Dell S4820T, Configuration Manual

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The following table lists the range for each transmission media.
Transmission
Media MTU Range (in bytes)
Ethernet
594-12000 = link MTU
576-9234 = IP MTU
Link Bundle Monitoring
Monitoring linked LAG bundles allows traffic distribution amounts in a link to be monitored for unfair
distribution at any given time. A threshold of 60% is defined as an acceptable amount of traffic on a
member link. Links are monitored in 15-second intervals for three consecutive instances. Any deviation
within that time sends Syslog and an alarm event generates. When the deviation clears, another Syslog
sends and a clear alarm event generates.
The link bundle utilization is calculated as the total bandwidth of all links divided by the total bytes-per-
second of all links. If you enable monitoring, the utilization calculation is performed when the utilization
of the link-bundle (not a link within a bundle) exceeds 60%.
To enable and view link bundle monitoring, use the following commands.
• Enable link bundle monitoring.
ecmp-group
• View all LAG link bundles being monitored.
show running-config ecmp-group
Using Ethernet Pause Frames for Flow Control
Ethernet pause frames and threshold settings are supported on the Dell Networking OS.
Ethernet Pause Frames allow for a temporary stop in data transmission. A situation may arise where a
sending device may transmit data faster than a destination device can accept it. The destination sends a
PAUSE frame back to the source, stopping the sender’s transmission for a period of time.
An Ethernet interface starts to send pause frames to a sending device when the transmission rate of
ingress traffic exceeds the egress port speed. The interface stops sending pause frames when the ingress
rate falls to less than or equal to egress port speed.
The globally assigned 48-bit Multicast address 01-80-C2-00-00-01 is used to send and receive pause
frames. To allow full-duplex flow control, stations implementing the pause operation instruct the MAC to
enable reception of frames with destination address equal to this multicast address.
The PAUSE frame is defined by IEEE 802.3x and uses MAC Control frames to carry the PAUSE commands.
Ethernet pause frames are supported on full duplex only.
If a port is over-subscribed, Ethernet Pause Frame flow control does not ensure no-loss behavior.
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Interfaces