Network reality, from packets upward.
Underlay treats networks as systems that have to be understood from the packet level up. Its recent conversations move between gRPC, gNMI, operational state data, SD-WAN application performance, and the practical habits people use when troubleshooting.
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Underlay is a technical show about digital infrastructure, with networking as its center of gravity. Its recent episode excerpts point to a catalog concerned with packet-level truth, automation, telemetry, SD-WAN, WAN optimization, and the messy work of keeping production systems understandable. The show does not treat infrastructure as an abstract layer. It keeps coming back to what people can see, measure, configure, and troubleshoot. Packet captures become a way to settle uncertainty. Operational state data becomes a way to ask whether the network is actually behaving as expected. gRPC and gNMI are discussed alongside NetConf, RESTConf, YANG, and telemetry as part of a wider search for better network management patterns. SD-WAN is handled through performance limits, path selection, latency, application sensitivity, and the tradeoffs that appear when private circuits cannot simply be removed. The register is conversational, but the subject matter is precise. Guests and speakers explain their background, compare tools, and work through practical examples rather than staying at the level of slogans. Some episodes come through Network Collective formats, including community roundtables and Network to Code conversations. Others carry the Riverbed Technical Podcast frame, with packet analysis and application acceleration front and center. The show also has an unusually self-aware thread about format. In “New Year New Us?”, the speakers describe a history of unscripted conversations with smart people and consider more edited, narrative approaches built from multiple perspectives. That matters because it matches the material. Networking is full of competing claims, vendor language, and inherited habits, and Underlay is strongest when it slows those down into concrete operational questions. What evidence proves the fault? Which protocol model fits the task? Where does automation help, and where does it merely rename old work? The result is a show for people who want infrastructure explained by people close to the machinery. It is not polished futurism. It is working technical conversation, grounded in packets, state, tools, and the humans responsible for making them line up.
Made for: Suits a listener who wants serious networking discussion around automation, visibility, protocols, and troubleshooting. It is especially useful for someone comfortable with terms like gRPC, gNMI, YANG, SD-WAN, and packet capture.
What sets it apart: Underlay stands out by pairing low-level evidence, especially packets and operational state, with candid discussion of how people actually reason through infrastructure change. The excerpts also show a willingness to rethink the show’s own format instead of treating technical conversation as fixed.
Exploring the intersection of digital infrastructure and the humans who depend on it. https://underlay.show
A slow office phone meets packet captures, and your inner network detective gets a proper case.
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Short reviews from the PlayNext desk, based on the episodes we processed.
A candid reset on machine learning, podcast form, and Network Collective's next shape.
Network Collective returns as a reunion with a reset tucked inside it, as Jordan and Tony pick up after a long break and talk through what the project could become next.
A focused packet-level troubleshooting session, anchored by a memorable delayed dial tone case.
Packet captures take center stage as Phil Gervasi, Brandon Carroll, and Kerry Rogers work through what network visibility really looks like when the evidence is moving across the wire.
A practical gNMI overview that ties configuration, operational state, and telemetry to gRPC-based network management.
gNMI gets a clear, practical introduction here, picking up from an earlier gRPC discussion and moving into device configuration, operational state, and telemetry subscriptions.
A grounded SD-WAN review of where overlays help and where latency and sensitive applications still set the terms.
SD-WAN often gets sold as the clean break from MPLS, but this episode keeps that promise grounded in how networks actually behave. Phil Gervasi and Brandon Carroll speak with John Pittle, Riverbed's Professional Services Chief Technology Officer, about WANOP and SD-WAN, with the…
A practical gRPC discussion that links YANG-driven network automation with broader service design.
Jordan Martin's conversation with Nick Russo and Darren O'Connor gives network programmability a practical frame, using gRPC as a tool that belongs in the automation toolbox rather than as a cure-all.
IPv6 operations, from RFCs to real networks.
Enterprise tech made operationally clear.
Infrastructure talk across the Packet Pushers network.
Packet-level detail across modern infrastructure.
Real-world context for network design.
Patient tech fixes, one setting at a time.
["Jordan and Tony reopen Network Collective after a long break, and Jordan says the episode is meant to explain where the show is headed next.", "Tony says he has been teaching himself Python, Jupyter notebooks, machine learning, and packet analysis, while Jordan describes a two-month RV road trip and a much busier job.", "They say the summer 2021 pace became unsustainable because podcast episodes, partner episodes, and a weekly livestream took too much back-end work for two full-time jobs.", "The reset includes a new name, Underlay, a broader focus on digital infrastructure and security topics like SASE, and the end of the paid supporter-community perk."]
["Kerry Rogers argues that packet captures are the fastest way to diagnose network problems when SNMP, flow logs, and summaries only show the cliff notes.", "He recounts a transatlantic throughput issue where east-to-UK traffic looked fine, the reverse direction stalled, and TCP retransmissions never recovered because a Cisco firewall left SACK blocks invalid after sequence-number translation.", "Phil Gervasi and Brandon Carroll push on the limits of Wireshark, dumpcap, TShark, and trace Wrangler, and Kerry keeps returning to one workflow: narrow the scope, capture the three-way handshake, then open the PCAP.", "The episode stays practical, with examples from Riverbed support, a school-district Firepower case, and an Alaska Steelhead deployment where QoS markings changed the troubleshooting outcome."]
["Network Collective Community Roundtable returns to GNMI after the earlier gRPC episode with Nick Russo and Darren O'Connor.", "Nick Russo defines GNMI as GRPC Network Management Interface and walks through four RPCs: capabilities, get, set, and subscribe.", "Roman Dodin says OpenConfig publishes the spec on GitHub rather than as an IETF RFC, while vendors like Cisco, Juniper, and Nokia still vary in implementation details.", "The discussion lands on telemetry subscriptions, YANG XPath paths, and practical learning aids such as Bruno's IOS XR article, GNMIC, and Wireshark packet captures."]
["Riverbed Technical Podcast hosts Phil Gervasi and Brandon Carroll interview John Piddle, Riverbed's Professional Services CTO, about application acceleration and SD-WAN.", "Piddle says SD-WAN helps with branch onboarding, path selection, and centralized policy rollout, but it is not a \"magic wand\" that fixes every network problem.", "The technical core is latency: Piddle defines it as propagation delay and uses the equation \"latency times turns equals pain\" to show why high-turn applications slow down.", "The conclusion is that SD-WAN and WAN optimization are complementary, because SD-WAN steers traffic while application acceleration reduces turns, response time, and pain for SaaS and SMB-heavy workloads."]
Jordan Martin opens the Network Collective Community Roundtable by asking what gRPC is and why it belongs in network automation.
Justin Pietsch frames historical operational data as a “network flight recorder” that lets operators replay network events.
Underlay's Brandon Carroll, Phil Gervassi, and Vince Burke frame the 80/20 rule around SaaS and infrastructure as a service.
An interview with networking expert Ivan discussing the evolution of SDN and network automation over the past decade.
An interview with a network automation evangelist discussing the Init6 podcast and the evolution of networking certifications.
Interview with Stuart Clark about his career transition from barber to technical leader at Cisco, focusing on network automation.
An interview with Tony Nealon, creator of NetPalm, discussing the open-source network automation tool and its use cases.
An interview with Jason Nettleman about his journey into networking and founding Network to Code, focusing on network automation.
Hosts discuss lessons learned from upgrading network switches for clients, including on-site and remote work.