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Tech Guide: ASR 1000s Simplified

Category: Tech Guides

Doing more with less is the primary goal of the ASR 1000 Series Routers, made especially for businesses looking to scale and consolidate data centers and devices. With the firewall, deep-packet inspection, and session border control capabilities built into the ASR box itself, this router offers a wealth of capabilities without requiring additional hardware.

It’s not uncommon to get overwhelmed with all the options that the ASR has to offer. Ultimately, it’s important to understand what’s right for your network. That’s why we teamed up with expert engineers to detail the ASR’s three components, chassis capacity, and fixed hardware and help you decide for yourself.

The ASR 1000 is Cisco’s mid-range router line, capable of anywhere from 2.5Gbps to 100Gbps of throughput, depending on model and installed cards. The platform is targeted towards applications such as BGP border router, broadband aggregation, IPSec aggregation, large-scale NAT gateway, or high-capacity session border controller. The ASR 1000 provides a hardware forwarding engine to ensure consistent throughput regardless of the system’s configuration.


The ASR 1000 line consists of a variety of chassis — some with fixed components like the ASR 1001, ASR 1002, and ASR 1002-X — while other systems are fully modular, like the ASR 1004, 1006, and 1013. The chassis capacity and fixed hardware is detailed in simplicity here:

ASR 1001

1 SPA card slot

4x SFP slots onboard

Integrated RP2

Fixed ESP (2.5Gbps base, license upgradeable to 5Gbps)

ASR 1002

3 SPA card slots

4x SFP slots onboard

Integrated RP1

Integrated SIP10

Option of ESP5 or ESP10

ASR 1002-X

3 SPA card slots

6x SFP slots onboard

Integrated RP2

Integrated SIP40

Fixed ESP (5Gbps base, license upgradeable to 10, 20 or 36Gbps)

ASR 1004

1x RP slot

1x ESP slot

2x SIP card slots

Option of RP1 or RP2

Option of ESP10, ESP20, or ESP40

ASR 1006

2x RP slots

2x ESP slots

3x SIP card slots

Option of RP1 or RP2

Option of ESP10, ESP20, ESP40, or ESP100

ASR 1013

2x RP slots

2x ESP slots

6x SIP card slots

Can take an RP2

Option of ESP40 or ESP100

RP (Route Processor)

The ASR 1000 route processor is the component of the router that runs the IOS, manages the system, and performs all control plane functions (such as setting up VPN tunnels, initiating SIP sessions, and running the routing protocols).

Currently, two RP models are available, with the RP1 supporting up to 4GB of memory and the RP2 supporting up to 16GB of memory. For high availability and in-service software updating, the ASR 1000 RP is capable (with appropriate licensing) of running two IOS images in an active/standby arrangement, and due to this, only half the installed memory is available to the running IOS image.

ESP (Embedded Services Processor)

The ESP card is the forwarding engine of the ASR 1000—the RP constructs the forwarding table, which is then sent to the ESP, which performs all forwarding, encryption, and other packet manipulation. ASR 1000 ESPs are available in throughputs ranging from 2.5Gbps to 100Gbps of throughput. Note that using the ESP40 or ESP100 requires the use of an RP2.

SPA Cards and Carriers

The ASR 1000 uses SPA cards exclusively for interfaces. While smaller chassis like the ASR 1001 and ASR 1002 present SPA card slots, larger systems like the ASR 1004 and up require the use of an ASR 1000 SIP carrier card to provide SPA card slots. There are two SIP card models available: the SIP10 (up to 10Gbps of throughput) and the SIP40 (40Gbps of throughput).

When using these SIP cards, be aware of these restrictions:

  • The SIP10 can be oversubscribed up to 2:1; any further oversubscription will result in SPA cards being shut down by the system.
  • As the SIP40 provides 40Gbps of throughput, and the fastest SPA card is a 1 port 10GbE card, there is no way to oversubscribe the SIP40 at this time.


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