[j-nsp] EX_4500 Dot1q-LAG and MSTP Query !

[vaibhava varma]

Hi Chuck

Thanks for your help and answers.

Yes I had two different questions:

1. Do I need to create L2 VLANs for L3-dot1q interfaces in
Junos-EX4500..I think answer is know
2. For MSTP All the L2 VLANs need not be created on every switch but
only the instance-vlan mapping has to match.

Regards
Varma

On Sat, Jan 28, 2012 at 6:28 AM, Chuck Anderson <cra at wpi.edu> wrote:
> Correcting myself, now that I look at your config more closely, it is
> not a L2 VLAN but rather a L3 VLAN config.  I don't think you can run
> MSTP with that.  For a L2 MSTP config you would need something like:
>
> set interfaces ae1.0 family ethernet-switching vlan members 3042
> set interfaces vlan.3042 family inet address 172.16.0.34/30
> set vlans FOO vlan-id 3042
> set vlans FOO l3-interface vlan.3042
> set protocols mstp interface ae1.0
>
> and then assign all vlans to msti like this across all switches in the
> MSTP Region:
>
> set protocols mstp msti 1 vlan x
> set protocols mstp msti 1 vlan y
> set protocols mstp msti 1 vlan 3042
> set protocols mstp msti 2 ...
> set protocols mstp msti 2 ...
> set protocols mstp msti 3 ...
> set protocols mstp msti 3 ...
>
> But I haven't tried a L3 config like yours, so it may work with
> MSTP...
>
> On Fri, Jan 27, 2012 at 09:26:27AM -0500, Chuck Anderson wrote:
>> On Fri, Jan 27, 2012 at 12:25:18PM +0530, vaibhava varma wrote:
>> > In the Juniper EX-4500 series switch if we are using a LAG say ae1 and
>> > want to run dot1q peering on it with MX-240 upstreams is it necessary
>> > to create the L2 VLAN also in the Switch e.g
>> >
>> > set interfaces ae1 vlan-tagging
>> > set interfaces ae1 description Interconnection-to-bbsw01-ae1
>> > set interfaces ae1.3042 vlan-id 3042
>> > set interfaces ae1.3042 description Interconnect_Control_bbsw01
>> > set interfaces ae1.3042 family inet address 172.16.0.34/30
>> >
>> > Does the VLAN 3042 needs to be added separately in the VLAN Database.
>> > My understanding was that is not needed .
>>
>> Incorrect, you need to define it in the switch simply like this:
>>
>> set vlans FOO vlan-id 3042
>>
>> > ALso regarding the MSTP configuration is it mandatory to create all
>> > the L2 VLANs in the VLAN Database for which we creating
>> > instance-to-vlan mapping.
>>
>> No.  You DO have to specify the entire list of VLAN IDs you want to
>> associate with each MSTI (this is a requirement of any MSTP switch),
>> but you do NOT need to create those VLANs under "edit vlans" unless
>> you are going to use them to forward traffic on some interfaces on
>> that switch.
>>
>> > In a bigger network with lots of switches why do we need to create
>> > those L2 VLANS on a Switch for which its not catering any traffic.
>>
>> You don't.  You just have to map them to each MSTI so that the MSTP
>> Configuration Digest is calculated identically on all switches in the
>> entire MSTP Region.  If you don't have a matching digest
>> (i.e. matching VLAN <--> MSTI associations for every MSTI) then each
>> switch with a different digest will create a boundary and split the
>> network into multiple separate MSTP Regions.  You can't load-balance
>> VLANs between multiple links across such a boundary.
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-- 
Regards
Vaibhava Varma