Broadcom Gigabit Ethernet Teaming Services
NetXtreme
User Guide
Broadcom
®
April 2017 • 2CS57XX-CDUM514-R
Page 121
General Network Considerations
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Teaming with Microsoft NLB/WLBS
Teaming Across Switches
SLB teaming can be configured across switches. The switches, however, must be connected together. Generic
Trunking and Link Aggregation do not work across switches because each of these implementations requires
that all physical adapters in a team share the same Ethernet MAC address. It is important to note that SLB can
only detect the loss of link between the ports in the team and their immediate link partner. SLB has no way of
reacting to other hardware failures in the switches and cannot detect loss of link on other ports.
Switch-Link Fault Tolerance
The diagrams below describe the operation of an SLB team in a switch fault tolerant configuration. We show the
mapping of the ping request and ping replies in an SLB team with two active members. All servers (Blue, Gray
and Red) have a continuous ping to each other.
is a setup without the interconnect cable in place
has the interconnect cable in place, and
is an example of a failover
event with the Interconnect cable in place. These scenarios describe the behavior of teaming across the two
switches and the importance of the interconnect link.
The diagrams show the secondary team member sending the ICMP echo requests (yellow arrows) while the
primary team member receives the respective ICMP echo replies (blue arrows). This illustrates a key
characteristic of the teaming software. The load balancing algorithms do not synchronize how frames are load
balanced when sent or received. In other words, frames for a given conversation can go out and be received on
different interfaces in the team. This is true for all types of teaming supported by Broadcom. Therefore, an
interconnect link must be provided between the switches that connect to ports in the same team.
In the configuration without the interconnect, an ICMP Request from Blue to Gray goes out port 82:83 destined
for Gray port 5E:CA, but the Top Switch has no way to send it there because it cannot go along the 5E:C9 port
on Gray. A similar scenario occurs when Gray attempts to ping Blue. An ICMP Request goes out on 5E:C9
destined for Blue 82:82, but cannot get there. Top Switch does not have an entry for 82:82 in its CAM table
because there is no interconnect between the two switches. Pings, however, flow between Red and Blue and
between Red and Gray.
Furthermore, a failover event would cause additional loss of connectivity. Consider a cable disconnect on the
Top Switch port 4. In this case, Gray would send the ICMP Request to Red 49:C9, but because the Bottom
switch has no entry for 49:C9 in its CAM Table, the frame is flooded to all its ports but cannot find a way to get
to 49:C9.
Summary of Contents for NetXtreme BCM57 Series
Page 1: ...Broadcom NetXtreme BCM57XX User Guide Last revised April 2017 2CS57XX CDUM514 R...
Page 16: ...Functionality and Features NetXtreme User Guide Broadcom April 2017 2CS57XX CDUM514 R Page 16...
Page 169: ...Regulatory Information NetXtreme User Guide Broadcom April 2017 2CS57XX CDUM514 R Page 169...
Page 170: ...Regulatory Information NetXtreme User Guide Broadcom April 2017 2CS57XX CDUM514 R Page 170...
Page 171: ...Regulatory Information NetXtreme User Guide Broadcom April 2017 2CS57XX CDUM514 R Page 171...
