[c-nsp] Load balancing across 2 ADSL lines

[James O'Farrell]

Hi,

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.

Regards

-----Original Message-----
From: Kristofer Sigurdsson [mailto:kristo at ipf.is] 
Sent: 13 October 2005 11:53
To: James O'Farrell
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Load balancing across 2 ADSL lines

Hi,

See comments inline...

On Thu, 2005-10-13 at 11:53 +0100, James O'Farrell wrote:
> Hi All,
> 
>  
> 
> I am looking to load balanced across 2 ADSL lines either both coming
> into the same router or using 2 separate routers, any thoughts would be
> much appreciated.
> 
>  
> 
> So far I have looked at;
> 
>  
> 
> HSPR;
> 
> If I understand HSRP correctly I will have to give out 2 default
> gateways which I would not like to do.

Not entirely true.  One default gateway, but two routers, using seperate
IP addresses, will negiote between themselves who has the (third) IP 
address designated as the default gateway.  This, however, is not a load
balancing method, is is primarily useful for redundancy (if a router 
goes down, the other takes over).

> 
>  
> 
> NAT;
> 
> I could have 2 WIC cards and NAT across both the ADSL links, but from
> what I have seen the 2nd line would only be used when there are no
> available translation paths on the 1st.

True...

> 
>  
> 
> OER;
> 
> >From what I can see this appears to achieve the best load balancing. Has
> anyone ever used OER, and if so is there anything I should be looking
> out for?

I have no experience with OER.

How is the ADSL terminated?  If you are terminating it yourself, you 
could use routing protocols such as OSPF to load balance the traffic.
If the ADSL is terminated on another provider's system, you could use 
tunnels to the endpoint and load balance over the two tunnels, using
routing protocols.

-- 
Kristófer Sigurðsson           Tel: +354 414 1600
Netrekstur/Network Operations  IP Fjarskipti ehf.



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