS5350XM provides the perfect solution for telephony application service providers (ASPs) that want to deploy PC-to-phone, voice portals, voice-enabled Web commerce, and content delivery services.

The rich set of Cisco IOS® Software features available in the Cisco AS5350XM Universal Gateway helps Internet service providers (ISPs) and enterprise network managers meet traditional dial-in access needs, including Internetwork Packet Exchange (IPX) and AppleTalk, while supporting the migration to new universal port services.

Cisco Systems® customers worldwide have proven that Cisco AS5000 universal gateways provide the flexibility, scale, reliability, and suite of services required to meet market demands. By providing the industry's broadest family of voice gateway and access server products with universal port digital signal processors (DSPs), Cisco makes it easy for customers to select the right starting point for a phased rollout based on revenue generation, without compromising future capabilities. Complemented by the industry's highest-rated service and support, Cisco also can provide assistance with startup, maintenance, and marketing tasks, as well as advanced and custom solutions.

YOUR COMPLETE POINT-OF-PRESENCE SOLUTION
The Cisco AS5350XM Universal Gateway eliminates the need for switches and routers to create a point-of-presence (POP) or "POP-in-a-box" solution. The gateway has three primary universal gateway configurations: two Channelized T1 (CT1)/Channelized E1 (CE1)s, four CT1/CE1s, and eight CT1/seven CE1s. It also includes integrated signaling-link-termination (SLT) functions for direct connection to an SS7/C7 signaling gateway.
The Cisco AS5350XM Universal Gateway comes with two 10/100/1000BASE-T autosensing Gigabit Ethernet ports, which are perfect for redundancy and firewall applications. Additionally, two high-speed serial ports are provided to support Frame Relay, Point-to-Point Protocol (PPP), and High-Level Data Link Control (HDLC) backhaul. All Ethernet interfaces support Hot Standby Router Protocol (HSRP), and all cards and the fan tray are hot-swappable for carrier-class resiliency. Availability is further enhanced with the optional AC or DC redundant power supplies. The Cisco AS5350XM is the only gateway in this form factor that offers voice, fax, and remote-access capabilities with these high-availability features.
The Cisco AS5350XM Universal Gateway also supports widely deployed routing protocols, including those generally found in high-end access servers and routers (for example, Border Gateway Protocol Version 4 [BGPv4], Open Shortest Path First [OSPF], Enhanced Interior Gateway Routing Protocol [EIGRP], and Intermediate System-to-Intermediate System [IS-IS]). This capability allows service providers and enterprises to deploy the Cisco AS5350XM Universal Gateway as a standalone universal gateway solution.

FEATURES AND SOLUTIONS
Packet Telephony
With more than 18 million voice gateway ports shipped, Cisco is a proven leader in product innovation for packet telephony services. Cisco AS5000 universal gateways are a primary component in many Cisco end-to-end voice solutions:

The framework for VoIP services on the Cisco AS5350XM Universal Gateway is based on open interfaces and industry standards, and it allows an ecosystem of partners to work together to develop innovative network services. Service providers are not locked into a single VoIP signaling technology when they choose the Cisco AS5350XM-Session Initiation Protocol (SIP), H.323, Media Gateway Control Protocol (MGCP), and Trunking Gateway Control Protocol (TGCP) support are all built in. This allows service providers to enable the call-control protocol that is the best fit for their network today, with the assurance that they can respond to evolving market requirements whenever necessary.

SIP
SIP is a peer-to-peer, multimedia signaling protocol that integrates with other Internet services, such as e-mail, voicemail, instant messaging, multiparty conferencing, and multimedia collaboration. When used with an IP infrastructure, SIP helps enable rich communications with numerous multivendor devices and media. SIP is the IETF standard for multimedia conferencing over IP. Defined originally in RFC 2543 and updated with RFC 3261, SIP is an ASCII-based, application-layer control protocol that can be used to establish, maintain, and terminate calls between two or more endpoints.

Cisco has been instrumental in defining SIP standards. The company has been at the forefront of SIP technology since the first SIP IETF RFC was published in 1999. As the IETF co-chair for multiple SIP working groups, Cisco actively contributes to SIP standards.

The SIP implementation on the Cisco AS5350XM Universal Gateway includes support for RFC3261 as well as critical features such as third-party call control and RFC 2833: RTP Payload for DTMF Digits, Telephony Tones, and Telephony Signals. The Cisco AS5350XM also supports many important SIP extensions, including RFC 3262: Standard for Reliability of Provisional Responses in SIP (PRACK), and RFC 3264: Standard for Offer/Answer Model with Session Description Protocol (SDP).

H.323
Leading the industry through the adoption of new standards-based H.323 technology, the Cisco AS5350XM Universal Gateway supports the scalability enhancements introduced in H.323v2 and H.323v4. For example:

H.323 operates in most VoIP backbone networks today, carrying billions of call minutes in many of the world's largest VoIP networks. H.323-based services continue to grow in service provider usage and profit.

Similarities Between SIP and H.323
Although SIP messages are not directly compatible with H.323, both protocols can coexist in the same packet telephony network because the Cisco AS5350XM Universal Gateway can process individual SIP and H.323 calls simultaneously. This allows service providers to integrate complementary H.323 and SIP services in the same network.

Both protocols are essential for solutions where an intelligent media gateway is used for public-switched-telephone-network (PSTN) termination.

MGCP
MGCP 1.0 is a protocol for centralized control of VoIP calls by external call-control elements known as media gateway controllers (MGCs) or call agents. MGCP is described in the informational RFC 3660: Basic Media Gateway Control Protocol (MGCP) Packages, published by the IETF.

Package Types
An MGCP call connection involves a series of events and signals-such as off-hook status, a ringing signal, or a signal to play an announcement-that are specific to the type of endpoint involved in the call. MGCP groups these events and signals into packages. A trunk package, for example, is a group of events and signals relevant to a trunking gateway; an announcement package is a group of events and signals relevant to an announcement server.

The Cisco AS5350XM Universal Gateway supports the following MGCP package types:

The Cisco AS5350XM Universal Gateway includes support for the MGCP NAS package. This allows the platform to operate simultaneously as a NAS and a voice gateway to deliver universal port services in an MGCP network. Standards-based T.38 Fax Relay and RFC 2833 DTMF Relay are available with MGCP.

Voice Quality
The extensive voice and fax capabilities of the Cisco AS5350XM Universal Gateway can help build a reliable, high-quality VoIP network. Voice-quality tests confirm that the Cisco AS5350XM delivers end-to-end voice-quality performance that meets the high standards established for toll-quality voice services in the PSTN. Comprehensive voice-quality testing is a critical component in the Cisco AS5350XM development process. Cisco conducts subjective voice-quality tests to determine mean opinion scores using a methodology derived from ITU-T Recommendations P.830 and P.831. Objective voice-quality tests are also conducted using the Perceptual Evaluation of Speech Quality (PESQ) algorithm (P.862), an enhanced perceptual measurement for voice quality in telecommunications specifically developed for end-to-end voice-quality testing under real network conditions.

The high-performance design of the Cisco AS5350XM Universal Gateway minimizes delay and packet loss during voice encoding and packetization processes. The Cisco AS5350XM introduces minimal delay because voice data is received from the PSTN and transmitted to the IP network. Cisco QoS features, including IP Precedence, RSVP, Weighted Fair Queuing (WFQ), Weighted Random Early Detection (WRED), and Multichassis Multilink PPP (MMP) fragmentation and interleaving, implemented on both the universal gateway and backbone routing infrastructure, can provide a low-latency, high-reliability path for sensitive voice traffic through today's networks.

Echo control is essential for packet-switched networks to carry voice traffic successfully. The Cisco AS5350XM Universal Gateway conforms to the voice tests of ITU-T Recommendation G.168 2002 for echo cancellation with a tail length up to 64 ms. An option to configure a tail length up to 128 ms is also available. Fixed and adaptive jitter buffering and comfort-noise generation further enhance voice quality. The Cisco AS5350XM also supports the enhanced measurements and call-specific debugs features in Cisco IOS Software. In addition, the user can set items such as IP-side attenuation down to the individual T1 or E1 voice port.

Voice Codecs
The Cisco AS5350XM Universal Gateway offers multiple codecs to meet interoperability, compression, and latency requirements for a variety of voice applications. The same number of calls is supported across all codec types to simplify network engineering. Enabling voice activity detection (VAD) reduces packet traffic through the network. With VAD enabled, the Cisco AS5350XM detects silence and stops transmitting packets when callers stop speaking. Variable frame sizing provides further control over speech packetization.

The Cisco AS5350XM Universal Gateway supports the following voice codecs:

For VoIP to be a practical replacement for standard PSTN telephony services, customers need to receive the same consistent, high quality of voice transmission they receive with basic telephone services. For real-time, delay-sensitive traffic such as voice, it is better to deny network access under congestion conditions than to allow traffic onto the network to be dropped and delayed, causing intermittent impaired QoS and resulting in customer dissatisfaction.

Numerous QoS mechanisms exist in Cisco IOS Software to allow service providers to design and configure packet networks that provide the necessary low latency and guaranteed delivery required for voice traffic. These mechanisms include tools such as queuing, policing, traffic shaping, packet marking, and fragmentation and interleaving.

Call admission control (CAC) extends the QoS tool suite to protect voice traffic from being negatively affected by other voice traffic, keeping excess voice traffic off the network. CAC allows the Cisco AS5350XM Universal Gateway to make deterministic and informed decisions before a voice call is established based on whether the required network resources are available to provide suitable QoS for the new call. CAC provides:

Voice Extensible Markup Language Solution Infrastructure
The Cisco AS5350XM Universal Gateway can interpret Voice Extensible Markup Language (VoiceXML) documents. VoiceXML is an open-standard markup language used to create voice-enabled Web browsers and interactive-voice-response (IVR) applications. Just as HTML enables users to retrieve data with a PC, VoiceXML enables subscribers to retrieve data with a telephone. The accessibility of the telephone and its ease of use make VoiceXML applications a powerful alternative to HTML for accessing the information and services that the Internet provides. The Cisco VoiceXML Solution Infrastructure takes advantage of Cisco AS5350XM Universal Gateway DSP resources, signaling, and media-conversion capabilities to execute VoiceXML application logic at the edge of the network, offloading servers and the network to support unified communications services. Cisco VoiceXML gateways support two standard audio formats for recording and playback: .au (audio/basic) and .wav (audio/wav). The VoiceXML Store and Forward feature allows streaming-based voice recording and playback features for various media, including local memory, HTTP, Extended Simple Mail Transfer Protocol (ESMTP), and Real-Time Streaming Protocol (RTSP) for 14 different Cisco codecs and the two standard audio file formats.

The Cisco AS5350XM Universal Gateway running a VoiceXML or TCL application can use Media Resource Control Protocol (MRCP) to control media resources on external media servers, such as speech synthesizers for text-to-speech (TTS) and speech recognizers for automatic speech recognition (ASR). MRCP is an application-level protocol developed by Cisco and its ASR and TTS media server partners, Nuance Communications and SpeechWorks International. The ability of this gateway to interact with ASR and TTS servers provides the capabilities required to satisfy the most demanding and advanced IVR solutions.

Programmable Tool Command Language IVR 2.0
Integrated, programmable IVR extends the ability of the Cisco AS5350XM Universal Gateway to support unique and differentiated voice services. Voice application software developers can use the Tool Command Language (TCL) IVR 2.0 application programming interface (API) to create customized TCL scripts that control calls coming into or going out of the gateway. IVR systems collect user input in response to recorded messages. The prompts used in a TCL IVR 2.0 script can be either static or dynamic. The scripts are event-driven, and call flow is controlled by a finite-state machine that is defined by the TCL script. All verbs are nonblocking-they can execute without causing the script to wait. Prompts can be played and digits can be collected over telephony or VoIP call legs. RTSP-based prompts are supported. TCL IVR 2.0 offers enhanced multilanguage support by providing the capability to add new languages and TTS notations to the core IVR infrastructure. The Cisco Developer Support program assists companies developing or modifying TCL IVR 2.0 scripts.

Unified Communications
Voicemail solutions are rapidly moving away from traditional TDM-based messaging solutions to a unified messaging architecture where subscribers can access messages from a variety of devices.

Unified communications uses the IP infrastructure to unify the communications methods that were previously disjointed-e-mail applications, fax machines, voicemail systems, cellular phones, and Web communications. This gives users a common method to both access messages and initiate real-time communications-all using familiar devices.

Service providers can implement unified communications solutions by deploying Cisco AS5350XM universal gateways between traditional PSTN or wireless networks and their packet-based telephony network and adding application servers that support unified communications services. Cisco has partnered with several industry-leading developers to provide unified communications solutions. Following are some of the cost-effective services that carriers can offer to build brand identity and increase customer loyalty while reducing turnover:

Fax Features
Fax transmission over an IP infrastructure is an important and growing service opportunity, especially in international markets where fax represents a large percentage of network traffic. The Cisco AS5350XM Universal Gateway supports standards-based T.38 Real-Time Fax Relay and T.37 Fax Store and Forward, allowing greater interoperability between networks. The fax detection capabilities of the Cisco AS5350XM Universal Gateway allow service providers to offer a single E.164 number for subscriber voice and fax services. Half as many subscriber phone numbers are needed, resulting in significant cost savings. The Cisco AS5350XM also supports fax pass-through for VoIP environments that cannot support T.38 Real-Time Fax Relay end to end. Enhanced T.38 Fax Relay statistics in the gateway RADIUS call accounting record provide detailed information about each fax call, including modulation rate, number of pages, packets transmitted and received, and a fax success indication.

Softswitch Interoperability
Softswitch products that support SIP, H.323, or MGCP can be used with the Cisco AS5350XM Universal Gateway to support advanced applications for broadband services. The Cisco BTS 10200 Softswitch and the Cisco PGW 2200 Softswitch are two of the many softswitch products that interoperate with the Cisco AS5350XM Universal Gateway.

SS7 Interconnect
Using the Cisco PGW 2200 PSTN Signaling Gateway (or a third-party SS7 gateway) and the Cisco AS5350XM Universal Gateway with integrated SLT functions, service providers can interconnect their data and VoIP networks with the PSTN through SS7 links. In many countries carriers must interconnect through SS7 to qualify for reciprocal compensation.

The Cisco PGW 2200 PSTN Signaling Gateway and Cisco AS5350XM Universal Gateway provide the interface needed for SS7 interconnect using ISDN User Adaptation Layer (IUA) with Stream Control Transmission Protocol (SCTP) as the call signaling IP transport mechanism, allowing service providers to enter markets previously unavailable to them because of signaling requirements. SS7 trunks are more efficient than CAS trunks, and they typically cost less than Primary Rate Interface (PRI) trunks. With SS7, call setup time decreases, increasing the amount of billable traffic carried by the network.

Integrated SLT
The Cisco AS5350XM Universal Gateway trunk cards also have serial interfaces for integrated SLT functions. With integrated SLT, the Cisco AS5350XM Universal Gateway provides distributed Message Transfer Part (MTP) SS7 signaling functions directly on the gateway. Like the Cisco 2600 Series-based SLT, the integrated SLT backhauls upper-layer SS7 protocols across an IP network using Cisco Reliable UDP (RUDP), terminating the MTP1 and MTP2 layers of the SS7 protocol stack. Integrated SLT support is available through a software upgrade-no new hardware is required. MTP3/ISUP backhaul is included. Pricing is on a per-platform basis.

TDM Switching
TDM switching is the ability to take an incoming call on a given DS-0 and send it out on a different DS-0 before the call is answered by the gateway. This feature is used in applications such as:

This feature typically does not require any DSP resource and hence has no impact on the voice, fax, or data-handling capability of the platform. TDM switching plus network-side ISDN functions provide a means of grooming incoming traffic and passing selected calls to external devices, such as private branch exchanges (PBXs), test sets, VoIP gateways, or access servers. The Cisco AS5350XM Universal Gateway can switch calls between SS7, PRI, and CAS trunks. TDM Switching of CAS calls requires DSP resources.

The Cisco AS5350XM Universal Gateway TDM backplane supports CT3-to-CT3 TDM switching in 1RU.

Remote-Access Capabilities
While still maintaining its capabilities as a best-of-breed voice gateway, the Cisco AS5350XM Universal Gateway takes advantage of the full-feature richness and strong routing capabilities of Cisco IOS Software. It can be deployed in various architectures, from multiprotocol corporate networks (IP, IPX, AppleTalk, and NetBEUI, for example) to service provider IP networks. In addition, the Cisco AS5350XM fully supports the specialized needs of AOL, MSN, and other content-oriented dialup services through PPP, Layer 2 Tunneling Protocol (L2TP), or Transmission Control Protocol Clear (TCP Clear) connections.

The Cisco AS5350XM Universal Gateway also supports the most complete set of access protocols of any access server in the industry, including PPP, IPX Control Protocol (IPXCP), AppleTalk Control Protocol (ATCP), AppleTalk Remote Access (ARA), NetBIOS Frame Control Protocol (NBFCP), NetBIOS over TCP/IP, NetBEUI over PPP, and protocol translation.

V.92 and V.44 Support
V.92 and V.44 are the latest modem standards adopted by the industry. The standards specify a set of features that allow modems to mimic many of the benefits of broadband:

Service providers can offer revenue-generating services and increase subscriber retention with V.92 and V.44 standards. Cisco RADIUS support for Modem on Hold allows premium subscribers to suspend their Internet sessions for longer periods of time to place or receive phone calls. Quick Connect saves the line conditions of the last number dialed, encouraging subscribers to dial into the same ISP to reduce connection time. Combined with greater compression and connection speeds, V.92 and V.44 allow service providers to offer their subscribers a "broadband-lite" experience, enabling Internet users to experience the qualities usually associated with broadband for the price of dialup or modem access.

Security Management
Cisco IOS Software security features allow authorized users dialup access while preventing access to intruders. These features include: multilevel password protection; user authentication such as Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP); access control lists (ACLs); IP address spoofing prevention and logging; support of the industry-standard authentication, authorization, and accounting (AAA) protocols; RADIUS; and TACACS+.

Internet Connectivity
Enterprises and service providers need to extend network access to a broad range of remote users, including employees, customers, and partners. Successful remote access means being able to connect these users from practically any location, almost transparently. The Cisco AS5350XM Universal Gateway, combined with Cisco IOS Software, meets these needs by extending the core infrastructure through secure, reliable dial-in connections.

Data Over Voice Bearer Service (DoVBS) is used in areas where ISDN data calls are charged at a higher rate (or tariff) than ISDN voice calls. The ISDN customer-premises-equipment (CPE) device (terminal adapter or router) must support DoVBS operation-most popular ISDN devices available today support DoVBS. The ISDN CPE device is programmed to signal all ISDN data calls as voice calls to ensure that these calls are billed at the lower voice rate. Cisco Resource Pool Management (RPM) on the Cisco AS5350XM Universal Gateway is used to configure a customer profile for DoVBS calls based on Digital Number Identification Service (DNIS). This profile configures the Cisco AS5350XM to treat all calls received on that number as ISDN data calls, even if they are signaled as voice calls by the PSTN network.

Wholesale Dial
Many ISPs and content providers (or "portals") must provide dialup Internet access as part of their service packages, and enterprise companies want to offer "private-label" Internet access to promote their brands. However, they do not have the experience, personnel, time, or money to build out a dialup access infrastructure, or they cannot build it fast enough-particularly when expanding into new regions. Service providers can now take advantage of this opportunity through the Cisco Wholesale Dial solution.

The Cisco Wholesale Dial outsourcing solution delivers "virtual port" capability across any number of Cisco remote-access servers. Coupled with third-party port policy management that guarantees port availability to wholesale customers, Cisco helps carriers and ISPs offer unique service offerings that increase incremental revenue while keeping operations costs low. The network infrastructure deployed for wholesale dialup also can be used to offer standard retail dialup services, plus other value-added services such as corporate dial outsourcing, Internet gaming, unified communications, VoIP, and VPNs.

Regional and Branch-Office Connectivity
The Cisco AS5350XM Universal Gateway is ideally suited for deployment in branch offices for providing remote access for telecommuters and mobile users. The CT1, CE1, and PRI interfaces can be used for remote access; the Ethernet ports can be used for LAN connectivity; and the serial ports can be used for access to the corporate site or to the Internet. Using the Enterprise Plus features of Cisco IOS Software, desktop protocols can be enabled.

Access VPNs
The Cisco AS5350XM Universal Gateway is ideally suited to providing wholesale dial services to both large corporations and ISPs that do not want to support their own dial pools. With Cisco IOS Software support for VPNs, service providers can take advantage of their existing infrastructures to deliver local dialup access for users of enterprise networks. By providing virtual dialup solutions, service providers can offer a full range of services closer to the remote user. Local calls can now be placed to gain access to the core infrastructures. Virtual dialup services attract more users of this service, and because calls are terminated locally, long-distance charges are eliminated and infrastructure costs are reduced.

VPN Provisioning and Accounting
OL Support
The importance to service providers in the VPN environment is the need to both provision andaccount for the number of connections that are allowed by VPN customers. Cisco Virtual Private Dialup Network (VPDN) session-counting software can keep track of the number of connections from the Cisco AS5350XM Universal Gateway to the user's home gateway. This software is provided in Cisco IOS Software running on the Cisco AS5350XM and in the Cisco access control server to provide comprehensive accounting and billing information to ISPs about the virtual connections that their customers make.

The Cisco AS5350XM Universal Gateway offers 100-percent coverage for dedicated AOL dial installations, as well as other services that use the TCP Clear or autocommand Telnet method of carrying dialup data. Domain Name System (DNS) round robin also is supported to allow load balancing of connections across multiple AOL hosts. The Cisco AS5350XM also includes all the L2TP features necessary to support clients with AOL 7.0 and later versions.

Manageability
The Cisco AS5350XM offers a wide range of open protocols to support management. The Simple Network management Protocol (SNMP) Versions 2 and 3 management capability includes a rich call-tracking SNMP MIB that provides highly detailed records for active and historical calls, with a configurable call-history buffer. Call records also can be obtained through syslog or RADIUS as an alternative to polling through SNMP. Call records include connect rate, connect duration, disconnect codes, end-to-end delay, and line statistics. Voice and dial service providers can use this performance-management data to establish service-level agreements with their customers.

The console-management features include a comprehensive set of debugging commands than can be enabled on a specific calling line ID (CLID) or automatic number identification (ANI), called number (DNIS), user, or interface to immediately isolate only the relevant debugging output.

CiscoWorks includes a plug-in to manage the Cisco AS5350XM Universal Gateway. The Cisco AS5350XM is also supported in the Universal Gateway Call Analyzer, a monitoring and troubleshooting application for Cisco AS5000 universal gateways deployed for dial services.

Universal DSPs
The Cisco ASAP architecture is based on universal DSP technology. The universal DSP can execute multiple codec and modem algorithms on any DSP at any time. When the type of codec or modem required for a specific call is determined, the DSP activates the appropriate service type in real time.

RELIABILITY
DSP Sparing and Pooling
The Cisco AS5350XM Universal Gateway is designed to meet high-availability requirements. The universal DSPs are pooled and can be configured as hot spares. Because DSPs are allocated on a call-by-call basis, a DSP failure does not cause a DS-0 or B channel to be left without a DSP to terminate the call. This prevents occurrence of "holes" (unused channels) within a hunt group. Having spare DSPs in the pool also allows DSP code to be updated without affecting active calls. DSP resources are tested at power-up and after disconnect to check for defects. Any defective DSPs found are moved to the resource recovery pool. An automatic DSP recovery process can be activated to recover DSPs in the recovery pool and add them back into the resource pool if possible.

Hot-Swappable Cards and Fan Tray
Hot-swap capability on all cards allows hardware maintenance to be performed on an active Cisco AS5350XM Universal Gateway with little or no service interruption. During a hot-swap, any card can be removed, inserted, or replaced, and only the calls on the card being removed are affected. The Cisco AS5350XM chassis provides five high-capacity fans with front-to-back airflow for cooling. The fan tray can be replaced while the unit is in operation.

Redundant Backhaul Methods
Three redundant methods that can be used to backhaul traffic from the server to the network are included by default on the Cisco AS5350XM Universal Gateway. The first method uses the two Gigabit Ethernet ports, which can be configured to run different types of traffic on each link for increased reliability. The second method uses the two high-speed, 12-in-1, 8-Mbps serial ports. These ports support all the Cisco serial routing protocols for flexibility in connecting to remote networks. The third method uses trunk feature cards as possible backhaul interfaces.

Environmental Monitoring
Thermal sensors monitor the inlet and outlet temperatures and temperature rise across each card. If the operating temperature of the system exceeds its maximum, the thermal sensors initiate a shutdown of the feature cards, starting with the DSP cards and finishing with the trunk cards. The trunk cards are shut down last so the system has a chance to recover before putting the trunks into alarm status at the central office. If the system continues to exceed its maximum operating temperature, the thermal sensors initiate a shutdown, preventing damage to the unit or its surrounding environment from excess heat.

The Cisco AS5350XM Universal Gateway offers the option of a redundant power supply or single power supply. The redundant power system comprises a fully redundant switching power supply with two AC (or two DC) inputs to the main power modules. Each input and output is 100-percent fully redundant, with dual fans for added reliability and mean time between failure (MTBF) of more than 200,000 hours. The single AC or DC power supply also has dual fans for added reliability and a MTBF of more than 200,000 hours. Both the redundant and single power supplies have internal protection features: overcurrent, overvoltage, and thermal shutdown. Internal sensors to the power supplies monitor all operational parameters, and alarm status is provided to the system.

Regulatory Compliance
The Cisco AS5350XM Universal Gateway complies with Network Equipment Building Standards (NEBS) Level 3 requirements, as defined by Telcordia SR-3580, and also complies with European requirements as defined by the ETSI.

Multivendor Back-Office Integration
The Cisco AS5350XM Universal Gateway supports RADIUS and TACACS+ protocols for back-office integration, control, and security. In addition to supporting the IETF-defined RADIUS attributes, Cisco IOS Software supports many vendor-specific RADIUS attributes for preauthentication, user authentication, and call accounting. This means that the Cisco AS5350XM can be integrated into any multivendor remote-access and voice network with no changes to the back-office systems.