The Cisco® ASR 901S Series Aggregation Services Routers are optimized for the backhaul of true multivendor heterogeneous small cell networks. As mobile operators seek to aggressively deploy small cell networks in an effort to increase capacity and coverage, they will be challenged to do so without straining their capital and operational budgets. The ASR 901S Series is designed specifically to ease these constraints and enable the wide-scale deployment of small-cell networks. The ASR 901S routers are compact, environmentally hardened, low-power-consumption routers that can be installed in the outside plant, without an enclosure. The routers can be easily deployed in challenging locations such as on lampposts, telephone poles, and sides of walls. By using the Cisco ASR 901S, operators can reduce backhaul operating costs, simplify deployment and provisioning, and enhance their profit opportunities with premium mobile and Ethernet services.
To successfully implement a small cell network requires far more cell sites than in macro networks, and thus significantly more backhaul links. While small cell networks will inevitably become a reality, service providers are challenged to create an affordable, customized, and flexible backhaul environment that addresses this wide-scale network deployment. A critical requirement is that the small cells must be small enough to mount in challenging low-profile environments such as lampposts. A significant issue is effectively and efficiently delivering sufficient bandwidth to each of these locations. While small cell backhaul routers require functions similar to those of existing cell-site routers for macro radios, they do have very distinct mechanical requirements to support outdoor deployments. The Cisco ASR 901S is designed to meet service provider requirements for flexible, scalable, and cost-optimized small cell backhaul networks.
This ASR 901S platform provides unique Cisco value to the small cell backhaul market:
Flexible architecture that supports true multivendor "any-G" heterogeneous radio technology and backhaul topologies
Dramatically reduced operating expenses (OpEx) and TCO through zero-touch provisioning (ZTP) capabilities and extensive management tools
Unsurpassed user experiences through Cisco's best-in-class routing and comprehensive operations, administration, and maintenance (OAM) capabilities
The Cisco ASR 901S Series is family of small cell routers designed to support backhaul in deployment of small cell radios. The ASR 901S routers are small-form-factor, environmentally hardened (IP65 rated), low power, and cost effective. They complement the Cisco ASR 901 as part of the Cisco end-to-end mobile backhaul solution and transparently integrate into existing operational environments. A Cisco ASR 901S router prioritizes and processes small cell-site voice, data, and signaling traffic as part of the Cisco Unified RAN Backhaul solution for reliable transport across any available backhaul networks.
Designed for small cell sites in outdoor deployments, the Cisco ASR 901S features include:
Simplified deployment: ZTP, including circuit validation, and extensive management tools to reduce OpEx and TCO
Wireless management (Wi-Fi) interface to minimize physical access to the unit, helping reduce the network maintenance costs
Complementarity to the ASR 901 as part of the Cisco Unified RAN Backhaul solution (same features as the ASR 901 to give the customer consistent deployment across macro and small cell backhaul with a common operational environment)
Full support for Layer 2, Layer 3, and Multiprotocol Label Switching (MPLS) deployment models
Comprehensive OAM capability, Connectivity Fault Management (CFM), Y1731 FM/PM and Y.1564 compliance, and service loopback
Proven interoperability with multiple microwave vendors
IP65 compliant, compact, aesthetically pleasing enclosure designed for outdoor deployments and designed to work at -40 C to 65° C (-40 F to 149° F) ambient temperatures.
Flexible options for different combinations of copper and Small Form-Factor Pluggable (SFP) 1-G ports
Mechanical mounting options to enable mounting on brackets, walls, lampposts, etc.
Maximum power consumption < 40W without Power over Ethernet Plus (PoE+)
Support for POE+ on the copper ports in the AC variant
Completely fanless passive cooling design
Figure 1.Cisco ASR 901S Front, Back, and Bottom Views
The mechanical design of ASR 901S is IP-65 compliant with fanless passive cooling.
• The front side of the chassis has two sections:
– The upper section is fixed and sealed. It cannot be opened in the field. Internally, this section houses the electrical circuitry.
– The lower section has a door that can be opened in the field. Opening this door gives users access to the port interfaces and enables them to service the ports (for example, changing the optical modules and cables).
• The cable bay is located in the lower part of the chassis. This space is used to route and fix the cables to the front panel as well as the power entry.
• The power entry on the right end is through an IP-65 compliant gland for DC. An ordinary DC cable runs through the gland. For AC inputs, a special IP-65 compliant connector system is used. The AC input cable can be removed from the system without opening the door.
• Each SFP port has a (LC-LC) patch cable from the SFP module to the front panel. For external connectivity, an LC cable system with IP-65 sealing is used.
• The alarm, management, and console port cat-5e cable is routed through the 4-wire gland.
• ASR 901S has conduction-cooled fanless design. The bottom part of the chassis acts as the heat sink for all the components.
• Field technicians can press a physical button on the chassis to reset the router and initiate zero-touch provisioning
Features and Benefits
Small Cell-Site Backhaul for Mobile Applications
Deployed as small cell backhaul routers for a mobile network, the Cisco ASR 901S routers can aggregate multiple small cells through Ethernet and IP interfaces, and can use MPLS, Resilient Ethernet Protocol (REP), Layer 2 VPN (L2VPN), Layer 3 VPN (L3VPN), and other common transport protocols for RAN backhaul. The ASR 901S prioritizes, differentiates, and segments any combination of second-, third-, or fourth-generation (2G, 3G, or 4G) traffic for backhaul over any combination of IP or Ethernet infrastructures (copper, microwave, or optical).
The exponential growth in mobile data traffic introduced the need for heterogeneous network deployments. With heterogeneous networks, the coverage area of a macro cell is enhanced by adding base stations with shorter coverage to handle some of the traffic of the macro cells. These short-coverage base stations are collectively called small cell base stations and can be categorized according to cell coverage and capacity as micro-, pico- and femtocells. Some of the traffic is offloaded to the small cells, improving the overall system performance with more evenly distributed traffic volumes, providing better and faster service for mobile clients (Fig. 2) .
Fig 2. Small Cell Backhaul Network Architecture Diagram
The Cisco ASR 901S helps service providers deliver advanced services and reduce operating costs for small cell mobile backhaul. Highlights include the following.
Low Total Cost of Ownership
Orders of magnitude more small cells than macro cells burden the old way of deploying wireless networks and strain capital and operational budgets. The ASR 901S helps operators to reduce TCO by simplifying the network deployment through ZTP and extensive management tools. ZTP features such as circuit validation make a large difference in bulk deployments. Field technicians need only mount the router, hook up power and cables in easily accessible ports, then press one physical button to reset the router and initiate zero touch provisioning. The Wi-Fi wireless management allows operators to monitor, configure, and troubleshoot the router without physical attachment, providing convenience for network maintenance and reducing operational expenses. POE+ support on AC models can power wireless backhaul devices that reduce the number of power connections needed at deployment sites.
The Cisco ASR 901S also helps service providers to reduce operating costs by optimizing energy efficiency, allowing cost-effective and responsible resource management. The routers are designed for low power consumption with Reduction of Hazardous Substances (RoHS) compliant, lead-free components. An indirect benefit is a significant reduction of carbon emissions.
"Zero Footprint" Deployment
With the ASR 901S, operators can deploy backhaul equipment along with small cell enclosures in harsh outdoor environments. The ASR 901S sealed enclosure can be mounted on lampposts, telephone poles, sides of buildings, H-frames, and in cabinets or vaults. The ASR 901S packaging is IP65 compliant and has a fanless passive cooling design, which makes it best suited for outdoor deployments. The ASR 901S portfolio provides port flexibility with various combinations of 1-G copper and SFP ports.
With the Cisco ASR 901S, services can be prioritized and differentiated through hierarchical quality of service (HQoS) and security attributes. The ASR 901S offers advanced traffic analytics and performance monitoring and control, including per-traffic-class metering, bidirectional packets, and byte statistics. The service offering is enhanced with comprehensive OAM functionality, including Layer 2 CFM, IP service-level agreements (SLAs) for Layer 3, and MPLS OAM.
The Cisco ASR 901S delivers line-rate performance and flexible service scalability in a compact form factor. With support for up to 32,000 MAC addresses, up to 4000 bridge domains, and multiple hierarchical queues, the router delivers high performance and scale for all mobile and Carrier Ethernet services.
The Cisco ASR 901S provides the timing services required in today's converged access networks by offering integrated support for the Synchronous Ethernet (SyncE) and 1588v2 standards.
Cisco network virtualization (nV) technology can simplify network operations by reducing the number of components that must be managed, supporting easier configuration. The result is increased network scalability, improved service velocity, and lower operating costs. The nV-capable Cisco ASR 901S routers can be deployed as satellites of a Cisco ASR 9000 Series system to reduce the complexity of today's mobile Internet networks.
Components and Options
Table 1 lists the hardware parts available for the Cisco ASR 901S Series.
Table 1. Chassis Models for the Cisco ASR 901S Series
4 external ports (4 SFP) + 1 gland interface for internal ports (2 Cu) , DC power supply unit (PSU)
• MPLS: MPLS using Label Distribution Protocol (LDP), EoMPLS, L3VPN, MPLS OAM, pseudowire redundancy, TE FRR, Labeled BGP (RFC3107)
• EOAM: CFM over pseudowire, IP SLA (LSP)
Flexible Software Options
The Cisco ASR 901S supports the Cisco IOS Software Activation feature. With this feature, Cisco IOS Software feature sets can be activated by Cisco software licenses, providing a "pay as services grow" model. This model allows service providers to invest in software resources only when their businesses need it. The Cisco ASR 901S offers two Cisco IOS Software feature licenses. Each license enables feature activation on a per-chassis basis.
• The Base license includes support for Layer 2 and Layer 3 features, Sync-E, and 1588 Ordinary Clock.
• The Advanced IP Metro license adds the following capabilities to the Base license: MPLS, MPLS VPN support, Ethernet pseudowires, and pseudowire redundancy.
Table 4 lists the main features in the Cisco IOS Software licenses for the Cisco ASR 901S.
Table 4. Software Feature Set in Cisco ASR 901S Licenses
Base Software Services (Default Image)
Advanced Metro IP Services
EVC infrastructure, 802.1Q, 802.1ad, QinQ, 802.3ah, and REP
All features in Base license plus the following
QoS, with deep buffers and hierarchical QoS
MPLS (LDP VPN), Labeled BGP (RFC3107)
Layer 2: 802.1d, 802.1q, Link aggregation
IP routing (BGP, OSPF, IS-IS, static routes), BFD, Multi-Hop BFD,VRF-lite
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