[c-nsp] Add 2nd Trunk

Tom Storey tom at snnap.net
Sat Jun 8 07:02:50 EDT 2013


There should be no loops as the two router ports are routed, not switched.

Configure the second trunk on the switch, and plug the cable in to the
second router port, make sure its up/up on both ends and configure a test
service on it to be 100% sure traffic is flowing over it.

Then in a text editor stage the configuration snippets you need to "no" the
interface off the old interface, and re-configure it on the new one. Then
copy/paste one by one, making sure after each one that you can ping the
remote device.

The move should be quick, MAC and ARP tables should update fairly quickly,
within a couple of seconds if there is traffic. Use a ping to generate some
traffic if need be.

Do it early in the morning to minimise any impact (look at your traffic
graphs to work out when the quietest time is), but it should already be as
minimal as possible anyway.


On 8 June 2013 10:53, Ahmed Hilmy <hilmy.aa at gmail.com> wrote:

> Thanks Tom for your kind email.
> I got your points.
> our customers will never accept any interruption !!!
> i can move some VLANs from 1st trunk to 2nd one, in this case should i
> care about loop ?  i think it will not happen , each trunk will carry
> different VLANs and at swtich side configure 2nd trunk ?
>
>
> On Sat, Jun 8, 2013 at 3:40 AM, Tom Storey <tom at snnap.net> wrote:
>
>> Depending on the hashing algoritm, it is still possible for one link to
>> run hotter than the other in a bundle.
>>
>> Just like it is possible for the right mix of customers to run one link
>> hotter than the other.
>>
>> Using a second trunk means that most customers will not experience any
>> interruption, only the customers whos configuration is moved from one GigE
>> to the other will experience a brief interruption. Using a bundle you would
>> need to interrupt all customers to implement it, however, it also provides
>> a level of redundancy if one GigE fails for some reason.
>>
>> A bundle also allows for capacity increases to be implemented quite
>> easily in the future too.
>>
>> All valid solutions with pro's and con's. :-)
>>
>>
>> On 7 June 2013 21:35, Ahmed Hilmy <hilmy.aa at gmail.com> wrote:
>>
>>> Hello Friends,
>>>
>>> I have a Cisco SW ( 3560 ) with one Trunk link to my router ( 7606 ),
>>> Trunk
>>> link is fully utilized so i need to add 2nd Trunk.
>>> Shall all move some customers from old trunk to 2nd one and create a new
>>> subterface for them ?
>>>
>>> I am think if i can create bundle and add subinterfaces under this
>>> bundle ?
>>>
>>> Add two GE ports to be memeber of this bundle ?
>>>
>>> Please advice
>>>
>>> Regards,
>>> Ahmed
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>>
>>
>


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