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Uplink Failure Detection (UFD)
Uplink failure detection (UFD) provides detection of the loss of upstream connectivity and, if used with network interface controller
(NIC) teaming, automatic recovery from a failed link.
Feature Description
A switch provides upstream connectivity for devices, such as servers. If a switch loses its upstream connectivity, downstream
devices also lose their connectivity. However, the devices do not receive a direct indication that upstream connectivity is lost
because connectivity to the switch is still operational.
UFD allows a switch to associate downstream interfaces with upstream interfaces. When upstream connectivity fails, the switch
disables the downstream links. Failures on the downstream links allow downstream devices to recognize the loss of upstream
connectivity.
For example, as shown in the following illustration, Switches S1 and S2 both have upstream connectivity to Router R1 and
downstream connectivity to the server. UFD operation is shown in Steps A through C:
•
In Step A, the server configuration uses the connection to S1 as the primary path. Network traffic flows from the server to S1
and then upstream to R1.
•
In Step B, the upstream link between S1 and R1 fails. The server continues to use the link to S1 for its network traffic, but the
traffic is not successfully switched through S1 because the upstream link is down.
•
In Step C, UFD on S1 disables the link to the server. The server then stops using the link to S1 and switches to using its link to S2
to send traffic upstream to R1.
Uplink Failure Detection (UFD)
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Summary of Contents for S4048-ON
Page 1: ...Dell Configuration Guide for the S4048 ON System 9 9 0 0 ...
Page 146: ...Figure 14 BFD Three Way Handshake State Changes 146 Bidirectional Forwarding Detection BFD ...
Page 522: ...Figure 87 Configuring Interfaces for MSDP 522 Multicast Source Discovery Protocol MSDP ...
Page 523: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 523 ...
Page 528: ...Figure 91 MSDP Default Peer Scenario 1 528 Multicast Source Discovery Protocol MSDP ...
Page 529: ...Figure 92 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 529 ...
Page 530: ...Figure 93 MSDP Default Peer Scenario 3 530 Multicast Source Discovery Protocol MSDP ...
Page 633: ...Policy based Routing PBR 633 ...
Page 777: ...Figure 119 Single and Double Tag TPID Match Service Provider Bridging 777 ...
Page 778: ...Figure 120 Single and Double Tag First byte TPID Match 778 Service Provider Bridging ...