The Cisco® Carrier Routing System (CRS) offers industry-leading performance, advanced services intelligence, environmentally conscious design, and system longevity. The Cisco CRS is powered by the Cisco QuantumFlow Array™, a chipset architecture based on multidimensional engineering and Cisco IOS® XR Software, a unique self-healing, distributed operating system.
The increasing demand for bandwidth, propelled by new devices, cloud technologies, machine-to-machine communication, and media-rich applications, presents a capacity challenge in core networks. Expanding the core capacity with the Cisco CRS is a transparent, cost-effective process. Built for the next generation of Internet technologies, the Cisco CRS delivers continuous, always-on operations, capable of scaling from a single-chassis deployment into a massive multichassis system.
Scaling from a single-chassis to a multichassis system allows service providers to expand their network without increasing the complexity of their routing architectures. A A Cisco CRS multichassis system consists of two major elements: a Line Card Chassis (LCC) and a Fabric Card Chassis (FCC). The LCC hosts Performer Route Processor (PRP) cards, the first and third stage of switch fabric cards, and line cards that provide the physical interface and process data packets. The FCC hosts the second stage of the switch fabric cards. The LCC and FCC are connected by a set of optical cables. Expanding your core network capacity is a smooth process for the Cisco CRS, supported by in-service hardware and software upgrades.
Figure 1. Cisco CRS Back-to-Back (2+0) System
Increasing network capacity can be done in incremental steps. A Cisco CRS 16-Slot back-to-back system (Figure 1) allows customers to double network capacity without the need for a Fabric Card Chassis to handle the multidirectional data flow. A back-to-back system is also called a 2+0 system because it includes two LCCs and zero FCCs. A CRS back-to-back multichassis system provides the same capacity and functionality as a traditional 2+1 multichassis deployment (two LCCs and one FCC). The 2+0 back-to-back system has all the benefits of a 2+1 multichassis system while mitigating CapEx and OpEx by eliminating the immediate need for an FCC. Pairing two LCCs to create a CRS back-to-back system does not require any dedicated slots for interconnection; switch fabric cards and optical cables connect the chassis to form a single logical system that maintains full bandwidth between chassis. The system does not require topology changes, providing a smooth, uninterrupted path for expanding to a full-scale multichassis system. The 2+0 back-to-back system can be transparently migrated to a full-scale multichassis system while in service by adding a Cisco CRS FCC and up to eight additional CRS LCCs.
The flexible and scalable design of the Cisco CRS is used for handling all types of deployment scenarios, scaling from single-chassis deployments to massive multichassis systems. The CRS multichassis system supports configurations from 2+1 up to 9+1, as well as the 2+0 configuration. Table 1 shows how the CRS scales from a single chassis to a multichassis system.
Table 1. Cisco CRS Multichassis Scaling Options
CRS 16-Slot 2+0 Back to Back
CRS 16-Slot X+1 Multichassis
(X = 3 to 9)
Chassis compatibility (product part numbers)
Aggregate switching capacity
Up to 322 Tbps
Number of forwarding slots
Up to 1152
A Cisco CRS multichassis system provides the following advantages:
• Expands the network capacity without increasing the complexity of network and routing architectures
• Supports in-service migration from a single chassis to a back-to-back system to a full-scale multichassis system
• Supports a mix of 40-GE and 140-GE line card chassis in a single system
• Supports a mix of 40-GE and 140-GE line cards in single line card chassis
• Backwards compatible with both the CRS-16/S and CRS-16/S-B chassis
Expanding a Single Chassis to a Back-to-Back System
Upgrading to a Cisco CRS back-to-back system requires two components: the conversion kit and an additional 16-slot LCC. The conversion kit includes S13 fabric cards (which replace the S123 cards) and rear cable management. The additional 16-slot LCC should include a complete chassis system (LCC) with S13 switch fabric cards and with the necessary cables to connect the two LCCs. Product part numbers and descriptions are listed in Table 2.
Table 2. Components for Upgrading a Single Chassis to a Back-to-Back System
Product Part Number
Second chassis with back-to-back cables
Eight S13 fabric cards for the single-chassis upgrade
Rear cable management if the single chassis is CRS-16/S
Rear cable management if the single chassis is CRS-16/S-B
Optional: needed only if single chassis is using CRS-16-RP-B
Expanding to a Full Multichassis System
To expand from a single chassis or back-to-back system, a Fabric Card Chassis is needed for interconnections to multiple Cisco CRS 16-slot systems. The interconnectivity of FCCs and Cisco CRS 16-slot systems allows the Cisco CRS to gracefully scale from 4.48 to 322 Tbps of system capacity. The key components for upgrading to a full-scale multichassis system are shown in Table 3.
Table 3. Components for Upgrading to a Full Multichassis System
Product Part Number
Product Name and Description
3 to 9
Cisco CRS 16-Slot Single-Shelf System
Cisco CRS 16-Slot Single-Shelf System Enhanced
CRS-3 Multichassis System with 24-Slot Fabric Chassis
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For More Information
For more information about the Cisco CRS product family, contact your local account representative or visit Cisco at: http://www.cisco.com/go/crs.