Cisco 5814 Dial Shelf

The first time a router shelf sends an inventory response to the DSC, it includes a flag indicating that all dial shelf cards should be reloaded. In split mode, the final dial shelf card image is downloaded by each DSC from the router shelf that owns it.

Slot Ownership Arbitration

The DSCs communicate between themselves to determine which one is to be active, where “being active” implies being the master for all the dial shelf card slots. In split mode, each DSC is the master for the set of dial shelf cards in the slots owned by its connected router. Additional messages indicate when DSCs are in split mode and what set of slots they control.

A DSC that is already in split mode simply advertises that it is in split mode and which slots it is claiming. When a second DSC receives an indication that the first DSC is in split mode, its behavior depends on the current configuration of its attached router.

•If the attached router is not configured for split mode, the second DSC sends error messages to its connected router and indicates its router’s state to the first DSC. The first DSC issues the same error messages to its router.

•If one attached router is configured in split mode and the other is in normal mode, the router that is in normal mode stops claiming ownership of any slots and does not respond to boot requests from any of the dial shelf cards. The router that is in split mode responds to boot requests only from dial shelf cards in the slots that it owns. However, it does not take over (restart) the dial shelf cards in its slots until the normal mode router is removed or is also configured in split mode.

Hub Redundancy

In normal mode, both DSCs are connected to the same router shelf. The active DSC monitors the status of its link to the router shelf and, in the event of link failure, requests the other DSC to take over. When operating in split mode, each DSC is connected to a different router shelf, so the DSCs do not send or respond to link failure messages. If one DSC’s link fails, the other DSC cannot transparently take over.

TDM Resource Allocation

Trunk cards and modem cards are tied together across a time-division multiplexing (TDM) bus on the dial shelf backplane. Time slots for the TDM bus are allocated by the router shelf on a call-by-call basis. This is implemented by initializing a queue at start up with one element for each usable time slot (currently 14*128 = 1,792 time slots are used). Time slots for a call are allocated from the front of the queue and replaced at the end of the queue when the call is completed. For split dial shelf operation, time slots are added to the queue dynamically, as they are needed. When a TDM slot is required and the queue is empty, a chunk of TDM slots is allocated to the queue.

In normal mode, the router shelf connected to the DSC in slot 12 allocates time slots starting from 0 going up, and the router shelf connected to the DSC in slot 13 allocates time slots starting from 1,791 going down. For split dial shelf operation each router is assigned half of the usable set of time slots. The router shelf connected to the DSC in slot 12 controls the first half of the time slots (0 to 895). The router shelf connected to the DSC in slot 13 controls the second half of the time slots (896 to 1791).

Cisco AS5800 Product Overview 1-11

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Cisco Systems AS5800 manual Slot Ownership Arbitration, Hub Redundancy, TDM Resource Allocation
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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.
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