[cisco-voip] IUA backhaul with back-to-back AS5300s

[Oleksandr Lytvyn]

Hi!

We're trying to set up a lab environment with two AS5300 connected
back-to-back
with T1, with PRI over that T1 and two Call Agents (non-Cisco) with MGCP and
PRI IUA (so that VoIP calls from one Call Agent are routed to one AS5300, go
through PRI to another AS5300 and to VoIP could controlled by another Call
Agent).

I configured both AS5300 with IUA and SCTP, configured PRI like:

<...>
controller T1 2
 framing esf
 linecode b8zs
 pri-group timeslots 1-24 service mgcp
!
interface Serial2:23
 no ip address
 isdn switch-type primary-ni
 isdn bind-l3 iua-backhaul AS1
 no cdp enable
<...>

I also have " isdn protocol-emulate network" on one side (needed for
back-to-back
otherwise Layer 2 doesn't come to MULTIPLE_FRAME_ESTABLISHED).

Everything seems to be working up to the point when Call Agent sends IUA DL
Establish
Request. At that point, AS5300 sends SABME to the other party and receives
UAf. Then
(I assume) it should send DL Establish Confirm to the Call Agent. But that
doesn't happen.
Below's the excerpt from Cisco log. Notice "srl_send_l2_pak: 131072 protocol
not up" at
the end.

What might be the cause for that? What protocol is it complaining about?
>From the looks of it,
the device tries to actually send DL Establish Confirm to IUA, but is not
able to do it.

Any ideas?

Thanks,
Alex

Jul  2 14:35:43.051 EDT: IUA: received packet on ASP sm62gp01
Jul  2 14:35:43.051 EDT: IUA:    version 0x1
Jul  2 14:35:43.051 EDT: IUA:    message_type 0x5, msg_class 0x5
Jul  2 14:35:43.051 EDT: IUA:    total message length 24
Jul  2 14:35:43.051 EDT: IUA: 01 00 05 05 00 00 00 18 00 01 00 08 00 00 00
02
Jul  2 14:35:43.051 EDT: IUA: 00 05 00 08 00 FFFFFF80 00 00 FFFFFFD3
FFFFFF88 02 7C FFFFFF82 FFFFFFA4 FFFFFF82 FFFFFFBDIUA: Received EST-REQ for
interface 2

Jul  2 14:35:43.051 EDT: ISDN Se2:23 Q921d: handle_mail: setting pkt to NULL
Jul  2 14:35:43.051 EDT: ISDN Se2:23 LIFd: LIF_StartTimer: timer
(0x62BCB46C), ticks (1000), event (0x1240)
Jul  2 14:35:43.051 EDT: ISDN  Q921d: isdn_l2d_srq_process: QUEUE_EVENT
Jul  2 14:35:43.051 EDT: ISDN Se2:23 Q921: User TX -> SABMEp sapi=0 tei=0
Jul  2 14:35:43.055 EDT: ISDN  Q921d: isdn_l2d_srq_process: event_count 1
Jul  2 14:35:43.059 EDT: ISDN  Q921d: isdn_from_driver_process: QUEUE_EVENT
Jul  2 14:35:43.059 EDT: ISDN Se2:23 Q921: User RX <- UAf sapi=0 tei=0
Jul  2 14:35:43.059 EDT: ISDN Se2:23 Q921d: process_rxdata: Frame sent to L2
Jul  2 14:35:43.059 EDT: ISDN  Q921d: isdn_from_driver_process: event_count
1
Jul  2 14:35:43.059 EDT: ISDN Se2:23 Q921d: srl_send_l2_pak:
        source_id = Q.921, dest_id = IUA BACKHAUL, prim = DL_EST_CONF
        priv_len = 4 int_id = 0x62FA7DEC datasize = 16
Jul  2 14:35:43.059 EDT: ISDN Se2:23 Q921d: data =
0x62FA7DEC00020000020304B800011800
Jul  2 14:35:43.063 EDT:
Jul  2 14:35:43.063 EDT: ISDN Se2:23 **ERROR**: srl_send_l2_pak: 131072
protocol not up