HSRP 1

#HSRP solves one of many design issues by avoiding a single point of failure in a network by having two or more routers share the role of default gateway in a subnet. This lab takes a look at a basic HSRP config, for the usual reason: to get some reps in for practicing basic CCNA configs.

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 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. For this lab, you will focus on the router configurations, not the switch configurations.

Your job is to add the HSRP configuration per the following rules:

• Use the lowest available IP address in the shared subnet for the HSRP virtual IP address
• Use the HSRP group number 10
• Make R2 act as HSRP primary under normal conditions
• Use only the required commands

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

interface GigabitEthernet0/1
 no shutdown
 ip address 192.168.100.254 255.255.255.0
!
interface GigabitEthernet0/2
 no shutdown 
 ip address 10.10.10.1 255.255.255.252

Example 2: R2 Config

interface GigabitEthernet0/1
 no shutdown
 ip address 192.168.100.253 255.255.255.0
!
interface GigabitEthernet0/2
 no shutdown 
 ip address 10.10.10.2 255.255.255.252

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 you 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

hostname SW1
!
interface FastEthernet 0/1
 no shutdown
 switchport access vlan 2
!	
interface FastEthernet 0/2
 no shutdown
 switchport access vlan 2
!
interface GigabitEthernet 0/1
 no shutdown	
 switchport mode trunk

Example 4: SW2 Config

hostname SW2
!
interface FastEthernet 0/1
 no shutdown
 switchport access vlan 2
!
interface FastEthernet 0/2
 no shutdown
 switchport access vlan 2
!
interface GigabitEthernet 0/1
 no shutdown
 switchport mode trunk

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 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 the Virtual Internet Routing Lab (VIRL) software as well. The .VIRL file found here is a file that when used with VIRL will load a lab topology similar to this lab’s topology, with the initial configuration shown in the lab as well. This section lists any differences between the lab exercise and the .VIRL file’s topology and configuration.

Download 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 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:

switchport trunk encapsulation dot1q

Network Device Info

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

Host device info:

This table lists host information pre-configured in 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: traceroute 10.1.1.1

To connect to another node within the topology: telnet 10.1.1.1