KB.15.15

Figure 71 Layer 3 forwarding (IP unicast) in DT topology

Distributed trunking restrictions

There are several restrictions with distributed trunking:

Beginning with software version K.15.07, the switch will not allow both Distributed Trunking and

MAC-based mirroring to function simultaneously. The switch will respond as follows:

• If the user attempts to configure both, an error message will appear.

• When a switch is updated from older software to K.15.07, if the older config file has both

Distributed Trunking and MAC-based mirroring, the switch will automatically remove the

MAC-based mirroring lines from the config file, and will give an explanatory error message.

• If a switch is running K.15.07 and an existing config file that has both Distributed Trunking

and MAC-based mirroring is loaded onto the switch, the switch will automatically remove the

MAC-based mirroring lines from the config file, and will give an explanatory error message.

• All DT linked switches must be running the same software version.

• The port trunk links should be configured manually (using manual LACP or manual trunks.)

Dynamic linking across switches is not supported.

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

• A maximum total of 144 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.

168 Port Trunking