Breakout Capability

Due to the rise of flat data center architecture models, breaking out high-speed ports has become a critical requirement. A flat data center architecture is a network and storage design that minimizes or eliminates traditional hierarchical layers. This approach creates a simplified, scalable, and high-performance infrastructure, which leverages breakout capability to optimize network resources.

Breakout capability is the ability to split one high-capacity optical link into multiple lower-capacity links. This is typically done using breakout cables with suitable connectors that divide a single high-speed port into multiple lower-speed connections. Breakout capability is crucial for optimizing available bandwidth and physical infrastructure. For example, it allows a single 100G transceiver port to be split into multiple lower-speed ports.

Breakout relies on the concept of channelization to accomplish the split. Channelization involves splitting a high-speed physical port into multiple lower-speed lanes at the hardware level, using Serializer/Deserializer (SerDes) technology. In other words, breakout is the practical application of channelization, creating multiple lower-speed ports from one high-speed port. Channelization can be configured at the level of an individual port, a block of ports, or a quad of ports. A block of ports is a group of ports that share hardware resources within a Juniper switch or router. For blocks that support breakout capability, SerDes technology enables the flexible allocation and operation of these lanes.

Channelization occurs at the physical layer, splitting a high-speed port into multiple lanes. It differs from Ethernet port channels or link aggregation (LAG). LAG combines multiple physical links into a single logical link at Layer 2 or Layer 3.

You can perform port speed configuration at either the chassis level or the interface level. At the chassis level, you have three main options for port speed configuration:

• Channelize individual port—Configure an individual port to operate at a specific channel speed. You must specify a port number and channel speed.
• Channelize block of ports—Configure a range of ports (a block) to operate at the same channel speed. You must specify the port range and the channel speed.
• Configure speed per quad—Configure port speeds in groups of four ports (quads), not individually. You must specify the speed for the first port in the quad. All four ports operate at the speed that you specified for the first port.

At the interface level, you must configure the speed for individual logical interfaces derived from the physical ports. This helps you in managing breakout interfaces after chassis-level speed settings are applied. For information about interface-level configuration, see Configure Speed at Interfaces Level.

Juniper supports the following breakout speed or mode options for its 100 Gbps ports:

• 4x25G
• 2x50G
• 1x100G (no breakout)

Breakout capability enables a network architect to configure a single port to support standardized 25 Gbps, 50 Gbps, or 100 Gbps data, depending on the network requirement. For more information about the breakout configuration that you can use in your Juniper device, use Port Checker.

100G optical transceivers with QSFP-28 form factor support breakout capability. 100G QSFP28 transceivers use 4x25G lanes (NRZ modulation), making them compatible with 25G optics via breakout cables. Breakout capability enables 100G optical transceivers to provide flexible connectivity with 25G and 50G line cards and platforms deployed in your network.