Users Guide

12–Marvell Teaming Services
Application Considerations
Doc No. BC0054508-00 Rev. R
January 21, 2021 Page 187 Copyright © 2021 Marvell
The designated path is determined by two factors:
 Client-Server ARP cache points to the backup server MAC address. This
address is determined by the Marvell intermediate driver inbound load
balancing algorithm.
 The physical adapter interface on Client-Server Red transmits the data. The
Marvell intermediate driver outbound load-balancing algorithm determines
the data (see “Outbound Traffic Flow” on page 160 and “Inbound Traffic
Flow (SLB Only)” on page 160.
The teamed interface on the backup server transmits a gratuitous address
resolution protocol (G-ARP) to Client-Server Red, which in turn causes the
client-server ARP cache to get updated with the Backup Server MAC address.
The load balancing mechanism within the teamed interface determines the MAC
address embedded in the G-ARP. The selected MAC address is essentially the
destination for data transfer from the client server.
On Client-Server Red, the SLB teaming algorithm will determine which of the two
adapter interfaces is used to transmit data. In this example, data from Client
Server Red is received on the backup server Adapter A interface. To demonstrate
the SLB mechanisms when additional load is placed on the teamed interface,
consider the scenario when the backup server initiates a second backup
operation: one to Client-Server Red, and one to Client-Server Blue. The route that
Client-Server Blue uses to send data to the backup server is dependent on its
ARP cache, which points to the backup server MAC address. Because Adapter A
of the backup server is already under load from its backup operation with
Client-Sever Red, the Backup Server invokes its SLB algorithm to inform
Client-Server Blue (through an G-ARP) to update its ARP cache to reflect the
backup server Adapter B MAC address. When Client-Server Blue needs to
transmit data, it uses either one of its adapter interfaces, which is determined by
its own SLB algorithm. What is important is that data from Client-Server Blue is
received by the Backup Server Adapter B interface, and not by its Adapter A
interface. This action is important because, with both backup streams running
simultaneously, the backup server must load balance data streams from different
clients. With both backup streams running, each adapter interface on the backup
server is processing an equal load, thus load-balancing data across both adapter
interfaces.
The same algorithm applies if a third and fourth backup operation is initiated from
the backup server. The teamed interface on the backup server transmits a unicast
G-ARP to backup clients to inform them to update their ARP cache. Each client
then transmits backup data along a route to the target MAC address on the
backup server.