Cisco Networking Answers » Do You Know?

Before buying an RPS for Cisco Catalyst Switches

MustafaAksu — Wed, 07 Jan 2009 12:18:22 +0000

There are two issues that you have to be aware of when you are evaluating RPS solutions for fixed Cisco catalyst switches. Cisco has a product named Cisco Redundant Power System 2300 (RPS 2300) for the non-modular switch series like Catalyst 3560, Catalyst 3750. This is the successor of old Cisco Redundant Power System 675 (RPS 675).

You have only one bullet in your gun when you have an RPS

Switch draw power from RPS after power fail

You can provide a limited redundancy to your network by installing an RPS for your Catalyst Switches. Switch survives without rebooting when main power goes off. It draws power from RPS, but it never return back to main power. An orange LED shows the switch powered by RPS. If you press the standby/active button on the RPS, your switch will reboot and become a normal operation. The only exception is E series switches + RPS 2300 combination. This combination could restore power state without rebooting.

RPS supports only one switch(in some cases two) at one time

Some of the switches will fail with a power circuit fail

You can attach up to 6 switches to an RPS, but if power Circuit 1 fails as shown in the above scenario then RPS only can support one switch and the rest will fail. RPS 2300 can support 2 switches if power requirements are moderate, but no more.

Standalone or stackable Cisco switches do not support NetFlow

MustafaAksu — Sat, 11 Aug 2007 09:00:19 +0000

NetFlow is a must have technology suitable for mid size to enterprise companies. Nowadays, it has become an IEEE standard as IPFIX (Internet Protocol Flow Information eXport). We will be able to find NetFlow technology support on any brand in the market soon. However, which devices of Cisco itself supports NetFlow technology?

All routers including the oldest (e.g. Cisco 2500 series) and smallest (e.g. Cisco 800 series) support NetFlow. Some functions does not exist in older IOS versions.
Catalyst 6500 series switches support NetFlow. Catalyst 4500 series switches support NetFlow with Supervisor IV/V + WS-F4531 Catalyst 4500 NetFlow Services Card.

Standalone or stackable switches do not support NetFlow. This means Catalyst 4948, Catalyst 3750 or Catalyst 3560 series switches do not support NetFlow. You can see the necessary commands on config mode, but they are not effective. It is not about IOS version or feature set. You need a modular switch for NetFlow.

Unfortunately, the answer of “What Cisco switches support netflow?” is only the modular switches.

HSRP Group IDs are limited to 16 on PFC2

MustafaAksu — Sun, 29 Jul 2007 15:17:40 +0000

On the catalyst 6500 switches, the maximum number of HSRP group IDs are limited to 16 in the Supervisor Engine 2-based systems. This limit is 256 in all other older and newer systems.If you try to create a new standby group after this limit you recieve

More than 16 standby groups not supported in this platform.

message.Cisco says that this is a per interface limit. So, you can use same ID in several interfaces.

You can find the details on “HSRP Group Limitation on Catalyst 6500/6000 Series Switches Frequently Asked Questions”

Cisco Learning Credits

MustafaAksu — Sat, 28 Jul 2007 18:59:49 +0000

Getting training from Cisco is possible like buying a router. The process is similar to SMARTnet. You can simply add TRN-CLC-000 ( 10 Prepaid Training Credits:Redeem W/Cisco Learning Partners ) to your kit list and you have 10 Credits for training.

How can I use these credits?
You can use these credits for any training you need. You just have to check the required amount of credits from cisco.com to get trained. For example, you need 29 CLCs (Cisco Learning Credits) for Building Cisco Multilayer Switched Networks training (BCMSN). You can also attend the Networkers online. For the full conference pass, you need 19 CLCs.

Why should I buy CLCs instead of training?
If you work in a small company, you do not need it. But if you are working in a big organization (government, enterprise companies) it can be a real headache for you to participate in training. You should have within the training budget and it must be approved by HR department. This is not a simple process and involves permission from many people.

Otherwise, you have to prepare a kit list which includes hardware, software, SMARTnet and CLCs. All of them will be purchased together. In this way, if the logistics department comes with a wireless project in the middle of the fiscal year or the bosses decided to buy some security products after a security audit, then they will pay for necessary training without much discussions.

For the details please check “Cisco Learning Credits”.

Cisco Aironet Power Injector Media Converter

MustafaAksu — Sat, 28 Jul 2007 15:20:14 +0000

If you need a wireless solution on industrial areas like factories or warehouses, Cisco Aironet 1240AG Series Access Point would be a good option for you. The hardened case, wide range of antenna options and capabilities just make you feel that it is the best device. Unfortunately, if you have a closer look, you will see that this device only has a UTP (Copper) Ethernet port but no fiber options (Other models do not have fiber ports either). You require fiber to reach access points that are located at the far ends of a large warehouse. Moreover, you can have concerns about using a media converter from other vendors.

In this case Cisco has a solution.Cisco Aironet Power Injector Media Converter (AIR-PWRINJ-FIB) is a media converter and a Power over Ethernet (PoE) source. You just need a UTP cable between device and Access Point. You can place the device on a more convenient place than the access point. Thus, you do not need power cabling on the roof of the warehouse.

For the details please check the Cisco web site:Cisco Aironet Power Injector Media Converter