HSRP 2

The default gateway plays a huge role in IP networks. How do redundant default gateways back each other up? How do you control which is the active gateway when all is well, and what happens during the recovery process? This latest lab focuses on those small configuration options for #HSRP, with some more configuration practice for #CCNA.

Requirements

Configure HSRP on R1 and R2 for a typical case of HSRP, providing a redundant default gateway for PC1 in the figure. The lab begins with all router interfaces shown in Figure 1 working, and with IPv4 addresses configured. You can use the design in Figure 1 or Figure 2; on the LAN, just make sure both routers and both hosts are in the same VLAN and can ping each other. Your job is to add the HSRP configuration per the following rules:

• Use the highest available IP address in the shared subnet for the HSRP virtual IP address
• Use the HSRP group number 20
• Use HSRP Version 2
• Ensure that R1 acts as the HSRP active route under normal conditions by increasing R1’s priority by 10 and decreasing R2’s priority by 10 versus the default setting.
• Ensure that if R1 fails, and later recovers, that R1 was not cause a failure.
• Name the HSRP group: “HSRPLab”.

Figure 1: HSRP Design, One LAN Switch

Figure 2: HSRP Design, Two LAN Switches

Initial Configuration

Example 1 and 2 show the beginning configuration state of R1 and R2.

Example 1: R1 Config

Example 2: R2 Config

Additionally, note that the switches need to create a working VLAN so that both routers’ G0/1 interfaces and both PCs can communicate over that VLAN. If you built the lab like Figure 1, with a single switch, the switch could have all default configuration, with all devices in VLAN 1. With two switches, if you use VLAN 1, you should be fine with default configuration regardless. Examples 3 and 4 provide some initial configuration in case need to use another VLAN (VLAN 2) instead of VLAN 1, and you need to ensure that VLAN trunking is used.

Example 3: SW1 Config

Example 4: SW2 Config

Answer on Paper, or Maybe Test in Lab

Next, write your answer on paper. Or if you have some real gear or other tools, configure the lab using them.

Verifying HSRP can be done with a command and a little testing. To verify, use the show standby brief command on both routers. One router should be in a state of “Active”, the other as “Standby”. Both should list the same virtual IP address.

For testing, if you have a host, change its default gateway to the HSRP IP address. Then start a long-running ping command on your host for one of the IP addresses on the link between the two routers that sits in another subnet (10.10.10.1 or 10.10.10.2). This ping should work no matter which router acts as HSRP active. Start the ping, go to the router that is currently active, and shutdown the G0/1 interface. HSRP should failover to the other router, your ping command should have a brief interruption, and then the ping should start working again.

To create a long-running ping on Windows, add a –t to the end of the ping command. On OSX and Linux, the ping command needs no extra parameters – it should run until you stop it (Ctrl-c).

Do this Lab with Cisco’s CML (Formerly VIRL)

You can do these labs on paper and still get a lot out of the lab. As an extra help, we have added files for Cisco Modeling Lab – Personal (CML-P). CML-P replaces Cisco Virtual Internet Routing Lab (VIRL) software, in effect serving as VIRL Version 2.

Below, find two files: a file useful with CML-P and another useful with VIRL. (Note that the CML-P file has a .yaml filetype, while the older VIRL file has a VIRL filetype.) Once the file is loaded, CML-P or VIRL will create a lab topology similar to this lab’s topology, with the initial configuration shown in the lab as well.

This lab’s CML file!

This lab’s VIRL file!

Note that while many Cisco switches no longer support ISL as a trunking protocol, the layer 2 switch image in CML/VIRL does, so it needs to be configured to know whether to use ISL or 802.1Q. The lab exercise does not mention this fact. So, FYI, the .VIRL file includes this command (already configured) so trunking will work:

Network Device Info

This table lists the interfaces changed in this lab to work well in CML/VIRL.

Host Device Info

This table lists host information pre-configured in CML/VIRL, information that might not be required by the lab but may be useful to you.

Handy Host Commands:

To see PC IP address: ifconfig eth1

Ping example: ping -c 4 10.1.1.1

Trace example: tracepath 10.1.1.1

To connect to another node within the topology: telnet 10.1.1.1