I have attached a diagram, but here is the description:
Putting 2 x 2821 in a datacenter, they are providing 2 ethernet cables for WAN/Internet with a single default gateway for us to route our traffic to.
Behind my 2 x 2821 I have a publicly routable (provided by the datacenter) /24.
The DC will be routing all traffic to our /24 to an IP within an interconnect block.
The equipment that will be hosted will be Citrix, http, etc. So basically inbound connections into the datacenter from the internet.
The 2821's will also be VPN terminators for a variety of VPN's that will be used to access resources within the data center.
My plan is to use HSRP for my WAN ports to create a single Virtual IP within the interconnect block which the datacenter will then route our /24 routable subnet to. So basically according to my diagram (ips replaced) my WAN interconnect HSRP IP will be 184.108.40.206, and they will route all traffic for my 220.127.116.11/24 network to 18.104.22.168.
My question is, is using HSRP on my WAN side (as outlined above) a valid design? Or should I be looking at seeing if the datacenter can use routing protocols and my 2821's to achieve high availability/redundancy?
A 2821 will practically support only about 50 Mbps.
Yes, you can have all participating routers in the same subnet.
Thank you for the nice rating and good luck!
in your specific case HSRP could be used because what you call WAN links are actually GE or FE links.
However, looking for the use of a routing protocol is a better choice because the intermediate Layer2 devices makes not possible to detect a failure directly, that is even if both routers are powered off for other 4 hours (default ARP timeout) the DC routers will try to send traffic to your VIP 22.214.171.124.
you and the DC should implement IP SLA to track effective reachability of next-hops. that is a complex configuration to try to emulate a routing protocol.
Using dynamic routing protocol provides better detection and should be preferred because it allows for load balancing over both paths/routers.
deploy two point-to-point subnets /30 to connect DC1 to R1 and DC2 to R2 and you should be fine.
intermediate switches to introduce IPS are not a problem with a routing protocol there are hello messages that track neighbor health for you.
Hope to help