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In the event of a far-end failure, the device stops receiving frames and, after the specified time interval, assumes that the far-end is
not available. The connecting line protocol is brought down so that upper layer protocols can detect the neighbor unavailability faster.
FEFD State Changes
FEFD has two operational modes, Normal and Aggressive.
When you enable Normal mode on an interface and a far-end failure is detected, no intervention is required to reset the interface to
bring it back to an FEFD operational state. When you enable Aggressive mode on an interface in the same state, manual intervention
is required to reset the interface.
FEFD enabled systems (comprised of one or more interfaces) automatically switchs between four different states: Idle, Unknown, Bi-
directional, and Err-disabled.
1.
An interface on which FEFD is not configured is in Normal mode by default.
2.
After you enable FEFD on an interface, it transitions to the Unknown state and sends an FEFD packet to the remote end of the
link.
3.
When the local interface receives the echoed packet from the remote end, the local interface transitions to the Bi-directional
state.
4.
If the FEFD enabled system is configured to use FEFD in Normal mode and neighboring echoes are not received after three
intervals, (you can set each interval can be set between 3 and 300 seconds) the state changes to unknown.
5.
If the FEFD system has been set to Aggressive mode and neighboring echoes are not received after three intervals, the state
changes to Err-disabled. You must manually reset all interfaces in the Err-disabled state using the
fefd reset
[interface]
command in EXEC privilege mode (it can be done globally or one interface at a time) before the FEFD enabled
system can become operational again.
Table 50. State Change When Configuring FEFD
Local Event
Mode
Local State
Remote State Local Admin
Status
Local Protocol
Status
Remote
Admin Status
Remote
Protocol
Status
Shutdown
Normal
Admin
Shutdown
Unknown
Down
Down
Up
Down
Shutdown
Aggressive
Admin
Shutdown
Err-disabled
Down
Down
Up
Down
FEFD enable
Normal
Bi-directional
Bi-directional
Up
Up
Up
Up
FEFD enable
Aggressive
Bi-directional
Bi-directional
Up
Up
Up
Up
FEFD + FEFD
disable
Normal
Locally
disabled
Unknown
Up
Up
Up
Down
FEFD + FEFD
disable
Aggressive
Locally
disabled
Err-disabled
Up
Down
Up
Down
Link Failure
Normal
Unknown
Unknown
Up
Down
Up
Down
Link Failure
Aggressive
Unknown
Unknown
Up
Down
Up
Down
Important Points to Remember
•
FEFD enabled ports are subject to an 8 to 10 second delay during an RPM failover before becoming operational.
•
You can enable FEFD globally or on a per-interface basis. Interface FEFD configurations override global FEFD configurations.
•
Dell Networking OS supports FEFD on physical Ethernet interfaces only, excluding the management interface.
•
FEFD is not supported on Fibre Channel and copper Ethernet ports.
Configuring FEFD
You can configure FEFD for all interfaces from CONFIGURATION mode, or on individual interfaces from INTERFACE mode.
To enable FEFD globally on all interfaces, use the following command.
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Layer 2
Содержание S4048-ON
Страница 1: ...Dell Configuration Guide for the S4048 ON System 9 9 0 0 ...
Страница 146: ...Figure 14 BFD Three Way Handshake State Changes 146 Bidirectional Forwarding Detection BFD ...
Страница 477: ...Figure 68 Inspecting Configuration of LAG 10 on ALPHA Link Aggregation Control Protocol LACP 477 ...
Страница 480: ...Figure 70 Inspecting a LAG Port on BRAVO Using the show interface Command 480 Link Aggregation Control Protocol LACP ...
Страница 481: ...Figure 71 Inspecting LAG 10 Using the show interfaces port channel Command Link Aggregation Control Protocol LACP 481 ...
Страница 522: ...Figure 87 Configuring Interfaces for MSDP 522 Multicast Source Discovery Protocol MSDP ...
Страница 523: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 523 ...
Страница 524: ...Figure 89 Configuring PIM in Multiple Routing Domains 524 Multicast Source Discovery Protocol MSDP ...
Страница 528: ...Figure 91 MSDP Default Peer Scenario 1 528 Multicast Source Discovery Protocol MSDP ...
Страница 529: ...Figure 92 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 529 ...
Страница 530: ...Figure 93 MSDP Default Peer Scenario 3 530 Multicast Source Discovery Protocol MSDP ...
Страница 633: ...Policy based Routing PBR 633 ...
Страница 777: ...Figure 119 Single and Double Tag TPID Match Service Provider Bridging 777 ...
Страница 778: ...Figure 120 Single and Double Tag First byte TPID Match 778 Service Provider Bridging ...