PT CPC5565, Руководство пользователя, Страница: 48 / 118

Chapter 3: Getting Started
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Network Architecture Considerations
Typical configurations that utilize the CPC5565 include two CPSB switch fabrics in the chassis.
The CPSB-A port of the CPC5565 connects to Fabric-A and the CPSB-B port of the CPC5565
connects to Fabric-B. The switch fabrics are often connected via an Inter-Switch Link (ISL).
See
Figure 3-10 .
Figure 3-10: Inter-Switch Link Connection
As can be seen from Figure 3-10 , several potential sources of network loops exist. In order to
avoid these, a combination of VLAN configuration and Spanning Tree is required.
The CPC5565 does not participate in the Spanning Tree protocol, but most CPSB fabric
switches, including the PT-CPC6620, do. In order to allow STP devices to detect and block
loops, the BCM5389 switch on the CPC5565 is configured to pass STP Bridge Protocol Data
Units (BPDUs) between ports that are in common VLANs. Since the default VLAN
memberships place the fabric ports in separate VLANs, the default state of the switch is to
block Spanning Tree PDUs from flowing between these ports, but the separate VLANs prevent
broadcast storms.
Avoiding Loops
The primary methods to avoid network loops are:
• Create separate switching domains through wiring and/or VLAN management
• Use Spanning Tree
Separate Switching Domains
One solution to avoiding loops is to break the inter-switch link between the fabrics and create
separate traffic domains using VLAN management. In order to provide redundancy with this
configuration, the CPC5565 application software typically includes a high-availability protocol
such as:
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10GBASE-CX4 10GBASE-CX4 CONSOLE MGMT 10/100
SPD SPD LINK
CPC6620
LNK/ACT/SPD
10G 25
1
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26 CompactPCI
R CPC6620
FABRIC-A
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10GBASE-CX4 10GBASE-CX4
CONSOLE MGMT 10/100
SPD SPD LINK
CPC6620
LNK/ACT/SPD
10G
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CompactPCI
R CPC6620
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10GBASE-CX4 10GBASE-CX4 CONSOLE MGMT 10/100
SPD SPD LINK
CPC6620
LNK/ACT/SPD
10G 25
1
2
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4
56
7
8
91
0
1
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1 2
13
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PWR
FL
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26 CompactPCI
R CPC6620
FABRIC-B
P M C
CPC5565
BCM5389 SWITCH
PMC CPU
P M C
CPC5565
BCM5389 SWITCH
PMC CPU
ISL