Cisco Router Redundancy

Posted on 2007-10-06
Last Modified: 2008-01-09
i have a cisco 2801 router, this is the only router we got.

if i have another router - exact same model, is there a way to setup redundancy on the router for failovers, so that if the primary router fails , the backup kicks in automatically !!

Question by:rdvarghese
    LVL 79

    Accepted Solution

    Yes, with HSRP (Hot Standby Router Protocol). No if you don't have redundant WAN connections, too.
    It also depends on other services that you may have running like VoIP gateway or something else, and what, if anything, is between the router and the rest of the LAN.


    Author Comment

    between the router
    there is a cisco ASA 5510 firewall
    and 3 cisco catalyst switches.

    can the firewall and switches be setup for redundancy? meaning if i purchased an additional ASA and 3 more switches?

    LVL 2

    Assisted Solution

    The ASA can be paired with another in high-availability mode which provides automated failover. The question now is what is "upstream" of the ASA?

    Switching is a different matter - with 3 switches you could use spanning tree protocol to provide redundant pathways between two of the switches in the event the intermediary switch fails. If you lose a switch however, you still lose connectivity to hosts connected to that switch.
    LVL 79

    Expert Comment

    Yes, you can have redundant everything, but it can get sticky in getting everything configured just right.
    ASA can be either active/standby or active/active
    If you have redundant switches, are all of your hosts/servers dual homed to different switches? You have to determine where redundancy makes sense and where it is just a hinderance.
    LVL 2

    Expert Comment

    I agree with lrmoore on this - providing high availability across your network can get very messy if it isn't planned meticulously. I would recommend you bring in an external consultancy to assess you network and needs. You'll usually get a decent price for this sort of consultancy since they're banking on the knock on consultancy and hardware sales out of it.

    You should get a report of your network with regards to redundancy and then have a meeting to discuss what you feel your requirements are and where this fits in with your budget.Some elements are trivial to provide redundancy for but others will require a considerable amount of time and effort.

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