Same Domain ID irf stacks connected via bridge aggregation with Same Domain ID

[HP_Bob]

Helping a client that is having a tough time getting two IRF stacks connected via a 10 gig bridge aggregation..Each irf group is working, one irf group is 4 switches, the other is 7 switches..the concern is both irf domain id's are zero (0). the client has two of the ten gig ports connected and propely aggregated. we can link the two irf groups via a 1 gig link and traffic passes.. if we remove the 1 gig link, traffic will not go thru the 20 gig link.  before opening a case with HP, was trying to find out if anyone knows if there is an issues connecting two IRF domains together with the same Domain ID with the 10 gig links.

[Fredrik Lönnman]

Two different stacks cannot have the same domain ID, things like LACPID is derived from the the domain and can't be the same on two switches. Also it is used as a stack identifier, so if you interconnect them they will probably try to IRF merge since they think they're the same stack.

[manuel.bitzi]

In my opinion IRF Domain ID only cares wenn you use MAD-Detection over LACP. I never changed the domain ID and never had problems with it.

I think it's more a problem with an other part of the configuration.

br

Manuel

[spyd4man]

I agree with the above, I have many IRF stacks which are BriAgg together via LACP, their IRF domain ID's are default at 0.  My understanding is they would cause an issue if you miss-configure your logical IRF ports (i.e you accidentially send IRF traffic over to the other unit).  Or you are using MAD over LACP.

Just to be on the safe side, I now reconfigure all my new IRF stacks to have different domain IDs, as there seems to be no negative aspect to configuring this.

Good luck,

Marc

[Manfred M.]

I definitly don't have any problems with the default IRF domain ID 0 and 10G LACP Bridge Aggregation Groups between 2 IRF STacks. But it is necessary to change it to different numbers if you want to use Multiple Active Detection (MAD) with LACP (which is the best choice in my opinion!).

Good Luck

Manfred

[Peter_Debruyne]

domain ID is ONLY used in the MAD LACP method, it has no relation or impact on any other IRF function or operation. However, with the MAD LACP, the domain IDs should be configured unique per IRF, to avoid "false positive" split brain detection of the IRF.

So the basic link-agg will work fine with the same domain ID. When someone later on decides to enable MAD on the bagg however, you could be in trouble.

This is why it is best practise to assign a unique domain ID at installation time (even when not using MAD LACP), simply to avoid future issues.

A simple rule I recently learned last week is to convert the (loopback) IP of the switch (which is unique by design) from dotted decimal to full decimal (IRF domain ID is 4 bytes) number and use that as the domain ID.

One sheet less to maintain ...