Glossary

FIFO—First-in, first-out. In data communication, FIFO refers to a buffering scheme where the first byte of data entering the buffer is the first byte retrieved by the CPU. In telephony, FIFO refers to a queuing scheme where the first calls received are the first calls processed.

Gatekeeper—A gatekeeper maintains a registry of devices in the multimedia network. The devices register with the gatekeeper at startup, and request admission to a call from the gatekeeper.

The gatekeeper is an H.323 entity on the LAN that provides address translation and control access to the LAN for H.323 terminals and gateways. The gatekeeper may provide other services to the H.323 terminals and gateways, such as bandwidth management and locating gateways.

Gateway—A gateway allows H.323 terminals to communicate with non-H.323 terminals by converting protocols. A gateway is the point at which a circuit-switched call is encoded and repackaged into IP packets.

An H.323 gateway is an endpoint on the LAN that provides real-time two-way communications between H.323 terminals on the LAN and other ITU-T terminals in the WAN, or to another H.323 gateway.

H.323—An International Telecommunication Union (ITU-T) standard that describes packet-based video, audio, and data conferencing. H.323 is an umbrella standard that describes the architecture of the conferencing system, and refers to a set of other standards (H.245, H.225.0, and Q.931) to describe its actual protocol.

H.323 RAS—Registration, admission, and status. The RAS signaling function performs registration, admissions, bandwidth changes, status and disengage procedures between the VoIP gateway and the gatekeeper.

HSRP—Hot Standby Routing Protocol. HSRP is a Cisco proprietary protocol which provides a redundancy mechanism when more than one router is connected to the same segment/subnet of an Ethernet/FDDI/Token Ring network.

ISDN—Integrated Services Digital Network. ISDN is a communications protocol, offered by telephone companies, that permits telephone networks to carry data, voice, and other traffic.

ITU-T—Telecommunication standardization sector of ITU.

IVR—Integrated voice response. A software feature that allows the use of one of several interactive voice response scripts during the call processing functionality.

LEC—Local exchange carrier.

LRQ—Location request.

MCU—Multipoint control unit

mu-law—a-law—A voice compression technique commonly used in North America.

Multicast—A process of transmitting PDUs from one source to many destinations. The actual mechanism (that is, IP multicast, multi-unicast, etc.) for this process may be different for LAN technologies.

Multilink PPP—Multilink Point-to-Point Protocol. This protocol is a method of splitting, recombining, and sequencing datagrams across multiple logical data links.

Multipoint-unicast—A process of transferring Protocol Data Units (PDUs) where an endpoint sends more than one copy of a media stream to different endpoints. This may be necessary in networks which do not support multicast.

node—An H.323 entity that uses RAS to communicate with the gatekeeper. For example, an endpoint such as a terminal, proxy, or gateway.

PDU—Protocol Data Units. Used by bridges to transfer connectivity information.

Voice over IP for the Cisco AS5800 73

AS5800 specifications

Cisco Systems has long been a leader in the networking and telecommunications field, and its AS5800 series of routers exemplify this tradition. The AS5800, along with the AS5850, AS5350, AS5400, and AS5300, provides robust solutions for service providers and enterprise-level networking applications. Each of these models has distinct features and characteristics that cater to the evolving demands of internet traffic and data processing.

The Cisco AS5800 is designed for high-capacity routing and optimized for broadband services. It supports a wide range of services, including voice, data, and video applications, making it a versatile option for service providers looking to deliver integrated solutions. It is equipped with advanced quality of service (QoS) features that ensure bandwidth is allocated effectively, holding strong even under heavy traffic conditions.

In comparison, the AS5850 offers superior processing capabilities and is typically utilized in larger-scale implementations. This model supports high-density interfaces, allowing numerous connections without compromising performance. Its architecture includes enhanced MPLS (Multiprotocol Label Switching) support, enabling more efficient traffic management and better utilization of network resources.

The AS5350 is known for its scalability and energy efficiency, ideal for voice-over-IP (VoIP) and media gateway applications. It supports various telephony features, such as protocol interworking and transcoding, making it a preferred choice for organizations focusing on digital voice technologies. The AS5300, while slightly older, continues to be a valuable asset for less demanding networks, offering reliable performance with VoIP capabilities and basic data applications.

The AS5400 bridges the gap between high-performance routing and operational efficiency. It incorporates Cisco's proprietary technologies to ensure seamless connectivity and robust failover systems. This model is highly regarded for its security features, protecting network integrity and providing peace of mind for businesses relying on sensitive data transfer.

Overall, Cisco’s AS5800 series showcases a progressive evolution of routing capabilities with enhanced features tailored for resilience, scalability, and performance. These routers not only address the technical needs of modern networks but also strategically position organizations for future growth in an increasingly digital world. Each model, with its unique attributes, continues to support the varied demands of global communication infrastructures.