Router Flash Memory

Hello Friends,

In this post, we learn details of Flash memory of Router and how flash memory serial number helps to recognize  the features of Router and Memory.

Lets starts with Flash Memory:

Flash Memory is EEPROM.

Flash Memory stores IOS.

If system image file is: "flash:C3620-ik9o3s7-mz.123-25.bin"

Table 1.

Image Letter        Feature Set

I                   IP

Y                   IP on 1700 series platform

S                   IP Plus

S6                  IP Plus - No ATM

S7                  IP Plus - No Voice

J                   Enterprise

O                   IOS Firewall/Intrusion Detection.

K                   Cryptography/IPSEC/SSH

K8                  56 bit DES Encryption/Weak Cryptography

K9                  3DES/AES Encryption/Strong Cryptography

X                   H323

G                   Services Selection Gateway

C                   Remote Access Server/Packet Data Serving Node

B                   Apple Talk

N                   Novel IP/IPX

V                   VOX

R                   IBM

U                   Unlawful Intercept

P                   Service Provider

Telco               Telecommunication Feature Set

Boot                Boot Image(Used on high end Routers/Switches)

Table 2

Image Letter       IOS boot location

F                  The image executes from flash memory

M                  The image executes from RAM

R                  The image executes from ROM

L                  The image is relocatable

Z                  The image is compressed using ZIP format

X                  The image is compressed using MZIP format

W                  The image is compressed using STAC format

When we break down the naming convention of the image name:-

C3620   = Hardware

ik9o3s7 = Feature Set (Table 1)

mz      = IOS boot location(Table 2)

123     = Maintainance Release

25      = Individual Release

.bin    = File Extension Name