During the past months, the primary focus in the project was on setting up reliable ISDN PRI services via the OCTOI protocol and the related hub ("central office").
Today, we've tested yet another service over OCTOI: IP in HDLC. This broadband technology doesn't use individual 64kbps E1 timeslots like in ISDN, bug it aggregates the entire 31 timeslots of the E1 link (exept for TS0) into one fat HDLC pipe. It is customary to either put raw IP packets, or Ethernet packets, or PPP frames or even Frame_Relay into that HDLC. These method of operation is supported by a variety of routers from the 1990ies.
We've tested two configurations:
Pysical E1 on client side, virtual E1 (dahdi-trunkdev) on hub side¶
In this configuration, an overall inner RTT of 150ms was achieved, a 115ms increase compared to the native underlying IP link.
virtual E1 (dahdi-trunkdev) on both client and hub side¶
In this configuration, an overall inner RTT of 108ms was achieved, a 73ms increase compared to the native underlying IP link.