Packetizer
H.323 vs SIP
  H.323 SIP H.248(Megaco)/MGCP
Hype None High None
Philosophy Unified Modular Unified
Complexity High High Moderate
Scope Full Limited Partial
Scalability Good Good N.A. (it's a tool for scalability)
PSTN Interworking Yes Somewhat Yes
SS7 Compatibility Good Poor Good
Cost Moderate Moderate Moderate
Message Size Small Large Moderate
Router Fragmentation Unlikely Likely Unlikely
Volatility of Standard Low High Low
Multimedia Good Poor Poor
Usage-Billing Fit Good Poor N.A.
Monthly Billable Call Minutes 1,000,000,000's 10,000s 100,000s