HP Procurve IP Routing and Distributed Trunking

[Johan de Greef]

When trying to configure distributed trunking on an HP Procurve 5400 series switch I got an error stating that DT-LACP cannot be enabled as long as IP Routing is enabled. I checked the documentation and found the follow restrictions:

IP routing and distributed trunking are mutually exclusive. Routing restrictions with distributed trunking are switch-wide and do not apply to the DT ports only.

Many websites give this information, but I cannot find the reason why they are mutually exclusive. Can some please enlighten me?

Thanks in advance,
Johan de Greef

[Olaf Borowski · Accepted solution]

Johan,

Just hasn't been implemented yet. This inter-switch link uses a special mechanism to synchnonize MAC address between the two switches. The switch would have to do the same thing for ARP entries etc., which hasn't been done yet. The feature of running routing and DT-LACP simultaniously should be supported some time in the future.

[Antonio Milanese]

@Olaf,

maybe i'm wrong but i doubt that even in its future incarnations dt-lacp will became a fully multi-chassis LACP...HP clearly say that dt-lacp it's only a better way aggregate server traffic at aggeration level.

@Johan

To my understanding as Olaf said it's based on syncing/mirroring LACP aggregator states/keys/pdus, multiplexed traffic plus some other dynamic data-plane learning/forwarding infos:
in short it's a 802.1ax hack where normal LACP data-plane operations are "mirrored" between 2 chassis for end-point servers LACP teams, so it impose some of LACP dictacts like no frame reordering,unbalanced flows ecc.
Put it simply..it's a hostile territory to L3 operations where buffering/queueing/reodering etc are tipical and acceptable events.
Anyway HP correclty target this feature at aggregation layer and not at distribution/core layer and it's my belief that HP will not pursue this strategy now that they have H3C IRF etc

Regards,

Antonio

[ISoliman]

IP Routing and DT are now supported together

[ArvidM]

Hi ISoliman,

Can you specify which firmware currently supports this configuration (IP routing and DT)? I'm making a design for DT with routing on 2 HP5406 Chassis. Is it somewhere written in release notes that it is supported now?

Thanks!

[ISoliman]

Yes it is mentioned in the latest release notes, also Policy Based Routing and BGP are supported, but for PBR you must have all the modules in the chasses V2 modules only or PBR will not be supported.

Please let me know if you need more info aboud DT and routing

[joke3071]

Hi ! Can you specify the release of the firmware? Is K_15_07_0002 fine for routing DT at same time?