Friday 3 January 2014

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).


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

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

Router1 configuration:

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

However :
  • Laptops can't ping the HSRP IP addresses configured on the multilayer switches
  • The packets are not forwarded between the 2 laptops if the HSRP address are the default gateways configured on both pc.

No comments:

Post a Comment