Cisco breaks down OLT chassis with new pluggable

  • Cisco launched Routed PON, which collapses the traditional OLT chassis into a small form-factor pluggable

  • Dell'Oro analyst Jeff Heynen said this solution makes it easier for operators by reducing the number of separate platforms they need to manage

  • He also said consolidating OLT and routing functions can provide improved latency

Move over, clunky hardware, Cisco says it's time to make optical line terminals (OLTs) more compact. 

Cisco recently unveiled its new Routed PON solution, which essentially collapses the OLT chassis into a small form-factor pluggable (SFP) that connects an operator’s PON network to Layer 3 routing and services. Layer 3 is also known as the network layer, which is responsible for packet forwarding.

Why get rid of the standalone OLT chassis anyway? Simply put, they’re too big, so they require dedicated space and power, which in turn bumps up costs for telcos, according to Bill Gartner, SVP and GM of Cisco’s Optical Systems and Optics Group.

“Additionally, these chassis are separate from the access router, so they require separate layer management that can be costly,” he wrote in a blog. “Traditional broadband architectures also offer less flexibility because they come as an integrated solution from a single vendor.”

Routed PON gives operators more options while they consolidate their networks. Dell’Oro analyst Jeff Heynen said Cisco’s solution lets providers use “any number of optical ports available on their aggregation routers into OLTs through an SFP and a container-based PON controller and manager.”

In English, please?

“Essentially, that allows providers to consolidate their access and aggregation networks, thereby reducing the number of separate platforms they need to manage because you are eliminating the need for a separate OLT chassis,” Heynen explained.

It comes back to convergence

He added Routed PON allows operators to converge their PON service and Ethernet services “onto a single transport network.”

Convergence is kind of a big buzzword in broadband industry. Operators are trying to figure out how to bring together various fixed and mobile networks, so customers don’t notice when they switch between a wired connection and Wi-Fi, Bluetooth, etc.

Cisco, along with a handful of vendors such as Ciena, Nokia, Mavenir and Intel, joined CableLabs’ Convergence Council in 2021 to determine which parts of the network need to be converged first.

Heynen explained that over the years, routers have integrated different network functions because they are in access, aggregation and metro edge networks. The Broadband Network Gateway (BNG) is a prime example.

Just like with the OLT chassis, Cisco’s Routed PON enables routers to collapse both the PON and BNG/vBNG functions into a single platform, he said.

“As PON moves from being primarily a residential broadband technology to enterprise, leased line and mobile backhaul technologies, consolidating the OLT and routing functions could provide benefits in terms of improved latency,” Heynen concluded.

It's worth noting that Cisco isn't the only one putting out pluggable optics - Infinera and Ciena have had similar products on the market for years now.

Editor's Note: This story was updated on 3/25/2024 to mention Ciena and Infinera also have pluggable optics on the market.