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What to keep in mind before migrating to ALL-IP?

In Germany, PSTN carriers announced long time ago (!) to decommission their legacy PSTN access links (analog/ISDN …). Today, mid 2018, we are still not yet on ALL-IP everywhere. Migrations towards ALL-IP (SIP) are still in progress.

The unified communication projects I carried out the last years almost always included advisory services to design and deliver a future proof ALL-IP concept for different voice (PBX) infrastructures (Alcatel-Lucent Enterprise OmniPCX, Cisco Unified Communications Manager, Skype for Business (onprem/online), Teams …). It’s daily business to think and plan for ALL-IP. Designing and planning solution and services for communication always includes at least the discussion of PSTN trunk design options to a certain level depending on the consulting engagement and scope of work. Usually in large and international enterprises (>10.000 users) ALL-IP migration can be a complex and long-term project endeavour. In this blog post, I’d like to (quickly) point out on what to pay attention, too, besides the default information worker office telephony service enabling users to make/receive PSTN calls, forward calls to a PSTN phone number or enable simring between a soft client (e.g. SFB/Teams) and mobile phone…

Let’s dig in a bit deeper into large-scale ALL-IP (and VoIP) projects: Typically, international companies have almost everything you can (and might cannot yet) imagine in their PBX infrastructure. Therefore it’s essential to define targets and work packages as below first …

  • Source Architecture Analysis (as-is analysis)
    • … to discover
      • all assets …
      • all capability …
      • all configurations …
      • … linked to any of your PBXs, e.g. analog phones, digital phones, IP phones, DECT phones, …
    • … analyze
      • PBX configurations …
      • … to check for any special devices connecting to PSTN, e.g. modems, alarm server, intrusion detection system, card terminals …
  • Target Architecture Development
    • Digital workplace vision and strategy
      • …
      • ALL-IP
      • …
    • Digital workplace architecture
      • …
      • Telephony Services (ALL-IP as a part of the digital workplace)
        • PBX (global PBX infrastructure)
        • PSTN (global PSTN access)
      • …
  • (Telephony Services) Migration Architecture Development
    • …
    • migration strategy and plan development
      • Global ALL-IP strategy and plan
      • migration strategy and plan for non-ALL-IP-compliant devices
    • …
  • Service Operations Architecture
    • …
    • utilize a document or configuration management system to store all gathered contracts/details/configurations/… (operative process because it might change over time …)
    • …

For large infrastructure it helps to split up the project at least into two (parallel) work streams or sub-projects (if possible), for instance:

  • Global PSTN access
    • ~”external voice connectivity”
    • This sub-project has to focus on PSTN connecivity on a global scale.
    • Global PSTN carrier / provider management
    • Global PSTN provider / PSTN SIP Trunk Architecture Concept
    • Comply with national telecommunication regulations and laws
    • Simplify global PSTN access infrastructure
      • Define a clear PSTN access / feature list
      • Consolidation of PSTN access
      • Centralization of PSTN SIP trunks (if possible)
      • High Availability
    • Simplify global PBX infrastructure connectivity
    • Consider different PSTN sourcing options
  • Global PBX infrastructure
    • ~”internal voice connectivity”
    • This sub-project has to focus on PBX infrastructure on a global scale, too.
    • Assess site / work space requirements
    • Assess user (group) requirements
    • Define and establish standards per site and user profile/s
      • Example user groups: office worker, production worker, indoor mobile worker, outdoor mobile worker …
      • Example site / work space (profiles): production plant, logistics, warehouse, sales office, R&D, administration, …
    • Migrate all non-IP endpoints to IP (based on the previous discovery)
    • Simplify global PBX infrastructure
      • Single PBX vendor or service
      • Reduce legacy endpoints if applicable
      • Consolidate PBX
      • Centralize PBX
      • High Availability
    • Simplify global PSTN access connectivity
    • Consider different PBX sourcing options

The above description is a high-level summary on typical things to keep in mind for telephony services as part of a digital workplace architecture. I hope it might guide you a little towards some telephony and ALL-IP hot spots to be aware of. Furthermore you can find more to read regarding to ALL-IP and special voice services below…

Further resources