1. Configuration Guide
  2. External Policy Servers
  3. IPv6 Support

IPv6 Support

The Oracle Communications Session Border Controller supports Diameter-based CLF and RACF external policy servers in both IPv4 and IPv6 networks. There are three areas of enhanced functionality where the Oracle Communications Session Border Controller’s Diameter external policy server offerings have changed.

  • AVP support of IPv6 addresses encoded in UTF-8 format

  • Extra bandwidth allocation in policed flows to compensate for longer addresses

  • Framed-IPv6-Prefix AVP (97) support

IPv6 Addresses in UTF-8 Format

When necessary, the Oracle Communications Session Border Controllerchecks that IPv6 addresses are formatted correctly in UTF-8 when they are inserted into relevant AVPs. The applicable AVPs are

  • Flow-Description AVP (507)
  • Subscription-Id-Data AVP (444)
  • Destination-Realm AVP (283) only if applicable

Framed-IPv6-Prefix AVP

The Oracle Communications Session Border Controller supports the Framed-IPv6-Prefix AVP (97) as defined in RFC4005.

The Diameter interface on the Oracle Communications Session Border Controller substitutes this AVP for the Framed-IP-Address AVP (8) in a Diameter message when carrying IPv6 addresses in the AVP.

The IP Address is encoded as Octet-String. Although the IPv6 address is a 128 bit number, it will not fall on a 4 byte boundary due to the formatting of this particular AVP. Additional whitespace will be added per RFC 3588 to the end of the octet-string to pad the ending of the AVP.

Bandwidth Allocation Compensation for IPv6

Transporting IPv6 packets requires extra bandwidth because of their larger packet size. This needs to be taken into account when allocating bandwidth and policing media. In order to reserve the necessary bandwidth for signaling messages, the standard pkt rate parameter has been added to the media profile configuration element.

The Oracle Communications Session Border Controller needs a baseline media packet size for bandwidth requests. It first checks if the SDP includes a ptime value. That value will be used as the baseline if present in the request. If this value is not included in the SDP, the standard pkt rate parameter is used as the baseline. The chosen value is then multiplied times 20 (the difference between an IPv4 and IPv6 packet).

This value is sent to the external policy server in the bandwidth request when sending media into an IPv6 realm. From that point it is used when allocating bandwidth or media policing.

Bandwidth Requests while Transcoding

The Oracle Communications Session Border Controller can evaluate transcoding and IPv4 to IPv6 call scenarios and mitigate between end stations and policy servers to request appropriate bandwidth.

Two behaviors better assure proper bandwidth requests:

  • AAR bandwidth requests for transcoded calls—The Oracle Communications Session Border Controller uses the SDP sent or received on the same realm as the external policy server to calculate the bandwidth information it presents in an AAR. This ensures that the Oracle Communications Session Border Controller receives bandwidth allocation information that is applicable to the leg that the policy server is serving.
  • AAR bandwidth requests for dual stack calls—If the Oracle Communications Session Border Controller receives a call that switches between IPv4 and IPv6, the bandwidth that it presents in the AAR is based on the address space used by the call on the same realm as the external policy server. This ensures that the Oracle Communications Session Border Controller receives bandwidth allocation information that is applicable to the leg that the policy server is serving.