Distributed Trunking Cheat Sheet

By esupport posted Sep 30, 2020 10:36 PM


Is there a Distributed Trunking Cheat Sheet?


Distributed Trunking Cheat Sheet

You must configure the ISC ports before you can configure the trunks for distributed trunking.

To configure an ISC port, enter this command:

Syntax: switch-interconnect <port-num | trk1...trkN>

                switch-interconnect  b21

To configure distributed trunking on the switch, enter this command:

Syntax: trunk <port-list> <trk1 | trk2 ... trkN> [trunk | lacp | dt-lacp] no trunk <port-list>      trunk b11 trk1 dt-lacp

Configures distributed trunking on a switch. Use the dt-lacp option. The trunk groups must be identical in both switches, for example, if Switch Local is configured with trk1 and uses the dt-lacp option, Switch Remote must be configured with trk1 and use the dt-lacp option also in order to form a Distributed Trunk.


Example of Configuring Distributed Trunking:

ProCurve Switch Local(config)# switch-interconnect a7

ProCurve Switch Remote(config)# switch-interconnect b9

ProCurve Switch Local(config)# trunk a9 trk10 dt-lacp

ProCurve Switch Remote(config)# trunk a9 trk10 dt-lacp


To display information about the distributed trunks, enter the show lacp distributed command.

Syntax: show lacp [distributed]


Distributed Trunking Restrictions

There are several restrictions with distributed trunking.

■ The port trunk links should be configured manually (manual LACP). Dynamic linking across switches is not supported.

■ Only servers are supported as Distributed Trunking Devices (DTDs).

■ A distributed trunk can span a maximum of two switches.

■ A maximum total of 60 servers can be connected to two DT switches. Each server can have up to four physical links aggregated in a single switch, meaning that there can be a maximum of eight ports (four aggregated links for each DT switch) included in a DT trunk.

■ Only one ISC link is supported per switch with a maximum of 60 DT trunks supported on the switch. The ISC link can be configured as a manual LACP trunk, non-protocol trunk, or as an individual link. Dynamic LACP trunks are not supported as ISCs.

■ An ISC port becomes a member of all VLANs that are configured on the switch. When a new VLAN is configured, the ISC ports become members of that VLAN.

■ Port trunk links can be done only on a maximum of two switches that are connected to a specific server.

■ Any VLAN that is in a distributed trunk must be configured on both switches. By default, the distributed trunk belongs to the default VLAN.

■ There can be eight links in a distributed trunk grouped across two switches, with a limit of four links per distributed trunking switch.

■ The limit of 60 manual trunks per switch includes distributed trunking manual trunks as well.

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.

■ Meshing and DT switches are mutually exclusive.

■ ARP protection is not supported on the distributed trunks.

■ STP is disabled on DT ports.

■ QinQ in mixed VLAN mode and distributed trunking are mutually exclusive.

■ SVLANs in mixed mode are not supported on DT or ISC links.

DHCP snooping and IGMP snooping are not supported on DT links.




Feb 25, 2021 03:21 PM

This document is quite old I guess.
I remember that IP routing and connecting switches instead of only servers to distributed trunks was supported in early KX.15. versions.

Oct 01, 2020 10:59 AM

To be clear, does the restriction "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." mean that VRRP can't be implemented on a pair of already "DT interconnected" chassis? Thanks.