Is it possible to set up HSRP-HSRP WANs with active/active LANs?

[springzone]

Hello all,

Is it possible to have the LAN active active, the Lower LAN will also pass traffic via the Upper LAN where teh HSRP is active and vice versa via a cross connect between? If yes? should it be layer 2 or 3 or which is most desirable? avoiding loop as well. May I have a sample configs on both RED Upper and RED Lower routers?

Thank you.

FRS :)

[Georg Pauwen]

Hello,

not sure if I understand your question...

HSRP doesn't do load balancing, VRRP does. So that means that with HSRP you cannot have active/active. VRRP is usually the viable alternative...

[Julio E. Moisa]

Hi

You cannot have HSRP active - active (secondary device) although it can be seen on both devices it will not work as desired, so if you want that scheme I recommend GLBP to have load balance.

Hope it is useful

:-)

[springzone]

Hi all,

I apologize for not making it clear.

It will be a active/standby HSRP facing another HSRP on the WAN side. It is expecting traffic to flow from both LANs to the Active HSRP. The 2nd router traffic of the Standby HSRP is expecting to flow towards the Active HSRP router via a cable connected/linked between both routers. How do we ensure the 2nd router receives the expected routes for the return traffic to flow to the expected Active HSRP router WAN? 

Pardon me my explanation is bad.

Thanks

[Hector Gustavo Serrano Gutierrez]

Hi springzone,

"How do we ensure the 2nd router receives the expected routes for the return traffic to flow to the expected Active HSRP router WAN? "

Answer:

Using HSRP you can decide which Router will be in charge of forwarding the traffic to the WAN. As you are probably already aware, this will be the HSRP "Primary Router" as long as the hosts on the LAN use the HSRP Virtual IP address as Default Gateway of course.
What HSRP does not do is to take care of the return traffic. This must be engineered on a per case basis.

Therefore, the possibility of "Asymmetric Routing" exists. This is, traffic can be sent to the WAN using "Router A" but the response can return on "Router B".

It is not quite clear to me your network diagram.

In the below scenario, the communication will be:

• PC_A > R1 > R3 > PC_B
• PC_B > R4 > R2 > PC_A

You only need to ensure the Routers involved know PC_A and PC_B networks using either an IGP (EIGRP or OSPF) or with Static Routes.

HSRP

HTH.

[CiscoBrownBelt]

So how about doing harp with two nexus 9k in a vpc domain set to the same priority?