ZNDP 005 – Carrier Supporting Carrier (CSC) with Nick Russo

Welcome back Nerds, Geeks, and Ziglets for another episode of the Zigbits Network Design Podcast (ZNDP), where Zigabytes are faster than Gigabytes. As always our goal is to provide you with real world context around technology. I’m Michael Zsiga, also known as Zig, and I am your host. We have an awesome show for you today, fully packed with a ton of technology, business requirements, constraints and drivers. I’m extremely excited for today’s episode as we have our first Guest Expert joining us, my good friend Nick Russo!  Today’s topic is Carrier Supporting Carrier (CSC)!

1. High level summary of technology solution

Consuming Carrier Supporting Carrier (CSC) in the US Federal space as the core carrier solves a number of business and technical use cases for us. Interesting point is the concept of “Managed Services” which is like a “Managed PE” in a sense.

Before we get a head of ourselves here, what is CSC?

Carrier Supporting Carrier (CSC) is effectively an outsourced core transport technique. Pretend you don’t have an MPLS core but want MPLS Point of Presences (POPs) scattered around the network to provide multi-tenant network services to customers. Using Carrier Supporting Carrier (CSC) is a natural solution, especially when scale and media independence are business drivers or business constraints.

2. High Level Business Requirements & Constraints (00:03:45)

  • Multi-tenancy over WAN
    • Customer security perspective
    • Overlapping IP addresses perspective
  • Unicast and High Bandwidth Multicast flows
  • Rapid Provisioning ( < 10 Minutes)
  • Vendor Agnostic
  • Media independence:
    • High number of International connectivity locations
  • Scale for small Point of Presences (POPs), but not large ones
  • Impossibly small capital expenditure (CAPEX) budget
  • Small operational expenditure (OPEX) budget:
    • Only ~3 total senior engineers to plan, design, and implement solution.
    • An additional ~3 junior engineers to Operate and Maintain solution (OAM)
  • Minimal changes to existing devices, like PE routers for example
  • Don’t change what we don’t have to change in the brownfield environment

3. Full list of technical solutions that were compared (00:13:51)

Transport topology:

1. IGP+LDP CSC-CE to CSC-PE
2. eBGP+Label CSC-CE to CSC-PE with IGP/eBGP redistribution
3. eBGP+Label CSC-CE to CSC-PE with iBGP+Label to the PE

VPN topology:

1. Full mesh between A-A and B-B routers in 7 large POPs; Regionalize small POPs into two closest large POP Route Reflectors
2. Two tier hierarchical Route Reflector design with dedicated top-tier Route Reflectors placed in two large POPs
3. Two tier hierarchical route reflector design by using “new” dedicated routers as second tier route reflectors

4. Additional Services (00:38:55)

Nick goes into some serious technical detail into the additional Services and Design elements that this CSC deployment is running, to include Multicast (mVPN), IPv4 / IPv6 services, Route Target & Route Distinguisher, and the overarching Security Architecture. We then discuss some words of advice for the community in regards to CSC.

Guest: Nicholas (Nick) Russo


How to stay engaged with Nick:


Hosted By: Michael “Zig” Zsiga

Hey Ziglets that’s going to close out this episode of the Zigbits Network Design Podcast (ZNDP) on Carrier Supporting Carrier (CSC) with Nicholas (Nick) Russo, Thanks for listening! Be sure to visit zigbits.tech to join the conversation and access the show notes. If you liked today’s episode, if it inspired you, resonated something within you, or provided a level of real world context let us know. You can find us on Twitter and LinkedIn by searching for Zigbits. You can also send us an email to Feedback@zigbits.tech.

Don’t forget to join us in two weeks for another episode, where we will continue to provide real world context around technology.

Michael “Zig” Zsiga II, CCDE™ 2016::32, CCIE™ #44883 has been in the networking industry a little over 15 years. He is currently a Lead Technical Architect at ePlus in the New England region of the United States. Zig holds an active CCDE and two CCIE certifications, one in Routing and Switching and the second in Service Provider. Zig also holds a Bachelor’s of Science in Computer Science from Park University. Zig is a father, a husband, a United States Marine, a gamer, a nerd, a geek and a big soccer fan. Zig loves all technology and can usually be found in the lab learning and teaching others. Zig is a co-organizer of The Boston Network Operators Group (www.bosnog.org), runs multiple CCIE Study groups, and is a newly published author. Zig lives in New Hampshire, USA with his wife, Julie and their son Gunnar.