[cisco-bba] LNS redundancy

[Arie Vayner]

For PPPoE redundancy, if a BRAS fails, the sessions would reestablish, and
the other BRAS will setup a new session... No session state between
different devices.

For static pools or even static allocations from RADIUS, you need to send
the allocation from RADIUS for a specific account ID...

Arie

On Wed, Mar 23, 2011 at 4:28 PM, Hitesh Vinzoda <vinzoda.hitesh at gmail.com>wrote:

> Hi Arie,
>
> But the problem is both the LNS would have separate loopback ip addresses
> configured and under virtual-template we will have ip unnumbered loopback
> e.g.
>
> LNS-1 20.20.20.1/24 loopback and Virtual template
> LNS-2 20.20.20.2/24 loopback and Virtual template
>
> Now say a pppoe client has configured default route towards 20.20.20.1
> before failover and after failover it is now connected to LNS-2 whose ip
> address is 20.20.20.2, in this case pppoe client would not be able to route
> out to the internet as the gateway ip address is unreachable.
>
> Another problem is connecting users whom we are going to assing /29 from
> separate pool than the virtual template1 (20.20.20.1 or .2) configured say
> 20.20.50.0/29 etc. than how we can accommodate such users on LNS...
>
> Please provide your inputs
>
> Regards
>
> Hitesh
>
>
> On Wed, Mar 23, 2011 at 6:05 PM, Arie Vayner <ariev at vayner.net> wrote:
>
>> 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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