how do i create 2 sub interfaces for inter vlan routing with HSRP

[tyr668]

Hi guys, 

Let's say if i have 2 vlans (vlans 10 , 20)  and i require inter vlan routing.

i want to make HSRP with standby at right side of the router (g0/1), active on router (g0/0). my configuration is to go into each subinterface (on both side g0/1.10, g0/0.10) to put in the IP for the VLAN 10 subnet and input standby IP. But when I try to input int g0/0.10 ip address 192.64.0.66/27 , it says it overlaps with int g0/1.10 ip address 192.64.0.67/27 . am i doing it wrongly ?

or how should i go about doing HSRP with inter VLAN routing in this scenario? Been pulling my hair trying to understand this scenario. if you guys were to redesign this scenario, which requires both HSRP for redundancy and inter vlan for vlan 10 and 20, how would you guys design it ? Many thanks guys.. 

[Flavio Miranda]

Hi @tyr668 

 The problem is that the address is actually overlaping and you need to use different networks

If you are using 192.64.0.64/27 on the interface Gi0/0, you need to use another network on interface Gi0/1

Next available network would be 192.64.0.96/27

int g0/1.10

ip address 192.64.0.66 255.255.255.224

int g0/1.10

ip address 192.64.0.96 255.255.255.224

If you have problems, attach your PacketTracer project and let me help you.  Zip it first

[tyr668]

Hi flavio , 

but I thought I have to use the same subnet of vlan 10 which is 192.64.0.64/27? If I’m using different subnet , will it affect my standby for vlan 10 ? Because standby must be in same subnet I suppose..

[Flavio Miranda]

Got it.

But then you need two routers. And you connect one switch to two routers.

Attach you project here and I will teach you how to do. zip it first.

[tyr668]

hi flavio , here's my packet tracer file. Thank you so much flavio

[MHM Cisco World]

you config HSRP in Router not in SW, but there is ONLY ONE ROUTER ?? you cant config HSRP with only one ROUTER and use different interface, 
You need to add another Router to your topology and config HSRP.

[tyr668]

how should i configure it let's say if i were to use switches for HSRP ? do i do SVI on both core switch or just one ?

[MHM Cisco World]

Correct 

[Flavio Miranda]

Hi @tyr668 

  Your topology is not well designed for HSRP.  I am attaching a file with another topology so that you can take a look and maybe replicate in yours.

 The idea of HSRP is to provide logicall redundancy for hosts. In order to achieve that, you need to have a switch connected to a 2 layer3 device, which can be a router or a Layer3 switch. I used a routers.

You may take a look on the file and reverte back if you have doubt or question.

You can use the command show standby on both routers to see the HSRP

and you can test by pinging from PC and disabling the router´s interface from on side and see if the pings continue as it should.

[tyr668]

hi flavio , 

thank you for your design, i've tried to understand and i hope i got it right. is my design 2 topology attached here a good HSRP design ? just want to be sure i'm on the right track. thank you 

[Flavio Miranda]

Let me see.

[MHM Cisco World]

can you share photo for new design ?

[Flavio Miranda]

Your design is functional but is not good yet. You need to think on the HSRP from the redundancy perspective.

If your layer3 switch went down you access switch will stop working as the only alternative they have is the Layer3 switch.

 The design I proposed was better because if one router went down, the VIP will be moved to the other router and clients will not get disconnected. that´s the idea of the HSRP.

This way I am offering logical and physical redundancy at Layer3 level.

[tyr668]

oh i see, just to clarify my design is not perfect because if the main router dies, all the clients will be disconnected right? 

But in a scenario where just one L3 switch dies down, will it be considered a well-designed topology? 

[Flavio Miranda]

It would if the HSRP run between the 2  layer3 switches  and if you add another link from access switch to layer3 switch.  This way your design will be as redundant as mine.