HSRP Configuration

amar007inus · ‎10-11-2007

Hi All,

Here i have configured VLANs between two Cisco 4507R switches...My team lead is asking me to configure HSRP between the VLANs....Cany anybody suggest me,,why do we need HSRP here and Let me know how to Configure HSRP.

Thanx

Amar.

ankbhasi · ‎10-11-2007

Hi Amar,

Lets say you have not configured HSRP as of now. So what you will do to configure gateway for your machines which exist on some vlan on your Cat4k switch? You will assign gateway ip address on your machines what you configured for your vlan interfaces correct.

Now lets say your vlan interface went down for some reason or lets say your whole cat4k is down now then what will happen as your machines gateway point to vlan interface ip address on your cat4k which is down now so they will not be able to reach out from their network.

Now if you configure HSRP you configure something known as virtual ip address on your vlan interfaces. The virtual ip address remains same on both the vlan interfaces which you confgure on your cat4k and that virtual ip address you will assign as your gateway address on your machines. In this way even if you 1st 4k is down your second cat4k still have that virtual ip adress and your machines will be able to reach out of their network.

So basically HSRP provides you gateway load balancing and redundacy. I tried to explain taking very simple example.

To reach more about HSRP and how to confgure have a look at this link

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ics/cs009.htm

http://www.netcraftsmen.net/welcher/papers/hsrp.htm

Please come back if you have any doubts.

HTH

Ankur

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amar007inus · ‎10-11-2007

Hi Ankur,

Its really good..But here i have 4 VLANs on 2 Cat4507R switches.So,he has given 4 seperate ips(192.168.65.252 -- HSRPa ,192.168.66.252 -- HSRPa ,192.168.67.252 -- HSRPa ,192.168.68.252 -- HSRPa) for 4 VLANs...I dont understand..can u explain me....As u said,,,we dont require that many IPs for configuring HSRP,,So how to configure

Thanx

Amar.

nathancielieska · ‎10-11-2007

Amar,

You will need 2 real ip addresses and 1 virtual ip address for each vlan

So here is an example

Switch 1

Interface vlan 5

ip address 192.168.65.252

standby 5 ip 192.168.65.254

standby 5 preempt

stadnby 5 priority 150

Switch 2

Interface vlan 5

ip address 192.168.65.253

standby 5 ip 192.168.65.254

stadnby 5 preempt

So you have a real ip address for each interface(192.168.65.252, 192.168.65.253) and then a virtual (192.168.65.254). Your virtual will be your default gateway on your hosts and will allow hosts send network traffic to whatever switch has control of the virtual ip address.

With that said you really need to be given 3 ip addresses PER VLAN (2 Reals and a virtual). For a total of 12 ip addresses (4 Vlans x 3 ip addresses).

Obviously there are other commands to run but the ones above should get you started per vlan.

Regards

amar007inus · ‎10-11-2007

Ankur,

Here it goes like...I have two Cisco4507R swicthes ...

192.168.65.0/24 - Application Server VLAN 1025

192.168.65.252 - HSRPa

192.168.65.253 - HSRPb (Future)

192.168.65.254 - HSRP VIP

192.168.66.0/24 - Tlelphony Server VLAN 1026

192.168.66.252 - HSRPa

192.168.66.253 - HSRPb (Future)

192.168.66.254 - HSRP VIP

192.168.67.0/24 -Citrix/Terminal Server VLAN 1027

192.168.67.252 - HSRPa

192.168.67.253 - HSRPb (Future)

192.168.67.254 - HSRP VIP

192.168.68.0/24 - Database Servers VLAN 1028

192.168.68.252 - HSRPa

192.168.68.253 - HSRPb (Future)

192.168.68.254 - HSRP VIP

ankbhasi · ‎10-11-2007

Hi Amar,

Your ip design looks fine to me. You need to assign your HSRP virtual ip to your clients in that respective vlans.

Also Nathan had guided you the configurations need to be done for HSRP so incase you are stuck come back again.

Also if you want you can make your 1st cat4k active for 2 vlans (1025 & 1026) and 2nd cat4k standby for those vlans and 2nd cat4k active for another 2 vlans (1027 & 1028) and 1st cat4k standby for those 2 vlans. You just need to play with priority in HSRP configuration to decide which switch should be active for which vlans.

Incase if you want or else you can keep 1st cat4k active for all vlans and 2nd standby for all vlans but good use of resources is to have load balancing also. But again as per your network requirement.

Please come back if you have any doubts.

HTH

Ankur

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