什么是err-disabled link-flap？cisco的保护技术，如何设置自动恢复？

CISCO厂商的设备为了保证网络的可靠性，启用了相应的保护技术。如：在10秒钟内如果路由器的以太端口反复出现5次up/down的告警，那么CISCO路由器会因检测到端口出现link-flap error错误，而将端口置于err-disable状态。
CISCO7609-1#sh errdisable detect
ErrDisable Reason Detection status
----------------- ----------------
udld Enabled
bpduguard Enabled
security-violatio Enabled
channel-misconfig Enabled
psecure-violation Enabled
mac-limit Enabled
unicast-flood Enabled
vmps Enabled
loopback Enabled
pagp-flap Enabled
dtp-flap Enabled
link-flap Enabled
l2ptguard Enabled
gbic-invalid Enabled
dhcp-rate-limit Enabled
storm-control Enabled
inline-power Enabled
arp-inspection Enabled
packet-buffer Enabled
link-monitor-fail Enabled
oam-remote-failur Enabled
transceiver-incom Enabled
dot1ad-incomp-ety Enabled
dot1ad-incomp-tun Enabled
CISCO7609-1#sh errdisable flap-values
ErrDisable Reason Flaps Time (sec)
----------------- ------ ----------
pagp-flap 3 30
dtp-flap 3 30
link-flap 5 10

CISCO 7609路由器检测到端口出现link-flap error错误后，会将端口置于err-disable状态。不过，CISCO设备针对这个保护技术，也有相应的自动恢复技术。
         当端口因Link-flap error原因而置于err-disable状态后，可以设置一个延时，将端口状态自动恢复正常。
命令为：errdisable recovery cause Link-flap
         默认情况下，自动恢复功能是关闭的，自动恢复延时默认为300秒。只需要开启此功能，并设置合适的自动恢复时间即可。
CISCO7609-1#sh errdisable recovery
ErrDisable Reason Timer Status
----------------- --------------
udld Disabled
bpduguard Disabled
security-violatio Disabled
channel-misconfig Disabled
vmps Disabled
pagp-flap Disabled
dtp-flap Disabled
link-flap Disabled
l2ptguard Disabled
psecure-violation Disabled
gbic-invalid Disabled
dhcp-rate-limit Disabled
mac-limit Disabled
unicast-flood Disabled
storm-control Disabled
arp-inspection Disabled
loopback Disabled
link-monitor-fail Disabled
oam-remote-failur Disabled
dot1ad-incomp-ety Disabled
dot1ad-incomp-tun Disabled
Timer interval: 300 seconds
Interfaces that will be enabled at the next timeout: