Avamprogetto 2b

In-house handover points require the hosting of third-party equipment by the owner of the premises (co-location). An advantage is that the connecting link can be kept short, which makes troubleshooting easier in the case of breakdowns and allows for physical protection against unauthorised access (e.g. cage).

In-span handover points generally require longer connecting links, possibly with cable ducts, splices, etc. Troubleshooting takes longer in the case of a breakdown, and physical protection against unauthorised access is generally only possible if the handover point is in the same building.

Note on Figure 4, Figure 5 and Figure 6: These figures give no guidelines for the connection between the LEMF primary system and secondary system. From the CSP’s point of view, there is only one LEMF system. Aspects regarding failover (minimising the impact if the primary system breaks down) and the forwarding of information to the LEMF secondary system are not described here. Likewise, no guidelines are given on how to implement at the CSP end the transition from the MD to the NE, which serves as a gateway to the delivery network.

Figure 4 shows an approach for a delivery network based on an upper and a lower stratum. The upper stratum has the lower stratum under its control, as higher protocol layers between the MD and the LEMF are in one hand. The LEMF "sees" only the upper stratum, which falls under the responsibility of the CSP supposed to deliver the interception results.

The LI-HP and DN-HP of a CSP are coincident, which, in the event of an error, requires a triage in a two-part relationship (CSP/Upper Stratum Provider and the PTSS). If the lower stratum is provided by a third party, here too there is a two-part relationship (CSP/Upper Stratum Provider and Lower Stratum Provider).

A typical example of such an approach is a fibre optics network, separated by WDM filters (lower stratum) and an upper stratum per CSP consisting of a network using an allocated wavelength (one possible implementation for such a DN is sub-variant B1 “Shared fibre infrastructure” of IP DN delivery variant B).

Upper CSP Stratum PTSS Domain Domain HP HP HP HP in-house in-house in-house NE NE NE NE NE LEMF

point-to-

Lower point MD HP vs. HP HP Stratum HP in-house in-house in-house NE NE NE meshed NE NE LEMF

Under responsibility of lower Stratum provider LI-HP and Under responsibility of upper Stratum provider DN-HP coincident

Figure 4 Stratified delivery network

Figure 5 and Figure 6 show an approach for a delivery network based on concatenated subnetworks. These sub-networks can have a different top protocol layer.