Administrator Guide

Configure MTU Size on an Interface
In Dell EMC Networking OS, Maximum Transmission Unit (MTU) is defined as the entire Ethernet packet (Ethernet header + FCS +
payload).
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
• Enable link bundle monitoring on port channel interfaces.
link-bundle-monitor enable
DellEMC(conf-if-po-10)#link-bundle-monitor enable
• Configure threshold level for link bundle monitoring.
link-bundle-distribution trigger-threshold
DellEMC(conf)#link-bundle-distribution trigger-threshold
• View the link bundle monitoring status.
show link-bundle-distribution
Using Ethernet Pause Frames for Flow Control
Ethernet pause frames and threshold settings are supported on the Dell EMC 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.
Restriction: Ethernet Pause Frame flow control is not supported if PFC is enabled on an interface.
Interfaces
331