Network Design, Questions on HSRP ... and DHCP

[markrichards1471]

Hi Everyone, 

I'm redesigning our network at Company HQ, this design will likely be rolled out across 3 or 4 other admin sites. Our routers are connected to a BT provided MPLS network (Corporate WAN with BGP). BT will be configuring HSRP on the routers, its a managed service and so they config the CE equipment. 

My question is mainly around the HSRP, I have designed redundancy into the physical LAN. But how should the HSRP be configured, (BT will be doing the config on this, but I want to know for my own knowledge what the best way to do it is) I had thought about 2 HSRP groups (one for of the router interfaces) shared over the 2 routers.... the problem I see with this is the connectivity for the end user devices and VLANS on the L3 distribution layer switches.

I'm thinking now, that maybe having 2 HSRP routers and 2 x Active HSRP IP's is not such a problem, would I simply configure group 1 standy IP as the primary default route on the switches and Standby 2 a the secondary default route on the Switches?

Regarding the 4 x VLAN's I will configure on the Switches, normal config of the Vlan Interface being the default router, the the switch routing the traffic out toward the primary (or secondary) default route.

We are also going to have to have the switches issue the DHCP for now, I guess All I can do with this config (NO SERVERS ONSITE...ALL in AZURE) is get the 2 x Switches to dish out the DHCP ...for Now until we have some Local DC's...  

Maybe have 2 IP Pools on each switch for the 4 vlans ?

Help is very much appreciated on this design,

[Jaderson Pessoa]

@markrichards1471 Hello,

I'm thinking now, that maybe having 2 HSRP routers and 2 x Active HSRP IP's is not such a problem, would I simply configure group 1 standy IP as the primary default route on the switches and Standby 2 a the secondary default route on the Switches?

A1 : Yes, this can be a way, but it will limit you case of you need change something in your enviromnet, like.. new site, new network separated.  In this case i will suggest to you use a dynamic routing like ospf or eigrp. You can control the flow of your routing using P2P or DR in case of OSPF and will not necessary create HSRP to ROUTERS.

A2: I'll suggest to create using HSRP in your DISTRIBUTION LAYER:

Maybe have 2 IP Pools on each switch for the 4 vlans ?

A1: I've created a article about this... there are some consideration until do it. Look below links about my explanation.

https://community.cisco.com/t5/documentos-de-geral/automa%C3%A7%C3%A3o-de-deploy-dhcp-em-ambientes-usando-hsrp/ta-p/3954914

[markrichards1471]

Thanks for the input Jaderson, Unfortunately I cannot create HSRP on the Distribution layer instead of the Core...

BT are providing a managed service and HSRP is the offering they will be configuring on the routers (we don't have any admin privileges on the routers).

To be clear, my main problem is I believe I will need 2 x HSRP Groups (for the 2 LAN interfaces on each Router, 4 interface over 2 routers as 2 x HSRP Groups) I'll need to split the traffic for data and voip to HSRP group 1 and HSRP group 2. 

For the DHCP I will have to again run 2 x DHCP Servers, 1 on each L3 Switch ... not ideal but until we have some onsite Windows servers we will have to do it this way! 

All my inter vlan routing will be done at the Distribution layer, routing data to HSRP group 1 and voip to HSRP Group 2 .....   

I don't see another way to do this..... BIG Problem here is will the traffic take an indirect route to the HRSP interface ? 

Wondered if anyone can take a look at my network design in the pdf and advise on a logical design for this.

Thanks