[j-nsp] VC-port over Ethernet

[Nick Kritsky]

Graham,

short answer is - yes, EX-3300 can form VC when connected via 3rd switch.
No special settings are required on the uplink switch. However without
special configuration (q-in-q? jumbo frames?) VC is unstable (see below in
"test results").
here is the test setup.
1. Topology:
ASW13 ---- ASW11 --- ASW14
ASW11 is EX-4200-24T with two 10G interfaces
ASW13, ASW14 are EX-3300 with default configuration

2. Configuration
ASW11:
xe-0/1/0 {
    description sjc-net-asw13:xe-0/1/2;
    unit 0 {
        family ethernet-switching;
    }
}
xe-0/1/2 {
    description sjc-net-asw14:xe-0/1/2;
    unit 0 {
        family ethernet-switching;
    }
}

3. results of tests.
3.1 time T: link up on both 10G ports of ASW11
3.2 time T+2 min: link on one of 10G ports of ASW11 goes down and stays
this way.

Somewhere between 3.1 and 3.2 ASW13 and ASW14 form 2-member VC.
After one of the 10G links goes down, VC obviously becomes crippled.

I also have strong suspicion that connecting vc-port to uplink switch may
result in some nasty 2-minute-long loop that is not blocked by STP. I will
check it tomorrow.

nick



On Wed, Apr 17, 2013 at 5:41 AM, Graham Brown
<juniper-nsp at grahambrown.info>wrote:

> Nick,
>
> Let us know the results of your testing.
>
> However you can disable the default by issuing the below two commands:
> request virtual-chassis vc-port delete pic-slot 1 port 2
> request virtual-chassis vc-port delete pic-slot 1 port 3
>
> HTH,
> Graham
>
>
> On 15 April 2013 23:54, Nick Kritsky <nick.kritsky at gmail.com> wrote:
>
>> Klaus,
>>
>> No, I don't want to form VC between 3300 and 4500.
>>
>> nick
>>
>>
>> On Mon, Apr 15, 2013 at 2:16 PM, Klaus Groeger <klauzi at gmail.com> wrote:
>>
>> > Just one word, to double check if i understand you. You would like to
>> form
>> > a VC between 3300 and 4500?
>> >
>> > That won't work. You can only form VC between 3300 or between 45xxx and
>> > 4200.
>> > Klaus
>> > —
>> > Sent from Mailbox <https://bit.ly/SZvoJe> for iPhone
>>
>> >
>> >
>> > On Mon, Apr 15, 2013 at 9:41 AM, Nick Kritsky <nick.kritsky at gmail.com
>> >wrote:
>> >
>> >> Thanks. Just to clarify - I am actually trying to prevent this from
>> >> happening.
>> >> EX-3300 have ports xe-0/1/2 and xe-0/1/3 put in VC-port mode by
>> default.
>> >> So I wonder if two fresh, brand new EX-3300 can form VC when they are
>> >> plugged into upstream 4550 using vc-ports.
>> >> This can explain some strange behavior i was observing recently, but I
>> >> was too busy fixing it, so I didn't run much tests.
>> >> I plan to setup small lab for that. I will let you know of the outcome.
>> >>
>> >> nick
>> >>
>> >>
>> >> On Sun, Apr 14, 2013 at 4:33 PM, Klaus Groeger <klauzi at gmail.com>
>> wrote:
>> >>
>> >>> Hi
>> >>>
>> >>> I would recommend Q-in-Q on the intermediate switch. I have seen 4550
>> VC
>> >>> spanning over metro erhernet, so this should work for 3300 also.
>> >>>
>> >>> Regards
>> >>>
>> >>> Klauzi
>> >>> —
>> >>> Sent from Mailbox <https://bit.ly/SZvoJe> for iPhone
>>
>> >>>
>> >>>
>> >>> On Sat, Apr 13, 2013 at 9:21 PM, Nick Kritsky <nick.kritsky at gmail.com
>> >wrote:
>> >>>
>> >>>> Dear J-NSP,
>> >>>>
>> >>>> Can anyone confirm/deny if two EX3300 can form virtual-chassis when
>> >>>> their
>> >>>> vc-ports are connected via third switch?
>> >>>>
>> >>>> thanks
>> >>>> nick
>> >>>> _______________________________________________
>> >>>> juniper-nsp mailing list juniper-nsp at puck.nether.net
>> >>>> https://puck.nether.net/mailman/listinfo/juniper-nsp
>> >>>>
>> >>>>
>> >>>
>> >>
>> >
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>
>
>
> --
> Graham Brown
> Twitter - @mountainrescuer <https://twitter.com/#!/mountainrescuer>
> LinkedIn <http://www.linkedin.com/in/grahamcbrown>
>