Cisco AGS+ upgrade (version 2)

 Cisco AGS+ upgrade 

From the year 1995

Advanced Gateway Server (AGS)

The AGS+ is the successor to Cisco’s AGS router, which was released in 1986 and is widely recognized as the first commercial multi-protocol router that could link multiple LAN and WAN networks. 

The software was originally developed by Bill Yeager at Stanford, then licensed and enhanced by Cisco founders Len Bosack and Sandy Lerner.

This was the 5,000th AGS!! 

 My thanks to Merrill Mcadams for the photo

Why 1995?

Because the AGS+ that I have on the lab, the EPROM memory chips have IOS 10.2(2) and are date stamped 1995. Therefore my pretend IOS upgrade is set back then.

The year is 1995, Toy Story and Apollo 13 movies are screening, while Kiss from a Rose/Seal and All I Wanna Do/Sheryl Crow were in the pop charts. Not forgetting Windows 95 kicked out Windows 3.1

Just to refresh your memory

In order to appreciate the pain from back then, here's a quick review of memory systems follows

Erasable Programmable Read-Only Memory

The Cisco AGS+ routers use EPROM chips meaning that they have to be physically replaced with new EPROMs containing the upgraded code. EPROM (Erasable Programmable Read-Only Memory) were programmed (burned) electrically.  The memory was erasable using strong ultraviolet light exposed thru a quartz window on the top of the chip package. EPROMs had to be completely erased before being able to be reprogrammed one byte at a time. 

"through the round window, we can see...."

EPROM complete with quartz window

Due to the high manufacturing cost of the quartz window, OTP (One Time Programmable) chips were released. Here, the die is installed in an opaque package, so it can’t be erased after programming - this also eliminates the need to test the erase function, thereby further reducing costs.

Then came the...

Electrically Erasable Programmable Read-Only Memory

Today, we are lucky, we use EEPROM (Electrically Erasable Programmable Read Only Memory), also known as E2PROM, were chips that improved upon previous EPROM technology, they were programmed electrically but could also be erased electrically without the need for UV light. 

Using the EEPROM and IP file transfer protocols (TFTP/FTP) router OS upgrades are by far the way much faster and convenient today.

The (pretend) AGS+ router upgrade

Back in 1995 the AGS+ only used EPROM memory technology, so to upgrade you had to physically remove and replace eight memory chips.

Your project is to upgrade five cisco AGS+ routers for your UK customer. The routers are located at the following customer sites:

London Telehouse East          x2       AGS+ routers   

London Telehouse West         x1       AGS+ router

Bristol                                     x1       AGS+ router

Manchester                            x1       AGS+ router

You're going to need 40 EPROM chips

Each router uses eight EPROM chips to store the IOS image. Because there are five routers to upgrade and each router needs eight EPROM chips, a total of forty EPROM chips are required.

Each of these chips has to be carefully labelled ‘U41 to U49’. Care must be taken replacing them, grounded ESD wrist-straps to be used. Chip puller tool (more typically a small flat-blade screwdriver) to extract the chips. Then insert the new chips the right way round (small cut-out on the top of the chip). 

 

The procedure needs a maintenance window because you have to power off the router, remove the front panel, pull off the ribbon cables and remove the processor/CPU board from slot 2. Only then can the eight chips can be replaced.

Switch Off

Remove Front Panel and the cables to slot-2, the Processor card

The Processor card, EPROM chips on the right

These EPROMs have IOS 10.2(2)

Then replace the CPU board, ribbon cables and front panel. Power back on and check it is working properly. 

That’s one router – now drive to the other locations

 

Now you need to drive to the other London location then on to Bristol and Manchester. It will take several days or weeks, subject to obtaining maintenance windows from the customer. Such fun!

Contrast this with today.. 

 

Contrast this with today, working from home and put the kettle on and make a brew! 

Spin up your VPN and...

 

Obtain maintenance window from the customer.

1.     Copy the new IOS image to a drive using tftp/ftp/ssh

3.    Login to the first router using SSH.

4.     Enter copy tftp: flash: 

5.     Provide the ip address and file name for the router to go and fetch the IOS image

6.     After download – now the IOS image safely stored in the router’s EEPROM, edit the boot system variable to point to the new IOS image and reload the router.

7.     To upgrade the remaining four routers, repeat or, providing the next router to be upgraded is reachable from IP, then you can enable a local tftp server on the newly upgraded router and from the next router just copy tftp.

Obviously with network management, the above may be done with the click of the mouse

 Finally, For Your Interest...

Documentation

For AGS+ Documentation click  -->  here (DropBox link)

 The Configuration Register 

The configuration register lives on the edge of the processor card from slot two. Back then there were no keyboard commands to adjust this.  You have to open the router, find the processor card slot 2 and insert or remove physical links then reload for it to work.

The Config Register

FYI travel back in time to the Internet '96

Cisco Connection Online (CCO) in 1996 click --> here

This is the earliest capture on its site for cisco in the Wayback Machine archive.