Friday, January 8, 2016

Packet Tracer 6.1 - HSRP Configuration

What is HSRP ?

HSRP (Hot Standby Router Protocol) is a redundancy protocol for setting up a fault-tolerant default gateway in a LAN environment. This is a Cisco proprietary protocol. The standard protocol is VRRP (Virtual Router Redundancy Protocol)
The primary router with the highest configured priority operates as a virtual router with a virtual gateway IP address. It responds to the ARP request from PC or servers connected to the LAN with the MAC address 0000.0c07.acXX where XX is the HSRP group ID (converted to an hexadecimal value). If the primary router should fail, the Cisco router with the next-highest priority available in the LAN segment would take over the gateway IP address and answer ARP requests with the same mac address, thus achieving transparent default gateway fail-over.

 

HSRP in Packet Tracer 6.0

HSRP is a new feature of Packet Tracer 6.0 . This protocol can be configured on every Cisco router available in Packet Tracer as well as on Cisco Catalyst 3560 layer 3 switch.
The following IOS commands are available :
  • standby  <0-4095> ip        Enable HSRP and set the virtual IP address
  • standby  <0-4095> preempt   Overthrow lower priority Active routers
  • standby  <0-4095> priority  Priority level
  • standby  <0-4095> timers    Hello and hold timers
  • standby  <0-4095> track     Priority Tracking

 

HSRP configuration using Cisco 2911 ISR routers

Packet Tracer 6.0.1 - HSRP topology example with Cisco 2901 ISR routers

Two network are configured for this tutorial :
  • Network 192.168.1.0/24
    • Router0 : 192.168.1.2 (GigabitEthernet 0/0)
    • Router1 : 192.168.1.3 (GigabitEthernet 0/0)
  • Network 192.168.2.0/24
    • Router0 : 192.168.2.2 (GigabitEthernet 0/1)
    • Router1 : 192.168.2.3 (GigabitEthernet 0/1)
Two HSRP groups are configured on the ISR routers :
  • HSRP Group 1 :
    • IP address : 192.168.1.1
    • Router0 with priority 120 (preemption enabled)
    • Router1 with HSRP default priority (100)
  • HSRP Group 2 :
    • IP address : 192.168.2.1
    • Router0 with priority 120 (preemption enabled)
    • Router1 with HSRP default priority (100)

Routers configuration

Router0 configuration Router1 configuration
interface GigabitEthernet0/0
 ip address 192.168.1.2 255.255.255.0
 duplex auto
 speed auto
 standby version 2
 standby 1 ip 192.168.1.1
 standby 1 priority 120
 standby 1 preempt
!
interface GigabitEthernet0/1
 ip address 192.168.2.2 255.255.255.0
 duplex auto
 speed auto
 standby version 2
 standby 2 ip 192.168.2.1
 standby 2 priority 120
 standby 2 preempt
interface GigabitEthernet0/0
 ip address 192.168.1.3 255.255.255.0
 duplex auto
 speed auto
 standby version 2
 standby 1 ip 192.168.1.1
!
interface GigabitEthernet0/1
 ip address 192.168.2.3 255.255.255.0
 duplex auto
 speed auto
 standby version 2
 standby 2 ip 192.168.2.1

Preemption is configured on Router0 using the standby X preempt commands. This router will always assume HSRP active state when it's online and if it has the highest HSRP priority in the network. The same configuration without the standby x priority 120 configuration on Router0 does not work and Router1 assumes the active state because it has a higher IP address configured.



Testing the configuration

Packet Tracer 6.0 - HSRP active router (ISR 2911) with preemption enabled
Packet Tracer 6.0 - HSRP standby router (ISR 2911) with 2 groups

Router0 is active for both HSRP groups. Both routers detected each other correctly but the priority seems to be wrong (Standby router is 192.168.1.3, priority 120 should be Standby router is 192.168.1.3, priority 100 on Router0)

Testing HSRP configuration is Packet Tracer 6.0.1 (ping, tracert, arp)

Ping, traceroute and arp commands issued on Laptop0 confirms that the configuration is working. The IP packets are transiting through Router0 (192.168.1.2)

Known bug

HSRP can be configured the same way on Cisco 3750 multilayer switch vlan interfaces in Packet Tracer 6.0.1.

interface Vlan100
 ip address 192.168.1.2 255.255.255.0
 standby version 2
 standby 1 ip 192.168.1.1
 standby 1 preempt
!
interface Vlan200
 ip address 192.168.2.2 255.255.255.0
 standby version 2
 standby 2 ip 192.168.2.1
 standby 2 preempt

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