Administrator Guide

Port Pipes
A port pipe is a Dell Networking-specific term for the hardware packet-processing elements that handle network traffic to and
from a set of front-end I/O ports. The physical, front-end I/O ports are referred to as a port set. The system has 10 switch
cards and each card has only one port pipe and 48 ports in each.
● For ports connected through the port extender, you can have a maximum of 4 sessions system.
● For ports directly attached to the chassis you can have a maximum of 4 sessions per port pipe.
Refer to Port Numbering Convention for the exact port location on switch line cards.
Configure MTU Size on an Interface
Maximum Transmission Unit (MTU) is defined as the entire Ethernet packet (Ethernet header + FCS + payload).
The link MTU is the frame size of a packet, and the IP MTU size is used for IP fragmentation. If the system determines that the
IP packet must be fragmented as it leaves the interface, the system divides the packet into fragments no bigger than the size
set in the ip mtu command.
NOTE: Because different networking vendors define MTU differently, check their documentation when planning MTU sizes
across a network.
The following table lists the range for each transmission media.
Transmission
Media
MTU Range (in bytes)
Ethernet
The MTU range is from 594 to 9216, with a default of 1554.
The IP MTU automatically configures.
Using Ethernet Pause Frames for Flow Control
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.
Control how the system responds to and generates 802.3x pause frames on Ethernet interfaces. The default is rx off tx off.
INTERFACE mode. flowcontrol rx [off | on] tx [off | on] monitor session-ID
Where:
rx on: Processes the received flow control frames on this port.
rx off: Ignores the received flow control frames on this port.
tx on: Sends control frames from this port to the connected device when a higher rate of traffic is received.
tx off: Flow control frames are not sent from this port to the connected device when a higher rate of traffic is received.
monitor session-ID: Enables mirror flow control frames on this port.
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Interfaces