[cisco-bba] LNS redundancy

[Arie Vayner]

For PPPoE, you can make sessions hit both BRAS devices at the same time. The
PADI is a broadcast, so would reach all of them.
Each one will send a reply (PADO) in unicast, but only 1 will be the 1st
one, and will be used.
Statistically, the load will split because of CPU and load on the devices.

Alternatively, there is a way to introduce a delay on a specific BRAS for
PADO, so it will be less preferred.

Arie

On Wed, Mar 23, 2011 at 11:43 AM, Hitesh Vinzoda
<vinzoda.hitesh at gmail.com>wrote:

> Hi Arie,
>
> Could you please tell me how the first hop redundancy for pppoe clients
> would be achieved?
>
> Regards
>
> Hitesh
>
> On Wed, Mar 23, 2011 at 4:33 PM, Arie Vayner <ariev at vayner.net> wrote:
>
>> Just ask the Telco to open L2TP tunnels to both LNSs. They can configure
>> them as active/active (split the users on both LNSs) or active/passive
>> (depends on the LAC vendor...)
>>
>> Arie
>>
>> On Wed, Mar 23, 2011 at 9:26 AM, Hitesh Vinzoda <vinzoda.hitesh at gmail.com
>> > wrote:
>>
>>> Hi,
>>>
>>> I m trying to achieve redundancy for gateway of pppoe adsl clients on
>>> LNS. My scenario is as below.
>>>
>>> > Telco LAC sends the PPPOE session to our LNS using L2TP to LNS. It
>>> sends it to Primary LNS at all the time till the Primary LNS is alive.
>>> > If primary LNS fails than Telco LAC creates tunnel to secondary tunnel.
>>> All connections are teared down and sent to secondary LNS.
>>> > Since we know that gateway or default route configured on ADSL PPPoE
>>> clients needs to unique as these are the attributes sent out by Radius or
>>> DHCP and configured manually
>>> > So in case if primary LNS fails than the IP address on virtual template
>>> on LNS should be available to PPPOE clients. I tried different ways to
>>> achieve this
>>>
>>> 1. HSRP on virtual-template interface is not supported.
>>> 2. If i use internal physical interface on both LNS and run HSRP, while
>>> having ip unnumbered fa0/0 under virtual-template configuration. The virtual
>>> template takes the physical ip address instead of virtual ip.
>>>
>>> Lastly i thought of having anycast to have resue the situation.
>>>
>>> > Configured loopback interfaces on both the LNS with the same ip address
>>> 20.20.20.1 and ip unnumbered command under virtual-template interface. This
>>> works like charm.
>>>
>>> I m just wondering that is my solution correct or justifies the ISP LNS
>>> scenario? or what are other methods to achieve redundany in LNS for gateway
>>> ip address of pppoe.?
>>>
>>> Thanks in advance
>>>
>>> Hitesh
>>>
>>> _______________________________________________
>>> cisco-bba mailing list
>>> cisco-bba at puck.nether.net
>>> https://puck.nether.net/mailman/listinfo/cisco-bba
>>>
>>
>>
>
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