Configuration of Dynamic Breakout Ports
Breakout cables are suitable for very short links and offer a cost effective way to connect within racks and across adjacent racks.
Breakout enables a 40 Gigabit (Gb) port to be split into four independent and logical 10Gb ports or a 100Gb port to be split into four independent and logical 25Gb ports.
Before you configure breakout ports, connect a 40Gb port to four 10Gb ports or a 100Gb port to four 25Gb ports with one of the following cables:
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Cisco QSFP-4SFP10G
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Cisco QSFP-4SFP25G
The 40Gb to 10Gb dynamic breakout feature is supported on the access facing ports of the following switches:
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N9K-C9332PQ
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N9K-C93180LC-EX
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N9K-C9336C-FX
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N9K-C9336C-FX2
The 100Gb to 25Gb breakout feature is supported on the access facing ports of the following switches:
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N9K-C93180LC-EX
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N9K-C9336C-FX2
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N9K-C93180YC-FX
Observe the following guidelines and limitations:
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For N9K-C9332PQ switch, you can configure ports 1 to 26 as downlink ports. Of those ports, breakout ports can be configured on port 1 to 12 and 15 to 26. Ports 13 and 14 do not support breakout.
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In general, breakout ports and port profiles (ports changed from uplink to downlink) are not supported on the same port.
However, from Cisco APIC release 3.2, dynamic breakouts (both 100Gb and 40Gb) are supported on profiled QSFP ports on the N9K-C93180YC-FX switch.
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Fast Link Failover policies are not supported on the same port with the dynamic breakout feature.
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Breakout ports cannot be used for Cisco APIC connectivity.
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Breakout subports can be used in the same way other port types in the policy model are used.
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When a port is enabled for dynamic breakout, other policies (expect monitoring policies) on the parent port are no longer valid.
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When a port is enabled for dynamic breakout, other EPG deployments on the parent port are no longer valid.
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A breakout sub-port can not be further broken out using a breakout policy group.
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If the LACP transmit rate on port channels that have breakout sub-ports need to be changed, then all the port channels that include breakout sub-ports need to use the same LACP transmit rate configuration. You can configure an override policy to set the transmit rate as follows:
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Configure/change the default port channel member policy to include Fast Transmit Rate (
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Configure all the PC/vPC interface policy groups to include the above default port channel member policy under the override policy groups (
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