3.2. Planning ChecklistsΒΆ

This section provides you with a summary of questions raised in the previous section. We urge that you dilligently check all the items before you proceed with commencing an installation.


  • Have you identified all Call Agents present in your network?
  • Have you specified additional processing rules for these Call Agents, such as network limits?
  • Have you grouped all Call Agents in Realms present in your network?
  • Have you specified additional processing rules for these Call Agents such as network limits?
  • Have you specified all physical interfaces (Ethernet cards)?
  • Have you specified all IP addresses, port ranges, and VLANs to  be used on these interfaces?
  • If there are firewalls in front of the SBC, have you verified that all needed ports are open?
  • Have you verified that IP rules on the SBC restrict traffic to  privileged ports from trusted IP addresses only?

SBC Logic

  • Have you devised the SIP routing criteria used in your network? How many routing rules do you anticipate?
  • Have you devised the routing flows between Realms and CAs?
  • Does any of the conditions mentioned necessitate use of media relays?
  • If you need to restrict codecs, which codecs shall be permitted and which codecs shall be restricted?
  • Do you need to force use of a codec unsupported by a CA using transcoding? Which codec?
  • If your SIP traffic includes REGISTER messages, will you enable registrar cache? If so, what will be the registration interval?
  • Does presence of clients behind NATs necessitate use of media-relay, symmetric SIP and registrar-cache?
  • Do you plan to set up high-available SBC pair(s)?
  • If you use the high-available (HA) SBC pair, do you plan to use an administrative network for the HA protocol?
  • If you need to handle downstream failover, have you devised appropriate DNS maps?
  • Does the SBC accept traffic using different dialling conventions? If so, how will you translate between them?


  • What conditions do you devise to drop illegitimate traffic? Will you configure IP-based and/or URI-based blacklists?
  • Will you introduce traffic shaping limits: call-rate, call-length, parallel calls and maximum call-length?
  • Will all or only registered SIP devices be permitted to make phone calls?
  • Will the need to troubleshoot your network easily or the need to hide topology prevail?


  • How many SBCs do you need?
  • How many network cards shall each SBC have?
  • How many IP addresses do you need?
  • How much bandwidth do you need in each direction?


  • Do you plan to use the management components over a dedicated administrative network?
  • Is external session decision-making logic using RESTful interface needed? If so, what are the parameters passed from and to the RESTful server?
  • Is SNMP monitoring needed? If so, what is the SNMP configuration data (IP address, SNMP community)?
  • Do you need to mass-provision some configuration data? What is the structure of the data and what size of tables do you anticipate?
  • Do you need to record audio and access it? What is your deletion and retention policy for the stored audio files?
  • Do you need to export CDRs?
  • Have you devised appropriate DNS SRV and A entries for all IP addresses?

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3.1. Network Planning Guidelines

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3.3. A Typical SBC Configuration Example

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