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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.
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
]
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.
Changes in the flow-control values may not be reflected automatically in the
show interface
output. To display the change,
apply the new flow-control setting, shutdown the interface using the
shutdown
command, enable the interface using the
no
shutdown
command, and use the
show interface
command to verify the changes.
Enabling Pause Frames
Enable Ethernet pause frames flow control on all ports on a chassis or a line card. If not, the system may exhibit unpredictable
behavior.
NOTE: Changes in the flow-control values may not be reflected automatically in the
show interface
output. As a
workaround, apply the new settings, execute
shut
then
no shut
on the interface, and then check the running-config
of the port.
NOTE: If you disable
rx flow control
, Dell Networking recommends rebooting the system.
The flow control sender and receiver must be on the same port-pipe. Flow control is not supported across different port-pipes.
To enable pause frames, use the following command.
•
Control how the system responds to and generates 802.3x pause frames on the Ethernet ports.
INTERFACE mode
Interfaces
393
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 ...