Solved: Port pair

David Kondicz · ‎03-01-2018

Hi all,

can anyone explain for what is used a Port pair? I found this function in our CISCO DCM GBE Card.

Manual says that port pair means 2 physical interfaces working as one virtual. Ok but how it is workig?

What if i have 2 gbe ports in port pair and i need to handle 1,5 gig traffic? Can i connect both of them into same vlan on the same sw? Or it cases loopback?

The DCM is conected into Catalyst 3560x.

Any idea?

Thank you

Rich Uline · ‎03-01-2018

David,

The datasheet for this device makes it clear that these port pairs are for redundancy and not load balancing. "The two 10 Gigabit Ethernet ports in each layer of the Cisco DCM Media Interface Card can be configured in port pairs where one of the port designated as the backup port would provide redundancy in the case where a loss occurs in the MAIN port." Because we are using these ports for failover and not load balancing, I presume that only one port will ever be in use at any given time. Therefore, I don't believe there is any special configuration required on the switch except to put both ports in the same VLAN. If you observe the switch reporting MAC flapping, then you may need to configure the two switch ports for EtherChannel with mode on.

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Rich Uline · ‎03-01-2018

David,

The datasheet for this device makes it clear that these port pairs are for redundancy and not load balancing. "The two 10 Gigabit Ethernet ports in each layer of the Cisco DCM Media Interface Card can be configured in port pairs where one of the port designated as the backup port would provide redundancy in the case where a loss occurs in the MAIN port." Because we are using these ports for failover and not load balancing, I presume that only one port will ever be in use at any given time. Therefore, I don't believe there is any special configuration required on the switch except to put both ports in the same VLAN. If you observe the switch reporting MAC flapping, then you may need to configure the two switch ports for EtherChannel with mode on.