The Cisco® ASR 1000 Series Aggregation Services Router is the next-generation, modular, highly services-integrated Cisco routing platform designed with the flexibility to support a wide range of 4- to 16-Mpps packet-forwarding capabilities, 5- to 20-Gbps system bandwidths performance, and scaling. The overall system architecture is common across the chassis. With the Cisco ASR 1000 Series, Cisco is creating an entirely new price-for-performance class with an innovative set of capabilities to respond to changes that are converging within the service provider and enterprise networks: video, Web 2.0, collaborative applications, and emerging requirements, all of which require a different type of edge device.
This document introduces this new router series; it does not address the details of platform hardware and software architectures nor the various available feature sets.
System Innovations
Cisco ASR 1000 Series Routers bring many innovations to the routing industry; some of the most notable ones follow:
• Extremely modular, flexible, and integrated design for meeting changing requirements in today's networks
• First revolutionary Cisco QuantumFlow Processor (QFP)
• Cisco QuantumFlow Processor-based platform that facilitates various services up to 20 Gbps
• True carrier-class system from the beginning, with In Service Software Upgrade (ISSU) that offers nonstop router operation
• Complete logical and physical separation of system routing, forwarding, and I/O planes, resulting in a highly robust system that is flexible to meet always-increasing performance needs
• Software modularity to minimize the effects of software upgrades in the system and lower operating expenses (OpEx)
• Highly sophisticated system software and hardware design to boost application availability, even during system oversubscription
• Lights-out remote-management facility: The Cisco ASR 1000 Series Route Processor remains accessible through a console Ethernet management port, even during Cisco IOS® Software failure.
• Investment protection: These routers reuse the investment made in network I/O by using Cisco shared port adapter (SPAs).
Cisco ASR 1000 Series Router Overview
The Cisco ASR 1000 Series Router is intended to address the performance gap between Cisco 7200 and Cisco 7600 Routers. The Cisco ASR 1000 Series is fully modular, from both hardware and software perspectives, and the routers have all the elements of a true carrier-class routing product serving both enterprise and service provider networks.
The Cisco ASR 1000 Series includes various packaging options differentiated by the number of I/O slots, capacity, redundancy, and power. A common hardware and software architecture and common components are used across these new router platforms to support the various modular and nonmodular chassis configurations (ranging from 2 to 6 rack units [RUs]). The following chassis options are available:
• Cisco ASR 1002 Router (2RU chassis with modular Cisco ASR 1000 Series Embedded Services Processor [ESP], fixed Cisco ASR 1000 Series Route Processor, and fixed Cisco ASR 1000 Series SPA Interface Processor [SIP] with 4 built-in Gigabit Ethernet ports)
• Cisco ASR 1004 Router (4RU chassis with modular ESP, route processor, and SIPs)
• Cisco ASR 1006 Router (6RU chassis with modular and redundant ESPs, route processor, and SIPs for SPA connectivity)
Three types of ESPs are available, a 5-Gbps ESP (ESP5; part number ASR1000-ESP5), a 10-Gbps ESP (ESP10, part number ASR1000-ESP10), and a 20-Gbps ESP (ESP20, part number ASR1000-ESP20), providing 5, 10, and 20 Gbps of system bandwidths, respectively.
The performance and scaling of Cisco ASR 1000 Series Routers for a forwarding plane-bounded feature are dictated by the capability of the central forwarding engine of the router in the form of an ESP card. Different ESP options are provided for all the chassis to offer you cost, performance, and scaling choices.
For enterprises, Cisco ASR 1000 Series Routers are intended as the midsize aggregation and gateway product typically residing in a regional WAN or WAN edge or large branch office and providing throughput in the 5- to 20-Gbps range with various services turned on.
For service providers, it is intended as the midrange service provider edge and Broadband Remote Access Server aggregation device with similar throughput.
High-Level System Architecture
You can partition the Cisco ASR 1000 Series Routers from a very high level into three elements: network control (route processor), data-plane forwarding (ESP), and network I/O (SIP).
One of the main differentiators of the platform is the logical and physical isolation of these planes in the system for nonstop operation and various types of resilience. For example, the routing plane is completely isolated from the forwarding plane (in fact, they are separate cards), hence loading of one does not affect the other.
Figure 1 shows the Cisco ASR 1006 Aggregation Services Router with dual route processors, dual ESPs, and three SIPs.
Figure 1. Cisco ASR 1006 Router System with Dual Route Processors, Dual ESPs, and Three SIPs
Route Processor
The route processor is based on a modern PowerPC CPU subsystem running Cisco IOS Software and platform-specific code, including the Cisco IOS XE Software. The route processor manages the following types of traffic:
• Management traffic coming through the Gigabit Ethernet management port on the route processor
• Punt traffic in the system (through the ESP), which includes all control-plane traffic received on any SPAs
• Older protocol traffic, DECnet, Internet Packet Exchange (IPX), etc.
In addition, the route processor is responsible for the chassis management, including activation and initialization of the other cards, selection and switchover of active vs. standby cards, image management and distribution, logging facilities, distribution of user-configuration information, and alarm control.
The route processor houses the console, auxiliary console, two universal-serial-bus (USB) ports, bootflash, hard disk drive (HDD), Building Integrated Timing Source (BITS) reference clock input (RJ-45), and the Gigabit Ethernet management port. The HDD does not participate in system operation; rather it is used to store core dumps, logging data, and OS binaries. Hence, booting the OS is not allowed from the HDD-that is facilitated in the system by means of bootflash and USB storage. By default, the modular route processor on the Cisco ASR 1004 and ASR 1006 model routers comes with 1 GB of embedded USB (eUSB; bootflash and nonvolatile RAM [NVRAM]), and a 40-GB hard drive for mass storage. The built-in route processor on the Cisco ASR 1002 Router comes with 8-GB eUSB, where 1 GB is for bootflash and 7 GB are for mass storage.
Embedded Services Processor
The ESP provides the centralized forwarding engine responsible for most of the data-plane processing tasks. All network traffic through the Cisco ASR 1000 Series Router flows through the ESP. It performs all the traditional baseline router packet operations, including MAC classification, Layer 2 and the various Layer 3 forwarding protocols, quality-of- service (QoS) classification, policing, shaping, load balancing, security access control lists (ACLs), VPN, and NetFlow.
The ESP executes more complex features such as firewalls, Network Based Application Recognition (NBAR), Network Address Translation (NAT), Flexible Packet Matching (FPM), numerous tunneling protocols, cryptography, and header and payload compression. It also performs the egress-packet buffering, queuing, and scheduling functions for the system.
The ESP, at a high level, can be divided into two subsystems:
• Cisco QuantumFlow Processor
• Control processor and other related circuitry
The Cisco QuantumFlow Processor is really the foundation of the Cisco ASR 1000 Series Router platform; it can be further divided into two blocks, the Cisco QuantumFlow Processor Engine and Cisco QuantumFlow Processor Traffic Manager subsystems. The engine is where all the Cisco IOS Software feature processing takes place, whereas the traffic manager performs various QoS features for both transit traffic and the traffic destined to the router.
The Cisco QuantumFlow Processor is the Cisco in-house, custom-built network processor that truly sets a new benchmark for data forwarding at tens of gigabit rates with various services configured. The processor includes 40 multithreaded packet-processing cores along with a buffering, queuing, and scheduling subsystem (the traffic manager) to perform buffering and scheduling at wire speed.
The Cisco QuantumFlow Processor is the industry's first fully integrated and programmable router chip designed to unify massive parallel processing, integrated QoS, and advanced memory management-while at the same time offering integral service delivery and programmability.
Figures 2 and 3 show the Cisco ASR 1000 Series system architecture.
Figure 2. Cisco ASR 1000 Series System Architecture: Distributed Control
Figure 3. Cisco ASR 1000 Series System Architecture: Centralized Data
As shown in Figure 3, ESP-to-ESP failover results in minimal data interruption (<50 ms), whereas route processor-to-route processor failover (also <50 ms) results in no data interruption at all.
SPA Interface Processor
The Cisco ASR 1000 Series SIP, unlike the SIPs for the Cisco 7600 Router and Cisco Catalyst® 6500 Switch, does not participate in packet forwarding; it is the housing for the SPAs in the system. Each SIP can take up to 4 half-height SPAs, 2 full-height SPAs, or a combination.
The SIP also provides packet prioritization for ingress packets from the SPAs and a large ingress burst absorption buffer for ingress packets awaiting transfer to the ESP for processing. The egress buffering is centralized on the traffic manager and also provided in the form of egress queues on the SIP.
The Cisco ASR 1000 Series Routers can prioritize traffic not only at the ESP level, but also throughout the system by configuring ingress and egress classification. Buffering (ingress and egress) coupled with back pressure to and from the ESP is provided in the system to deal with oversubscription.
The Cisco ASR 1000 Series Routers can be oversubscribed and considered a valid configuration, unlike Cisco 7200VXR Series Routers, where bandwidth points are enforced to avoid any possible oversubscription.
The Cisco ASR 1000 Series SIP also houses its own control processor to run various managers on the card, including the SPA drivers. Each SPA bay runs its own SPA driver, resulting in a completely hitless (to other SPAs in the same SIP, or other SIPs) ISSU for the SPA drivers in the system in case of upgrade or downgrade.
Shared Port Adapter
SPAs used in Cisco ASR 1000 Series Routers are the same SPAs as those used in the Cisco 7600, Cisco Catalyst 6500, Cisco gigabit switch routers (GSRs), and the Cisco CRS-1 Carrier Routing System. Hence, Cisco ASR 1000 Series Routers extend the value and investment protection for the network I/O in the form of SPAs.
Following is the complete list of SPAs that are supported with Cisco IOS XE Software Release 2.2 on the Cisco ASR 1000 Series Routers:
• 8-port Gigabit Ethernet
• 1-port 10 Gigabit Ethernet
• 2- and 5-port Gigabit Ethernet and 10-port Gigabit Ethernet
• 4- and 8-port Fast Ethernet
• 8-port T1/E1
• 2- and 4-port T3/E3
• 2- and 4-port OC-3/STM-1 Packet over SONET/SDH (PoS)
• 1-port OC-12/STM-4 PoS
• 2- and 4-port Channelized T3
• 4-port Serial (12-in-1)
• 1-port Channelized STM-1
• 2- and 4-port OC-48 PoS/Resilient Packet Ring (RPR) (PoS mode only)
Further SPA support will come in later software releases.
Cisco ASR 1000 Series Software Architecture
The Cisco ASR 1000 Series Router design is based around a distributed control plane to add another level of resilience in the system. A separate control processor is included on each major component of the router system (route processor, ESP, and SIP) that manages the local resources and data structures.
The various processors in the platform have the following basic roles:
• Route processor:
– Runs the router control plane (Cisco IOS Software), including processing of network control packets, computation of routes, and connection setup
– Manages ports and indicators, command-line interface (CLI), alarms, and network
– Downloads code to other components in the system
– Performs active route-processor and ESP selection and standby synchronization
– Performs logging facilities, onboard failure logging, and statistics aggregation
• ESP control processor:
– Allows for direct CPU access to the forwarding-engine subsystem (that is, Cisco QuantumFlow Processor) co-residing on the ESP
– Manages Cisco QuantumFlow Processor chipset
• SIP control processor:
– Provides direct CPU access to SPAs plugged into the given SIP for control purposes
– Runs SPA drivers for initializing and configuring SPAs
The control CPUs (as mentioned previously) in the Cisco ASR 1000 Series Router chassis (route processor, ESP control processor, and SIP control processor) run Cisco IOS XE Software, an operating system consisting of a Linux-based kernel and a common set of OS-level utility programs including Cisco IOS Software running as a user process on the route-processor card. Cisco IOS Software is based on the Cisco IOS Software Release 12.2SR train.
The Cisco IOS Software has no direct access to the hardware components in the system and is largely isolated from the platform architecture. This concept allows for different types of redundancy and modularity in the system. Even if the Cisco IOS Software is down (or has crashed), router administration personnel can still access the console and auxiliary console, and they can even perform Telnet, Secure Shell (SSH) Protocol, and Secure Sockets Layer (SSL) in the system and restart the Cisco IOS Software or perform Trivial File Transfer Protocol (TFTP) out the core dumps and other relevant information through the route-processor management port.
The Cisco IOS Software is responsible for the control-plane processing, including processing network configuration and the CLI, processing or directing Simple Network Management Protocol (SNMP) requests, running routing protocols, computing routes, managing interfaces and tunnels, and session setup.
Two Cisco IOS Software daemons on the 2RU and 4RU Cisco ASR 1000 Series Router configurations provide Cisco IOS Software redundancy and therefore limited interruption on Cisco IOS Software failure or upgrade. The normal Cisco IOS Software Nonstop Forwarding with Stateful Switchover (NSF/SSO) support is used to shadow state from the active Cisco IOS Software daemon to standby Cisco IOS Software instance whether on the same route processor or a different route processor (in the case of Cisco ASR 1006 chassis). It also reestablishes state upon Cisco IOS Software restart, resulting in a software high-availability option for all Cisco ASR 1000 Series Router chassis.
Because the 6RU chassis can accommodate two route processors, each route processor runs its own copy of Cisco IOS Software.
All failover times in the system (route processor to route processor, ESP to ESP, and Cisco IOS Software to Cisco IOS Software) are less than 50 ms, thus beating even the Automatic Protection Switching (APS) gold standard for nonstop operation.
Cisco offers a new major software release every 4 months with new features, and two rebuilds per major release, with the first rebuild 2 months after first customer shipment (FCS) of the major release and the second rebuild 4 months after FCS for bug fixes. Each functional element of the Cisco ASR 1000 Series Routers supports a different modular software package or binary for high availability; the following delineates these packages:
• Route processor
– RPBase: Route-processor OS
– RPControl: Control-plane processes that interface between Cisco IOS Software and the rest of the platform
– RPIOS
– RPAccess: Software required for router access; two versions are available: one contains open SSH and SSL and the other does not (that is, K9 and non-K9)
– ESPBase: ESP OS + Control processes + Cisco QuantumFlow Processor code
• ROM Monitor: One ROM Monitor package containing ROMmon for route processor, ESP, and SIP (released when needed)
Summary
The Cisco ASR 1000 Series Aggregation Services Routers constitute a true carrier-class system consisting of forwarding-plane redundant components, high availability, ISSU for Cisco IOS Software with NSF/SSO, and SPA drivers. These routers take advantage of the flexibility and faster services delivery based on the Cisco QuantumFlow Processor starting at 5 and 20 Gbps.
The Cisco ASR 1000 Series Routers offer many technological innovations while providing innovative carrier-class capabilities. These new midrange routers have advanced forwarding engines and multiple processors, and they take advantage of the proven features of Cisco IOS Software. Both enterprises and service providers can benefit from the modular design and advanced architecture of these routers.
