Kirill Kucherov
2012-10-10, 02:42 AM
Hello, guys,
I have recently faced surprising problem with NSN RNC Dual Iub handling in case of IP failure:
There are several Flexi BTS with the following configuration:
ATM: VCI_1 - DCH+Stringent (for voice, signaling, common channel), VC_2 - DCH+Stringent Bi-level (for R99 NRT fallback)
IP: HSPA and NRT DCH (R99)
After IP failure subsribers experience NO service - even voice! - after 10 sec (if BFD is off - after 5 min). From the statistics I see the increase in FACH-u load - but only up to 3,1 kbps, no traffic in VCI_2 and almost any changes within the load of VCI_1.
At the same time, if I have on-going call during the porblem, it is not dropped! I can finish my call with no regards to its duration. After that user under that NodeB cannot make any call. Registraion is being failed as well. In few words - all new Dedicated RB establishment attempts (even SRBs) are failed.
At the same time - under test NodeB conditions with no load - there is no such problem.
Have two ideas:
1. radio FACH (i.e. SCCPCH) overload (seems unreal)
2. Wrong functioning of MAC-c regaring prioritisation of FACH-c and, as a consequence, FACH overload by user traffic redirected to MAC-c from MAC-d as a result of RNC thinks there is no transport bearer for Dedicated channels.
Has anybody experienced the same problem? Or at least, have some ideas?
Thanks in advance!
I have recently faced surprising problem with NSN RNC Dual Iub handling in case of IP failure:
There are several Flexi BTS with the following configuration:
ATM: VCI_1 - DCH+Stringent (for voice, signaling, common channel), VC_2 - DCH+Stringent Bi-level (for R99 NRT fallback)
IP: HSPA and NRT DCH (R99)
After IP failure subsribers experience NO service - even voice! - after 10 sec (if BFD is off - after 5 min). From the statistics I see the increase in FACH-u load - but only up to 3,1 kbps, no traffic in VCI_2 and almost any changes within the load of VCI_1.
At the same time, if I have on-going call during the porblem, it is not dropped! I can finish my call with no regards to its duration. After that user under that NodeB cannot make any call. Registraion is being failed as well. In few words - all new Dedicated RB establishment attempts (even SRBs) are failed.
At the same time - under test NodeB conditions with no load - there is no such problem.
Have two ideas:
1. radio FACH (i.e. SCCPCH) overload (seems unreal)
2. Wrong functioning of MAC-c regaring prioritisation of FACH-c and, as a consequence, FACH overload by user traffic redirected to MAC-c from MAC-d as a result of RNC thinks there is no transport bearer for Dedicated channels.
Has anybody experienced the same problem? Or at least, have some ideas?
Thanks in advance!