Avamprogetto 2b

7.2.2 Capacity requirements for the CS DN

Three parameters have an influence on the capacity of the CS DN:

i. Number of real-time CS interceptions

ii. Number of CC links required per target session

iii. Activity of the target

The value of i) shall be agreed bilaterally between the PTSS and the CSP. The value of ii) is generally two CC links in the case of CS (forward and reverse channel of the target). The value of iii) is an indication of the activity, based on the CSP’s measurements or statistics. The CSPs themselves ensure that there is sufficient delivery capacity available at their DN-HP to the CS DN.

The PTSS is responsible for ensuring that there is sufficient delivery capacity available at the DN-HP from the CS DN to the LEMF for all CSP deliveries. As the CS DN is a “virtual” network within the universal service licensee’s ISDN and the LI traffic, including interconnect traffic, is a small part of the overall volume, the bottleneck lies at the DN-HP end from the CS DN to the LEMF, i.e. the number of ISDN-PRAs to the LEMF. It is up to the PTSS to determine this number of ISDN-PRAs, as the PTSS is the only organisational unit with an overview of the values of each CSP, taking account of the trunking gain (common ISDN-PRAs vs. dedicated ISDN-PRAs per CSP). Scalability is ensured by adapting the number of ISDN-PRAs to the LEMF.

8 IP delivery networks

8.1 Capacity (bandwidth) of the IP DN

The dimensioning of the DNs shall be agreed bilaterally between the PTSS and the CSP. The bandwidth of a DN must be large enough to deliver the interception data including overhead on time and without any information loss resulting from traffic overload in the DN.

8.2 Variants of IP delivery networks

The variant ultimately chosen by a CSP must be agreed upon with the PTSS.

There are currently two variants of the IP DN:

A) OpenVPN

B) Direct connection of a CSP to the PTSS

In order to accommodate new requirements such as bi-directional transmission of Warrant Management data or Historical data, the IP DN variants shall be adapted accordingly.

8.2.1 IP DN Variant A: OpenVPN

Data transmission across public networks must be secured through encryption. OpenVPN has been chosen as the basic principle. The CSPs are not obliged to choose a particular commercial product or vendor as OpenVPN is available as an open source software solution.

The CSP shall set up one or more individual VPN tunnels to the LEMF. The PTSS is the single point of contact (SPOC) for the CSP.

The CSP shall acquire its VPN clients at its own discretion.

The FOITT is the provider of IP DN Variant A. The CSP manages the connections with the FOITT and arranges for the required service level through Service Level Agreements with its peering partner or upstream provider.