HSRP - VLANs - ROAS - Two core switches

[ameneghinello]

Hi everybody,

first of all I want to thank you for the help you can give me. Following I will describe my problem with a network setup.

I've to build a new network using the simulator Packet Tracer (PT) to test some network behaviours before implement it. The network is a classic two-tier design with one access switch on each floor of the building and two core switches (fault-tollerance issue) places in the data center.

The two core switches will be linked with two router that provide MPLS connectivity to the site; I will have to implement the HSRP to have routing fault-tollerance on the site.

The network is composed by different VLANs to support different issues and reduce the broadcast domains. I will create different standby domain to have load balancing between routers for the different VLANs.

data center devicesIn the above picture there is highlighted my problem. To have full tollerance I will have to connect my core switches to each router on different interfaces, when I have to configure the sub-interfaces on the Router I will have to assign them an IP on the same network, example:

• Router PRImary:
  • interface FastEthernet0/1.10
    • ip address 192.168.1.2 255.255.255.0
    • standby 1 ip 192.168.1.1
• Router Backup:
  • interface FastEthernet0/1.10
    • ip address 192.168.1.3 255.255.255.0
    • standby 1 ip 192.168.1.1 

My knoledge says that (on router PRImary) in the interface FastEthernet0/2.10 I couldn't assign an IP address on the 192.168.1.0/24 network. How can I achive my target? So the problem is how I can assign two interfaces of the same router to the same VLAN to support HSRP.

Thanks

[Mike-]

One way with L3 switches is VSS Virtual Switching System/MEC(Multi-chassis EtherChannel) these commands may not be available on your switch. 

https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Campus/VSS30dg/campusVSS_DG/VSS-dg_appa-configs.pdf

[shaps]

You would normally have a layer 2 device between the routers and the L3 device, you could utilise the 2960 for that purpose and vlan it through to the routers or the 3750 for that matter.
The way it is set up now I am guessing is p2p links from the L3 switch, you need a L2 path between the routers in order for HSRP to work.

[brselzer · Accepted solution]

Hello,

There are a couple different options you have depending on what the platform you are going to use. These technologies might not be supported in packet tracer:

EVCs - Make the interfaces L2 and configure a BDI much like you would configure an SVI
https://www.cisco.com/c/en/us/td/docs/routers/asr920/configuration/guide/ce/b_ce_xe-313s-asr920-book/b_ce_xe-313s-asr920-book_chapter_01.html

mLACP - Multichassis-etherchannel. Connect two ASRs into the same port-channel so they seem like one device to the downstream switch.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/cether/configuration/15-0s/ce-multichass-lacp.html

IRB Bridging on older platfroms - Put two interfaces into the same bridge group so they can be in the same subnet. Not supported on newer models. Should use EVCs instead. 

https://www.cisco.com/c/en/us/support/docs/lan-switching/integrated-routing-bridging-irb/17054-741-10.html#irbconfig

Unfortunately, packet tracer might not be advanced enough to simulate these technologies so you will have to figure out what platforms you are going to use and what technologies they support.

Hope that helps!

[ameneghinello]

Thank you very much.

One more question: what simulator can I use to create a virtual lab of my network?

[brselzer]

Hello,

There are a couple that have their pros and cons. Each one will probably have some limitations depending on the technology you are trying to simulate:

GNS3 - https://www.gns3.com/

VIRL - http://get.virl.info/index.php

EVE - https://www.eve-ng.net/

There are probably even more but these are the ones I am aware of. 

Hope that helps!