busy hangup HDLC Bad FCS (8) on Primary D-channel

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Asterisk Users 9 Comments

Hi all,

After running fine for a few months now asterisk seems to hang
frequently , still functioning but the DAHDI channels seem busy (users
report a busy signal when calling or being called)

A reboot will allow it to run for another day or maybe 2 or 3 till the
problem occurs again.

running stock Asterisk 1.6.2.9-2+squeeze2 on Debian with stock kernel
2.6.32-5-686

i get the following errors:
pri_dchannel: PRI got event: HDLC Bad FCS (8) on Primary D-channel of span 2

(happens on all 4 spans)

and the following in dmesg:
[ 9004.635323] NOTICE-xpd_bri: XBUS-00/XPD-01: D-Chan RX DROP: BADFCS: 252
[ 9004.635332] NOTICE-xpd_bri: XBUS-00/XPD-01: D-Chan RX: current
packet[0..2]: 55 55 FC
[ 9004.635340] NOTICE-xpd_bri: XBUS-00/XPD-01: Multibyte Drop: errno=-71

Channel 0/1, span 1 got hangup, cause 18

According to my searching on the web the last two weeks i understand
that the first mentioned error can indicate a wrong configuration
setting or buggy hardware.

Have tried many options but the dahdi config as copied over from the
same machine (with elastix 1.4) seems the only one that seem to work

anybody has a clue?
much appreciated

some gory details below,

HARDWARE:
D201GLY2 motherboard
usb:001/002 xpp_usb+ e4e4:1162 Astribank-modular FPGA-firmware

DAHDI CONFIG:

dahdi-channels.conf

; Span 1: XBUS-00/XPD-00 “Xorcom XPD #00/00: BRI_TE” (MASTER)
group=0,11
context=from-pstn
switchtype = euroisdn
signalling = bri_cpe_ptmp
channel => 1-2
context = default
group = 63

; Span 2: XBUS-00/XPD-01 “Xorcom XPD #00/01: BRI_TE”
group=0,12
context=from-pstn
switchtype = euroisdn
signalling = bri_cpe_ptmp
channel => 4-5
context = default
group = 63

; Span 3: XBUS-00/XPD-02 “Xorcom XPD #00/02: BRI_TE”
group=0,13
context=from-pstn
switchtype = euroisdn
signalling = bri_cpe_ptmp
channel => 7-8
context = default
group = 63

; Span 4: XBUS-00/XPD-03 “Xorcom XPD #00/03: BRI_TE”
group=0,14
context=from-pstn
switchtype = euroisdn
signalling = bri_cpe_ptmp
channel => 10-11
context = default
group = 63

chan_dahdi.conf

[channels]
context=from-pstn
signalling=fxs_ks
rxwink=300 ; Atlas seems to use long (250ms) winks
pridialplan=local
prilocaldialplan=local
usecallerid=yes
hidecallerid=no
callwaiting=yes
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
canpark=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=no
faxdetect=incoming
echotraining=800
rxgain=0.0
txgain=0.0
callgroup=1
pickupgroup=1
;Uncomment these lines if you have problems with the disconection of
your analog lines
;busydetect=yes
;busycount=3
immediate=no

9 thoughts on - busy hangup HDLC Bad FCS (8) on Primary D-channel

  • Your telco provider has crc on or off , that is not matching with your
    server cross check with them.
    and this problem solve 4 problems

  • Is this happening in the middle of a call? Or only a while after the
    call ended?

  • there seems to be a relation indeed, have seen them happen randomly
    quite spurious, but they indeed tend to happen a while after the call is
    made.

  • A while after a call is made? A while after a call is ended?

    Maybe the provider intentionally sets layer 1 down (“to save power”)?

    That makes sense on PtMP, though I was not aware of this being used on
    PtP.

  • kept an eye on this and it seems to happen after a call is ended (+- 25
    – 30 seconds) and only when dialed out, but not when another call is in
    progress.

    sounds logical with the behaviour mentioned above

    i’m clueless on this, telco is China Unicom btw

  • audio quality seems to be fine ( e.g. had no complaints about that)

    would these FCS errors cause the system to become unresponsive leading
    to “Channel 0/1, span 1 got hangup, cause 18” after a period of working
    fine, or is this an unrelated issue?

  • […] Asterisk FAQs » Blog Archive » busy hangup HDLC Bad FCS (8) on … [ ] NOTICE-xpd_bri: XBUS-00/XPD-01: Multibyte Drop: errno=-71. Channel 0/1, span 1 got hangup, cause 18. According to my searching on the web the last two weeks i understand that the first mentioned error can […]