How To Configure HSRP

Below are my notes for the CCNP Routing & Switching SWITCH 300-115 certification exam. I used two Cisco 3560 switches and GNS3 to perform my labs. For theory, I used Cisco Configuration Guides and the Cisco Press Official Certification Guide.

Hot Standby Router Protocol, HSRP, is a Cisco proprietary protocol to make multiple routers or switches appear as one gateway. The gateway is where the redundancy is provided. For each redundant gateway, there is a common HSRP group. One router/switch becomes the primary HSRP router and another is selected as the standby HSRP router. Any other devices part of the group are in the listen HSRP state.

HSRP Configuration

R1 and R2 will be HSRP enabled.

At a 3 second interval, routers send HSRP hello messages to become aware if the other is up or down (between Active and Standby). The hold time value is 10 seconds or three times the hello timer. These hello messages are sent to the multicast address 224.0.0.2 using UDP port 1985.

There can be up to 255 HSRP groups and they are only locally significant.

Election of an active and standby HSRP router is based on a priority value of 0 through 255. By default, the priority is 100 but the highest priority value becomes the active router for the HSRP group. If there is a tie, the router with the highest IP address becomes the active router.

When HSRP is enabled, an interface goes through the following states:

  • Disabled
  • Init
  • Listen
  • Speak
  • Standby
  • Active

Configuration

I will use R1 and R2 as the two routers to provide a redundant gateway for 192.168.1.1.Continue Reading…

An Overview of inSSIDer

inSSIDer Wireless

If you are in need of planning or troubleshooting wifi but you’re on a budget, then inSSIDer by Metageek may be a good start for you. inSSIDer is a tool used to show you what your wireless environment looks like.

inSSIDer comes in two version, inSSIDer and inSSIDer Office.

inSSIDer

  • $19.99
  • Uses built-in wifi
  • For Windows and Mac

inSSIDer for Office

  • $199.99
  • Includes Wi-Spy Mini
  • Assists in troubleshooting interference

Radios and ESSIDs

When you open inSSIDer, and depending on whether you organized the main pane via Radio or ESSID, you will be presented with a list. When organized by Radio you get a number of columns:

All the columns presented by inSSIDer

  • Radio’s MAC address
  • Broadcasted SSID
  • What channel the SSID is on
  • Signal strength (in dBm)
  • Protocol
  • Security
  • Data rates

Select Radio or ESID

Selecting Radio is great if there is usually one access point. If you see two channels listed under the Channel column, e.x. 36+40, it means that wireless network is channel bonding to utilize two 20 MHz channels to form a single 40 MHz channel for increased bandwidth.

Select ESSID and the list of wireless networks will be organized by the SSID name. This is useful if there are multiple access points broadcasting the same SSID. You get the same columns but in addition there is a BSSID count which will tell you how many radios are seen for a particular SSID.

On the first column, under Radio or ESSID, you may see a chain link icon. That shows what SSID your laptop is associated with.Continue Reading…

What Are Your Challenges?

In IT, we are always surrounded by challenging tasks. Whether it is troubleshooting a routing issue, fixing an outage or planning a new wireless deployment we run into many challenges.

Here is my question to you:

What is your biggest challenge right now?

Let me know in the comments below.

My current challenge is balancing work with an MPLS and QoS design with CCNP ROUTE studies and family. Somewhere in between all of that I try to sleep ;)

What is the big item on your plate?