Cisco 12000 Series Routers

Overview

Cisco 12000 Series Gigabit Switch Routers

Introduction

The Internet is rapidly becoming an electronic agent for commerce, entertainment, communication, and information retrieval. New network-enabled intranet applications and powerful desktop computers are driving an exponential increase in network traffic. Service providers and enterprises are rapidly deploying packet-switching infrastructures to handle this tremendous growth in data traffic.

The Cisco 12000 series gigabit switch router (GSR) is the premier routing product family from Cisco designed and developed for the core of service provider and enterprise IP backbones. The Cisco 12000 GSR family includes three models: the Cisco 12008, 12012 and 12016.

The Cisco 12008 has eight slots that can be used to support up to 84 DS3, 28 OC-3c/STM-1c, and 28 OC-12c/STM-4c or 7 OC-48c/STM-16c interfaces.

The Cisco 12012 has 12 slots that can be used to support up to 132 DS3, 44 OC-3c/STM-1c, 44 OC-12c/STM-4c, or 11 OC-48c/STM-16c interfaces.

The Cisco 12016 has 16 slots that can be used to support up to 180 DS3, 60 OC-3c/STM-1c, and 60 OC-12c/STM-4c or 15 OC-48c/STM16c interfaces, with support for 15 OC-192c/STM-64c interfaces in the future.

The Cisco 12000 series GSR products are architected to meet the bandwidth, performance, services, and reliability requirements of today's IP core backbones.

Scalable Bandwidth

Modular, multigigabit crossbar switching fabric allows bandwidth to scale in flexible increments: 40 Gbps for the Cisco 12008, 60 Gbps for the Cisco 12012, and 80 Gbps for the Cisco 12016.

Figure 1   Cisco 12000 Series

Scalable Performance

Scalable Services

Carrier-Class Design

Network Equipment Building System (NEBS) and European Telecommunications Standards Institute (ETSI) compliance enables installation in service provider central offices.

Cisco 12000 GSR Architecture

System Level

The Cisco 12000 GSR is based on a high-speed distributed routing architecture combined with a state-of-the-art switching core that delivers Layer 3 routing at gigabit speeds.

The Cisco 12000 GSR is optimized for performing routing and packet-forwarding functions to transport IP datagrams across a network. The routing function is performed in the gigabit route processor (GRP) responsible for running the routing protocols and building the routing tables from the network topology. This information is then used to build the forwarding tables distributed to the LCs. In addition, the GRP is also responsible for the system control and administrative functions.

The packet-forwarding functions are performed by each of the LCs. A copy of the forwarding tables computed by the GRP is distributed to each of the LCs in the system. Each LC performs an independent lookup of a destination address for each datagram received on a local copy of the forwarding table, and the datagram is switched across a crossbar switch fabric to the destination LC.

All cards are installed from the front of the chassis and plugged into a passive backplane. This backplane contains serial lines that interconnect all the LCs to the switch-fabric cards as well as other connections for power and maintenance functions. Each slot in the GSR has up to four serial line connections (1.25 Gbps), one to each of the switch-fabric cards (see below) to provide a total capacity of 5 Gbps per slot (2.5 Gbps full-duplex).

The major components of the GSR are the switch fabric, GRP, and LCs.

Switch Fabric

At the heart of the Cisco 12000 GSR is a multigigabit crossbar switch fabric that is optimized to provide high-capacity switching at gigabit rates. The crossbar switch enables high performance for two reasons: connections from the LCs to a centralized fabric are point-to-point links that can operate at very high speeds and multiple bus transactions can be supported simultaneously, increasing the aggregate bandwidth of the system. A GSR system can be configured as 40 Gbps for the Cisco 12008, 60 Gbps for the Cisco 120012, and 80 Gbps for the Cisco 12016.

The switch fabric includes two card types: switch-fabric cards (SFCs) and clock and scheduler cards (CSC). Each GSR must have at least one CSC in the chassis. The CSC handles requests from LCs, issues grants to access the fabric, and provides a reference clock to all the cards in the system to synchronize data transfer across the crossbar. The SFCs receive the scheduling information and clocking reference from the CSC cards and perform the switching functions.

It provides the following key functions:

Gigabit Route Processor

The GRP is a high-performance engine that provides the routing intelligence for the Cisco 12000 GSR family. It is dedicated to determining the network topology and calculating the best path across the network. The GRP has the following hardware characteristics:

The GRP provides the following key functions:

Line Card

LCs connect the GSR to other devices via electrical or optical media. The LCs are designed for the transmission of IP packets over DPT, PPP, Frame Relay, or ATM interfaces. The features and functions of the LCs are interface specific.

Dynamic Packet Transport

DPT interfaces on the GSR enable connections to other Cisco 12000 GSRs or other Cisco routers such as the Cisco 7500, via dual counter-rotating optical rings. DPT rings can be provisioned over dark fiber, wave-division multiplexing (WDM), or SONET/SDH infrastructure. The GSR currently offers the following DPT interfaces:

Table 1 shows key features of the DPT interfaces.

Table 1   Key Features of the DPT Interfaces

Key features of the DPT LC include the following:

Packet over SONET/SDH

Packet over SONET (PoS) interfaces on the GSR enable connections to other Cisco 12000 GSR or other Cisco routers such as the Cisco 7500 or 7200, via optical interfaces. These interfaces can be circuit provisioned over a SONET/SDH infrastructure or dark fibers, connections, or wavelength WDM systems. The Cisco 12000 GSR offers the following PoS interfaces:

Table 2 outlines some of the key features of the PoS interfaces.

Table 2   Key Features of the PoS Interfaces

Asynchronous Transfer Mode

ATM interfaces on the Cisco 12000 GSR enable connections to other Cisco 12000 GSRs or other Cisco routers such as Cisco 7500 or 7200, via ATM networks. The GSR offers the following ATM interfaces:

Table 3 shows some of the key features of the ATM interfaces.

Table 3   Key Features of the ATM Interfaces

Ethernet

Gigabit Ethernet (GE) and Fast Ethernet (FE) interfaces on the GSR enable connections to other Cisco 12000 GSR or other Cisco routers such as Cisco 7500 or 7200. The Cisco 12000 GSR offers the following Ethernet interfaces:

Table 4 shows some of the key features of the Ethernet interfaces.

Table 4   Key Features of the Ethernet Interfaces

Table 5   Technical Specification

* Output power will vary depending upon configuration. Value will generally be lower for typical configurations.

Regulatory Specifications

Cisco 12000

Safety

EMI

Immunity

NEBS

ETSI