13.1 FHRP – Type Protocols

What are FHRP protocols ( First Hope Redundancy Protocols )? FHRP protocols are special techniques that provide redundant default gateways for end devices, without the necessary additional end-user configuration. Using FHRP, two or more routers can share the same virtual IP address and MAC address and can act as a single virtual router. Hosts on the network are configured with the shared IP address as the default gateway. An example is the Cisco Hot Standby Router Protocol (HSRP). What is Cisco HSRP?

Cisco HSRP (Hot Standby Router Protocol) is a redundant protocol for establishing a fault-tolerant default gateway.

Table 13.1 HSRP versions

13.2 HSRP Configuration (Exercise 35).

In this exercise, we will demonstrate the idea of HSRP on routers R-AUSTIN and R-BOSTON, which serve as default gateways for hosts PC-CALIFORNIA and PC-DALLAS.

Required equipment:

 PC-PT – 2 pts

 Switch 2950-24TT – 2 pts

 Router 1841 – 3 pts

Table 13.2 Network addressing (Austin, California, Boston, Dallas)

Figure 13.1 Network topology

Step 1. Make and configure the network according to the given assumptions. Step 2. Configure RIPV1 dynamic routing correctly .

Step 3. Test the packet path from PC-CALIFORNIA to PC-DALLAS.

Figure 13.2 The path of the package goes through R-AUSTIN and R-DALLAS. Step 4. Simulate Fa0/0 interface failure in R-AUSTIN

Figure 13.3 Network topology with Fa0/0 interface failure in R-AUSTIN Step 5. Test the packet path from PC-CALIFORNIA to PC-DALLAS.

Figure 13.4 The result of the tracert command

NOTE: The default gateway in PC-CALIFORNIA is 1.1.1.2, but it has crashed, although a route through the R-BOSTON router is possible.

Step 6. Prepare the HSRP protocol configuration on R-AUSTIN. In the R-AUSTIN router, run the commands:

en

conf t

int fa0/0

standby 1 ip 1.1.1.7

standby 1 priority 110

standby 1 preempt

end

Step 7. Prepare the HSRP protocol configuration on R-BOSTON . In the R-BOSTON router, run the commands:

en

conf t

int fa0/0

standby 1 ip 1.1.1.7

standby 1 preempt

end

Figure 13.5 Messages after executing commands on the R-BOSTON router Step 8. Modify the IP protocol configuration on PC- CALIFORNIA. Set in PC- CALIFORNIA, Default gateway = 1.1.1.7

Figure 13.6 Changing the address of the default gateway in PC- CALIFORNIA Step 9. Checking the packet route from PC-CALIFORNIA to PC-DALLAS before a failure.

Figure 13.7 The path of the package goes through R-AUSTIN and R-DALLAS. Step 10. Checking the route of the packet from PC-CALIFORNIA to PC-DALLAS after simulating a failure at the Fa0/0 interface in R-AUSTIN.

Figure 13.8 The path of the package goes through R-BOSTON and R-DALLAS. Observation: Address 1.1.1.7 is the so-called default virtual gateway.

Figure 13.9 Route in case of R-AUSTIN failure

Figure 13.10 Route in case of failure R-BOSTON

13.3 HSRP Configuration (Exercise 36)

In the second example, we will demonstrate HSRP configuration on routers RTR1 and RTR3, which serve as default gateways for hosts on LAN-A and LAN-B. When configuring the HSRP protocol, a virtual gateway will be created that uses the same default gateway address for hosts on both LANs

Figure 13.11 Network topology

If one gateway router becomes unavailable, the other router will take over using the same default gateway address that was used by the first router. Since the hosts on the LANs are configured with the virtual gateway's IP address as the default gateway, the hosts will regain connectivity to the remote networks once the remaining router is activated by HSRP.

Required equipment:

 Server-PT – 1 pts

 PC-PT – 2 pts

 Switch 2960-24TT – 2 pts

 Router 2911 –3 pts

Table 13.3 Network addressing (RTR1, RTR2, RTR3, SW1, SW2)

Table 13.4 Routing configuration parameters for RTR1

Table 13.5 Routing configuration parameters for RTR2

Step 1. In RTR2, make default-information originate

Table 13.6 Routing configuration parameters for RTR3

Step 2. Make and configure the network according to the given assumptions. Step 3. Check the path of the package from PCA to SVR

Figure 13.12 The path of the packet from PCA to SVR

Step 4. Check the path of the package from the PCB to the SVR Step 5. Configure HSRP on the LAN interface G0/1 RTR1.

enable

conf t

interface Gi0/1

standby version 2

Step 6. Configure the IP address of the virtual default gateway. Comments:

This address must be configured on all hosts that require default gateway services. It replaces the physical address of the router interface that was previously configured on the hosts.

Multiple HSRP instances can be configured on a router. You must specify an HSRP group number to identify the virtual interface between routers in the HSRP group. This number must be consistent between the routers in the group. The group number for this configuration is 1.

standby 1 ip 192.168.1.254

Step 7. Designate an active router for the HSRP group .

Comments:

This is the router that will be used as the gateway device unless it fails or the path to it becomes inactive or unusable. Specify the router's interface priority. The default value is

100. A higher value will determine which router is the active router. If the priorities of the routers in the HSRP group are the same, the router with the highest configured IP address will become the active router.

standby 1 priority 150

Comments:

RTR1 will act as the active router, and traffic from the two LANs will use it as the default gateway.

Step 8. If it is desirable for the active router to resume this role when it becomes available again, configure it with the preempt option. The active router will take over the role of the gateway when it is operational again.

standby 1 preempt

Step 9. Configure RTR3 as a standby router (Configure RTR3 interface connected to LAN-B).

standby version 2

standby 1 ip 192.168.1.254

Step 10. Check the HSRP configuration in RTR1.

show standby

Step 11. Check the HSRP configuration in RTR3.

show standby

Step 12. Check the summary of HSRP statuses in RTR1.

show standby brief

Step 13. Check the summary of HSRP statuses in RTR3.

show standby brief

13.4 List of auxiliary files

 exercise35-hsrp.pkt

 exercise36-hsrp.pkt