In part 2 of the HSRP series I will cover the configuration & show you how to verify the configuration.

I have put together a Microsoft® Visio® diagram which shows you a lot more than simply Hot Standby Router Protocol (HSRP). You need to concentrate on Hot Standby Router Protocol (HSRP)

configuration alone and at a very high level look at the diagram and think about "High availability".




The key to this lab would be to ensure without any administrative overhead i.e. changing of default gateways on any device including the desktops, configuration of new routers etc...achieve end to end connectivity!!!

I shall not cover all of the topics in depth and focus primarily only on Hot Standby Router Protocol (HSRP) but I will touch on the other things slightly and try to cover different bits in the future articles on the similar diagram.

But the key is to keep in mind is "High availability".

1. All 3 LANS have two paths to reach the Head Office & vice versa.

2. Equal cost load balancing can be achieved in this scenario by using various protocols. Note: for an example please refer to the ISP rotuer config attached below at the end of this article.

3. Resilience for your LAN users using Hot Standby Router Protocol (HSRP) on each site to access resources located at the Head Office.

4. If something goes wrong at a specific POP at the service provider (SP) OR the router on that link the alternate Serial link can be utilized from a different service provider (SP) at an entirely different POP to reach the Head Office.

5. If both Serial Links between each site is not an affordable solution to be utilized simultaneously the (second serial link can be on contract on a per (MB) utilization contract) than you can manipulate the metric in such a way that only (1 serial link) is utilized at any given time and the second path is injected into the routing table only when the primary route is not available and the secondary link will be used purely for redundancy.

6. "High availability" can be also considered at places like HO for the switches which plug-in to the servers to ensure if one of the switches fail the servers can use there fail-over connection network interface card (NIC 2) to secondary switch & still provide a successful connection to all user sessions.

The above might seem a lot of information & confusing for a few reading this article but because we are actually implementing Hot Standby Router Protocol (HSRP) for the primary purpose to ensure "High availability" is achieved for users on the LAN at each remote office & HO users, so they can access "resources" at Head Office 24 * 7.

I did not want to simply give a basic diagram of two routers / switches and complete this article, the idea was to give you an enterprise diagram and give you the feel of what can be achieved and the benefits in a multi site environment.

Finally it is time for some hands on J

Now lets start the configuration what we have all been waiting for: :)

1. Enable HSRP group & virtual ip add:

R1(config-if)#standby ?
  <0-255>                  group number
  authentication            Authentication
  delay                        HSRP initialisation delay
  ip                             Enable HSRP and set the virtual IP address
  mac-address            Virtual MAC address
  name                        Redundancy name string
  preempt                   Overthrow lower priority Active routers
  priority                     Priority level
  redirect                    Configure sending of ICMP Redirect messages with an HSRP virtual IP address as the gateway IP address
  timers                       Hello and hold timers
  track                        Priority tracking
  use-bia                     HSRP uses interface's burned in address
  version                     HSRP version

R1(config-if)#standby 12 ?
  authentication      Authentication
  ip                            Enable HSRP and set the virtual IP address
  mac-address         Virtual MAC address
  name                      Redundancy name string
  preempt                 Overthrow lower priority Active routers
  priority                  Priority level
  timers                    Hello and hold timers
  track                      Priority tracking

R1(config-if)#standby 12 ip 10.10.10.100


2. Define the HSRP Priority:

R1(config-if)#standby 12 priority 150

Note: As discussed in Part 1 the default priority is (100)


3. Enable Preempt.

R1(config-if)#standby 12 preempt

4. Define HSRP group name.

Default: HSRP has a way to define the name by default. Example: [ IP redundancy name is "hsrp-Et0/0-12" (default) ] Et0/0 = the interface we are activating Hot Standby Router Protocol (HSRP).

R1(config-if)#standby 12 name ?
  WORD  name string

R1(config-if)#standby 12 name HO-LAN-DG    

5. Enable Tracking & the decrement value for the tracked interface.

R1(config-if)#standby 12 ?            
  authentication  Authentication
  ip                        Enable HSRP and set the virtual IP address
  mac-address       Virtual MAC address
  name                  Redundancy name string
  preempt             Overthrow lower priority Active routers
  priority               Priority level
  timers                 Hello and hold timers
  track                  Priority tracking

R1(config-if)#standby 12 track ?
  <1-500>                    Tracked object number
  Async                         Async interface
  BVI                            Bridge-Group Virtual Interface
  CDMA-Ix                  CDMA Ix interface
  CTunnel                     CTunnel interface
  Dialer                         Dialer interface
  Ethernet                     IEEE 802.3
  Lex                            Lex interface
  Loopback                  Loopback interface
  MFR                         Multilink Frame Relay bundle interface
  Multilink                    Multilink-group interface
  Port-channel              Ethernet Channel of interfaces
  Serial                         Serial
  Tunnel                       Tunnel interface
  Vif                             PGM Multicast Host interface
  Virtual-PPP               Virtual PPP interface
  Virtual-TokenRing     Virtual TokenRing


R1(config-if)#standby 12 track serial ?
  <0-6>  Serial interface number

R1(config-if)#standby 12 track serial 1/0 ?
  <1-255>  Decrement value
  <cr>

R1(config-if)#standby 12 track serial 1/0 60


6. Verify the configuration.

R1(config-if)#do sh run int e 0/0          
Building configuration...

Current configuration : 210 bytes
!
interface Ethernet0/0
 ip address 10.10.10.1 255.255.255.0
 full-duplex
 standby 12 ip 10.10.10.100
 standby 12 priority 150
 standby 12 preempt
 standby 12 name HO-LAN-DG
 standby 12 track Serial1/0 60
end

R1#sh standby
Ethernet0/0 - Group 12
  State is Active
    2 state changes, last state change 00:01:28
  Virtual IP address is 10.10.10.100
  Active virtual MAC address is 0000.0c07.ac0c
    Local virtual MAC address is 0000.0c07.ac0c (v1 default)
  Hello time 3 sec, hold time 10 sec
    Next hello sent in 1.612 secs
  Preemption enabled
  Active router is local
  Standby router is 10.10.10.2, priority 100 (expires in 7.140 sec)
  Priority 150 (configured 150)
    Track interface Serial1/0 state Up decrement 60
  IP redundancy name is "HO-LAN-DG" (cfgd)


R2#sh run int e 0/0
Building configuration...

Current configuration : 185 bytes
!
interface Ethernet0/0
 ip address 10.10.10.2 255.255.255.0
 full-duplex
 standby 12 ip 10.10.10.100
 standby 12 preempt
 standby 12 name HO-LAN-DG
 standby 12 track Serial1/0 50
end

R2#sh standby     
Ethernet0/0 - Group 12
  State is Standby
    1 state change, last state change 00:03:10
  Virtual IP address is 10.10.10.100
  Active virtual MAC address is 0000.0c07.ac0c
    Local virtual MAC address is 0000.0c07.ac0c (v1 default)
  Hello time 3 sec, hold time 10 sec
    Next hello sent in 1.624 secs
  Preemption enabled
  Active router is 10.10.10.1, priority 150 (expires in 7.060 sec)
  Standby router is local
  Priority 100 (default 100)
    Track interface Serial1/0 state Up decrement 50
  IP redundancy name is "HO-LAN-DG" (cfgd)

Debugging HSRP

debug standby
debug standby errors
debug standby events
debug standby events terse
debug standby events track
debug standby packets


That is all you need to get your HSRP configured a few commands and you are in business.

You can simply now configure your entire Head office to point to [ 10.10.10.100 ] as there default gateway.

For other HSRP config for R3 / R4 / R5 / R6 you will find them in the config files attached at the end of this article.

Now you can simulate this entire lab on your desktop using dynagen. You will find at the end of this article all the files including the show outputs and the dynagen file for running this lab successfully.

Good Luck :)