[c-nsp] VPN failover / load sharing using IOS?

Wed Feb 9 01:18:40 EST 2005

Actually, your right. But really the vpn is establishing a single  
source host to a single destination host, since whats really riding on  
top of the GRE layer is the VPN itself.  Like you say, per destination  
balancing sort of makes it not work very well.

Too bad cisco doesn't allow you to just define two vpn's and treat the  
result as two equal paths, that would be a bit better.

Brian

On Feb 8, 2005, at 11:59 PM, Luan Nguyen wrote:

> It would work just like that I think.  The router would just do
> per-destination load share wouldn't it - unless you only have one host
> talking to one host?  In our environment we have one spoke with dual  
> GRE
> tunnels to 2 hubs with equal cost.  Yours is a little different but it
> should work for load balancing just like that.
>
> Luan
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Brian Feeny
> Sent: Wednesday, February 09, 2005 12:33 AM
> To: Rodney Dunn
> Cc: Cameron.Dry at didata.com.au; cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] VPN failover / load sharing using IOS?
>
>
> Rodney,
>
> I will definitely look into OER.  But if I had 2 GRE tunnels, why can't
> I just point statics like in my example, for each remote subnet down
> the tunnels?  Wouldn't that load balance AND work for failover?
>
> Thanks,
>
> Brian
>
> On Feb 8, 2005, at 11:20 PM, Rodney Dunn wrote:
>
>> There are really on two ways to do this:
>>
>> a) you announce some subset of routes down
>>    one gre tunnel from the headend and prefer
>>    them and the other subset over the backup tunnel
>>
>> that way if one tunnel goes away you will have failover.
>> The drawback there is the load sharing isn't dynamic.
>>
>> The only way you can get dynamic loadsharing in
>> this type of setup is OER.
>>
>> b) Do OER at the spoke side and let it load balance
>>    the traffic back towards the headend.
>>
>> They were going to put a sample of that in the OER
>> deployment guide but I'm not sure they have gotten
>> to it yet.
>>
>> http://www.cisco.com/go/oer
>>
>> Rodney
>>
>>
>>
>> On Tue, Feb 08, 2005 at 10:31:43PM -0600, Brian Feeny wrote:
>>>
>>> thanks, although that looks to be for sites with multiple routers and
>>> multiple links.  Each of these sites is only going to have one  
>>> router,
>>> that takes in 2 T1's.  I don't think that will work in that scenrio.
>>>
>>> Brian
>>>
>>> On Feb 8, 2005, at 10:07 PM, Cameron.Dry at didata.com.au wrote:
>>>
>>>> Check out:
>>>>
>>>> http://www.cisco.com/en/US/products/sw/iosswrel/ps5012/
>>>> products_feature_
>>>> guide09186a00800ed370.html
>>>>
>>>> Cameron
>>>>
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: cisco-nsp-bounces at puck.nether.net
>>>> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of
>>>> signal at shreve.net
>>>> Sent: Wednesday, 9 February 2005 11:50 AM
>>>> To: 'cisco-nsp'
>>>> Subject: [c-nsp] VPN failover / load sharing using IOS?
>>>>
>>>>
>>>> Has anyone done any type of VPN failover and/or load balancing using
>>>> IOS?
>>>>
>>>> For example something like a 2 1700 routers, each with 2 T1 cards in
>>>> them,
>>>> Each T1 card would be connected to a different ISP, each with its  
>>>> own
>>>> IP space
>>>> (no BGP).  Either T1 would be able to go down, and the VPN could
>>>> re-establish
>>>> itself over the remaining T1.  Both T1's would be load balanced over
>>>> for VPN
>>>> connectivity.
>>>>
>>>> Is it possible to establish 2 VPN's, 1 over each link, with the same
>>>> source/destination private networks defined, and have the router  
>>>> load
>>>> balance these and also work in failover?
>>>>
>>>> Another thought, which is kind of ugly (but maybe not), is 2 GRE
>>>> tunnels, and then dual static routes over the tunnels:
>>>>
>>>> Router 1 T1 #1  <----------------------- GRE Tunnel #1
>>>> -------------------> Router 2 T1 #1
>>>> Router 2 T1 #2 <------------------------ GRE Tunnel #2
>>>> -------------------> Router 2 T1 #2
>>>>
>>>> ip route <insert vpn endpoint ip> 255.255.255.255 Tunnel1
>>>> ip route <insert vpn endpoint ip> 255.255.255.255 Tunnel2
>>>>
>>>> Then establish the VPN on top of the above.  I don't particular like
>>>> the idea of building a tunnel on top of 2 other tunnels, so if  
>>>> anyone
>>>> has experience in doing this type of setup, please share what you
>>>> used
>>>> to do it.
>>>>
>>>> Brian
>>>>
>>>>
>>>>
>>>> Brian Feeny, CCIE #8036, CISSP
>>>> Network Engineer
>>>> ShreveNet Inc.
>>>>
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>>>
>>> Brian Feeny, CCIE #8036, CISSP
>>> Network Engineer
>>> ShreveNet Inc.
>>>
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