Table of Contents

Router Features
WAN Interface Cards
Rear-Panel Connectors
Router Memory

Run-From-Flash Architecture
Run-From-RAM Architecture
Identifying the Memory Architecture from Cisco IOS

Unpacking the Router
Equipment That You Must Provide

Overview of the Router

Cisco  1600 series routers are a family of small desktop routers that link small-to-medium remote Ethernet LANs to regional and central offices over multiple WAN connections.

This chapter contains the following sections:

• Router Features

• WAN Interface Cards

• Rear-Panel Connectors

• Router Memory

• Unpacking the Router

• Equipment That You Must Provide

Router Features

Listed below are some features of the Cisco  1600 series routers:

• One or two Ethernet LAN connections, using either the 10BaseT or AUI LAN ports. (Refer to Table 1-1 for more information about the LAN connections supported by each model.)

• One fixed WAN port (except for the Cisco  1605). (Refer to Table 1-1 for more information about the WAN connections supported by each model.)

• One slot for a WAN interface card, for flexibility in choosing WAN connections that the router supports. (Refer to the section "WAN Interface Cards" later in this chapter for more information about WAN interface cards.)

• Flash memory PC card (PCMCIA-compatible), which can be preconfigured by a network administrator and installed in the router at a remote site.

• Console port, which supports router management using a terminal or a PC with terminal emulation software.

• Router management over the network using Simple Network Management Protocol (SNMP).

• AutoInstall for downloading configuration files automatically over a WAN connection.

• Security slot for Kensington-compatible lockdown cable.

Table 1-1 describes in detail the types of LAN and WAN connections that are supported by each of the five router models.

WAN Interface Cards

On the Cisco  1601 through Cisco  1604, you can use the WAN interface card connection as a secondary WAN connection, which can be used if the router on-board WAN connection fails. On the Cisco  1605, you can choose the type of WAN connection that you want for your network.

Rear-Panel Connectors

Figure 1-2 through Figure 1-6 illustrate the connectors for each of the five router models.

Table 1-2 describes the connectors on the rear panel of the router.

Router Memory

The Cisco 1600 series routers are either of run-from-flash (RFF) or run-from-RAM (RFR) models. Router model names with an R are RFR routers; all other models are RFF. In this document, model names without an R refer to both RFF and RFR models, except where noted. This section describes the two memory architectures used in the Cisco  1600 series routers.

Run-From-Flash Architecture

With RFF, the microprocessor uses the uncompressed Cisco IOS software image that is stored in Flash memory. The software image runs directly from Flash memory. RAM stores working data such as Cisco  IOS data structures, network routing tables, and packets to be transmitted to and received from network interfaces.

The running software image cannot be used to download new software to Flash memory because it would attempt to overwrite itself. (However, when you are using Dual Flash Bank memory, you can download the new software image into a different Flash memory partition.)

To download a new software image without using Dual Flash Bank memory, a boot-helper image (called XBOOT) has been added to the ROM on the RFF models. The boot-helper image is a small subset of Cisco  IOS software that supports only a subset of the interfaces and the WAN protocols. RFF ROM supports the following WAN interfaces. (These are all onboard interfaces, not WAN-interface-card interfaces.)

• Serial (synchronous and asynchronous) (Cisco 1601)

• DSU/CSU (Cisco 1602)

• ISDN S/T (Cisco  1603)

• ISDN U (Cisco 1604 and Cisco 1604 R)

When upgrading the Cisco IOS software in Flash memory, you must boot the router from the ROM image. The Flash memory can be overwritten because the Cisco  IOS software that is stored in Flash memory is not being used to run the router.

Run-From-RAM Architecture

With RFR, the Cisco IOS image is stored in Flash memory (usually in compressed form), but is loaded into RAM before being used to operate the router. The running software image then resides in RAM, so a new software image can be downloaded and copied over the software image stored in Flash memory.

In RFR routers, only a minimal boot-helper image is stored in the ROM for disaster recovery. Initial loading of a software image into Flash memory is done over the console port or the local Ethernet.

Because the Cisco IOS image is stored in compressed form in Flash memory and then decompressed when loaded into RAM, the standard configuration for the RFR models contains less Flash memory but more DRAM than the RFF models.

Table 1-3 is a summary comparison of these two memory architectures.

Table 1-3: Memory Architecture Comparison

Feature	Run-From-Flash Routers	Run-From-RAM Routers
Cisco IOS software online  download	Yes, when using Dual Flash Bank memory	Yes
Flash memory use	Stores uncompressed Cisco  IOS software image. The Flash PC card cannot be removed when the router is operating.	Stores compressed Cisco  IOS software image. The Flash PC card can be removed after the router has finished booting up and has passed the power-on self-test.
RAM use	Packet memory Routing tables Dynamic memory used by Cisco  IOS software	Packet memory Routing tables Dynamic memory used by Cisco  IOS software Running uncompressed Cisco  IOS software image
DRAM capacity	Standard: 2  MB onboard Maximum:  18 MB (with 16-MB SIMM)	Standard: 8  MB onboard Maximum: 24 MB (with 16-MB SIMM)
Flash PC card capacity	Standard: 4  MB Maximum:  12 MB	Standard: 2  MB Maximum: 12 MB
Disaster recovery (Router fails and the image store in Flash memory is corrupted).	Cisco IOS software image can be downloaded over any interface and with any WAN protocol supported by the ROM boot helper. Cisco IOS software image can be downloaded over the console port by using the xmodem or ymodem commands. Flash PC card can upgraded by booting from a Cisco IOS software image stored in another Flash memory bank (if using Dual Flash Bank memory).	Cisco  IOS software image can be downloaded with the ROM boot helper over the Ethernet 0 interface. Cisco IOS software image can be downloaded over the console port by using the xmodem or ymodem commands. Flash PC card can upgraded by booting from a Cisco IOS software image stored in another Flash memory bank (if using Dual Flash Bank memory).

Identifying the Memory Architecture from Cisco IOS

Use the Cisco  IOS show version command to display some memory architecture information for your router (show in boldface in the example output):

• Amount of onboard DRAM (a type of RAM)

• Whether the Cisco IOS software is running from RAM or Flash memory

• Amount of Flash memory

Router# show version

Cisco Internetwork Operating System Software 

IOS (tm) 1600 Software (C1600-BNSY-M), EARLY DEPLOYMENT RELEASE 
SOFTWARE 11.2(9)P

Copyright (c) 1986-1997 by cisco Systems, Inc.

Compiled Mon 11-Aug-97 14:10 by cisco

Image text-base: 0x02005000, data-base: 0x02477BD0

ROM: System Bootstrap, Version 11.1(12)AA,DEPLOYMENT RELEASE 
SOFTWARE (f)

ROM: 1600 Software (C1600-RBOOT-R), Version 11.1(12)AA, EARLY 
DEPLOYMENT RELEASE

Router uptime is 12 minutes

System restarted by power-on

System image file is "flash:c1600-bnsy-mz", booted via flash

cisco 1605 (68360) processor (revision C) with 7680K/512K bytes of 
memory.

Processor board ID 06027889, with hardware revision 00000000

Bridging software.

X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.

2 Ethernet/IEEE 802.3 interface(s)

System/IO memory with parity disabled

8192K bytes of DRAM onboard

System running from RAM

8K bytes of non-volatile configuration memory.

4096K bytes of processor board PCMCIA flash (Read/Write)

Configuration register is 0x2102

Unpacking the Router

Figure 1-7 shows the other items that come with your router. All of these are in the accessory kit that is inside the box that your router came in.

Equipment That You Must Provide

Figure 1-8 shows items that you will have to provide to install your router. You will require only some of these items, depending on what Cisco  1600 model you are installing.

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