[c-nsp] Load balancing across 2 ADSL lines

[Ryan O'Connell]

On 13/10/2005 14:56, James O'Farrell wrote:

>Thanks for the info.
>
>In regards to HSRP I have seen this;
>http://www.cisco.com/en/US/tech/tk648/tk362/technologies_configuration_example09186a0080094e90.shtml 
>which used 2 x instances of HSRP to load balance.
>
>Unfortunately I am getting 2 ADSL lines from 2 Different ISP's so multilink and any routing trickery is out.
>  
>

In that case, your only options are HSRP or per-destination load 
balancing - which will almost certainly give you poor traffic 
distribution - or two tunnels to a remote router and load-balancing 
per-packet across the tunnels.

If the ADSL lines are from 2 different ISPs, you'll get an outage when 
either of them dies until you delete one from the config unless you run 
a routing protocol across tunnels or similar - you may find you lose 
reliability this way, rather than gaining it which I guess is your aim. 
ISDN dialup as a backup to ADSL may be a better choice if you need 
reliability.