Today I decided to run though some labs, since the weather was crappy. The two router labs went well, but the three router labs started to give me some trouble.
I started getting the following message:
*Mar 1 00:16:35.203: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to down
Which a few seconds later would be followed by this message:
*Mar 1 00:16:35.203: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to up
I went through everything I could think of, and even cleared each routers config file multiple times. Baffled, and a bit frustrated, I walked away for a bit. When I came back, it dawned on me that I never checked the cables I was using (I had swamped them, but I did not check them).
Sure enough, a few pins pins on the serial cables that connected to my third 2513 router were bent. I examined the serial ports on that router and discovered that there were pins jammed in the connector. I can honestly say this was not caused by me, since I only have one set of Serial cables, and all of the pins on those were intact (but bent at this point).
So my problems are solved, for now. I will attempt to remove the pins form the router, but if that fails it may get replaced with another 2500 or more likely a 2600XM router.
Cisco Lab
My 2511 terminal server arrived today. Configuring it for each of my devices was surprisingly easy. All you have to do is issue an ip host command for each device you have connected. For example:
ip host 2513-01 2001 172.21.1.1
The “2513-01″ is the host name of the router. The “2001″ tells the terminal server what RJ-45 connector is attached to the devices console port. In this case, the device is attached to connector one. If it was attached to connector 11 the port number would be 2011, and so on. Each device will have the same IP address associated with it. This IP address is associated with a looback interface using the following commands:
interface Loopback1
ip address 172.21.1.1 255.0.0.0
That is a simple rundown of what you need to get a terminal server setup. Below is a link to a the Cisco page that I used to learn how to setup the server. That page will go into more detail as to the parameters that are used.
Configuring a Terminal/Comm Server
Cisco Lab
Studying for any sort of Cisco certification can get expensive very quickly, particularly when you factor in the cost of piecing together your own lab. One problem I have personally run into, is how to squeeze some lab work in while I’m away from home (at work or otherwise traveling). Having my entire lab powered up for eight hours or more, just so I could possibly run a lab exercise for 45 minutes at work did not seem efficient to me.
Recently, I have been playing with Dynamips, which is an emulator that allows you to run real Cisco IOS images. Experience with Linux made me feel right at home with the configuration and operation of the virtual Cisco devices in Dynamips. However, getting the hang of the configuration and inter-workings, could be confusing for some (including myself at points).
While browsing the Dynagen web site this morning, I came across a program called GNS3. This is a GUI interface that simplifies the use of Dynamips. Since it is a GUI, it allows you to see the topology of the network you are creating, which I find helpful.
The emulator in general is very handy when experimenting with certain things without purchasing additional hardware. I know many CCIE’s find Dynamips useful, since they have access to all of the downloads from Cisco. In addition, Dynamips can be bonded to a physical interface, allowing you to connect it to a physical lab or an outside network.
Below are links to the software I have talked about. Keep in mind, all of this software is free.
- Dynagen - Text-based front end for Dynamips router emulator
- GNS3 - GUI front end of Dynamips
CCNA Study, Cisco Lab
In the early stages of building my lab, I saw no need for a terminal server. In the recent days, switching console cables between two or more devices has become more of a hassle. Even with two USB to DB9 adapters and many more console cables, the time spent swapping cables adds up and sometimes distracts me from the actual lab.
A terminal server is a device that uses a breakout cable of sorts to connect to the console ports of many other devices. What you then do is use one console cable to connect to the terminal server, and initiate Telnet sessions to the other connected devices. In the world of Cisco labs, this terminal server is often a 2511 or 2509 router. These router models have asynchronous interfaces (the 2511 has two), each of which can usually support a terminal connection to eight devices with the proper cable.
Here is a quick list of the hardware that would be required:
- Terminal Server: Cisco Router (2511 or 2509)
- Octal cables
- Console cable and USB to DB9 adapter to console into the router
There are a few things to note. The 2511 and 2509 routers are not your only options. You can use a 2800 series router with the proper network module, however this will cost you considerably more. In addition, the 2511 has two asynchronous ports allowing you to connect up to 16 devices (using two octal cables). If you have more then eight devices, or you plan to expand you lab, the 2511 might be the router for you.
Prices for this stuff will vary. If you’re shopping on E-bay it seems your best bet is to try and scout out a package deal that comes with the router as well as the octal cable(s). Around $200 seems to be the running price for everything. If you are patient, you can find a better deal.
Once I get my terminal server and configure it, I will create a how-to document on configuring one for a lab setting. For now, this following Cisco article will provide the basics.
Configuring a Terminal/Comm Server
Cisco Lab
I went on a bit of a rampage over the last week purchasing some equipment to expand my lab. The stuff I purchased includes:
- 3640 Router (mentioned earlier)
- WS-C3550-24PWR-SMI switch (With three GBIC modules)
- WS-C3524-XL-A switch
The 3640 router arrived today, and it’s in great condition for the price I paid. The three foot power cables I ordered from Mono Price also arrived today. They cleaned up the cabling in my rack nicely, since I don’t have six feet of extra power cables coiled on the side of the rack.
Once the switches arrive and I confirm they are working, the next step will be to purchase some fiber to connect the switches. My goal is also to take pictures of everything after I get the two switches mounted and cabled.
Cisco Lab
I discovered that I cannot create 802.1Q trunks between my 2513 routers and my switch. This was all all I needed to push me to purchase the 3640 router I have been looking at for a while.
The router is going to come with a NM-2E2W network module (two Ethernet ports) and the DRAM and FLASH maxed out (64MB/16MB). This should be good to get me started. later on down the road I will probably add a serial module to connect this route to my 2513’s.
Next up will probably be a 3550 switch. I am trying to get one with the enhanced image to play around with some of the Layer-3 features.
Cisco Lab
Here is a quick list of the equipment that I currently have in my lab:
- 3 - Cisco 2513 Routers
- 1 - Cisco 2924 Switch
- 3 - AUI to Ethernet Transceivers (For the AUI ports on the routers)
- 3 - DCE to DTE Cables (Used for serial connections between routers)
- 1 - Skeletek 16U Rack
- 1 - Aneutronics 20 Outlet Rack mount Power Strip
- 1 - USB to DB9 Dongle
Most of this stuff was sourced from E-Bay. If you are patient, you can find some good deals.
The linked USB to DB9 dongle is probably the best I have used. I went through a couple different brands of varying prices, and most of them ended up crapping out on me. The Amazon price is a bit more then the price I paid, but shopping around will pay off. I also find it useful to have a six to ten foot long USB extension as well. This gives you more freedom to move around if you need to.
Eventually I will expand this equipment for more advanced labs and certifications. Some planned upgrades include:
- 16MB DRAM and 16MB Flash on all 2513 routers (Maxed out)
- One or two 3500 series switches
- A few better routers (2600 and 3600)
- VMware whitebox (for servers)
I will take some pictures of my the lab and post them later.
Cisco Lab