CUCM Architecture: Call Processing Models

Single Site Call Processing Model (Single Cluster)

  • All devices in a single, campus network
  • All incoming/outgoing calls go the PSTN
  • Use G.711 Uncompressed Audio Codecs
  • Simplest model to deploy

Central Call Processing Model (Single Cluster)

  • Remote phones supported by single cluster
  • PSTN and WAN connection at each site
  • G.72 Compressed CODEC between sites
  • SRST on remote routers

Distributed Call Processing Model (Multiple Clusters)

  • WAN Primary Path for intersite calls
  • G.729 codec over WAN
  • Independant WAN bandwidth control (H.323 gatekeeper or SIP Proxy)
  • The future of networks

Clustering over the WAN

  • Single point of administration
  • Database replicated
  • Features, shared lines over WAN
  • Higher requirements
  • Round Trip Delay: 40ms
  • Bandwidth: 900Kbps per 10,000 BHCA