[nsp] P-bit and C-bit DS3 errors

[Scott Weeks]

: What are the usual suspects for error patterns like this
: (almost always clean, except for some short-lived error bursts)?

Clock slip?  Who's providing the timing?  Validate it by logging in and
looking.  I have seen folks on all sides of the fence saying, "I know x
for a fact" when a simple login proved otherwise WRT clocking.

scott



On Tue, 11 Nov 2003, Mark Kent wrote:

: I've got this scenario:
:
:                  ds3 x-conn        40 miles        OCx
:  7206/PA-MC-2T3+  --------> Cerent -------> Cerent ---> cisco 12016/GRP
:  12.0(25)S1                                             12.0(25)S2
:
: I run the 7206, an NSP runs the rest of the stuff.
: After an "upgrade" on the GSR, we've been experiencing hits on the
: DS3, like this:
:
: Nov 11 10:17:45: %CONTROLLER-5-UPDOWN: Controller T3 4/0, changed state to down
: Nov 11 10:17:46: %CONTROLLER-5-UPDOWN: Controller T3 4/0, changed state to up
: Nov 11 10:17:57: %CONTROLLER-5-UPDOWN: Controller T3 4/0, changed state to down
: Nov 11 10:17:58: %CONTROLLER-5-UPDOWN: Controller T3 4/0, changed state to up
: Nov 11 10:17:59: %CONTROLLER-5-UPDOWN: Controller T3 4/0, changed state to down
: Nov 11 10:18:00: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial4/0, changed state to down
: Nov 11 10:18:00: %CONTROLLER-5-UPDOWN: Controller T3 4/0, changed state to up
: Nov 11 10:18:01: %CONTROLLER-5-UPDOWN: Controller T3 4/0, changed state to down
: Nov 11 10:18:02: %CONTROLLER-5-UPDOWN: Controller T3 4/0, changed state to up
: Nov 11 10:18:04: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial4/0, changed state to up
:
:   INTERVAL      LCV   PCV   CCV   PES  PSES  SEFS   UAS   LES   CES  CSES
:   10:19-10:19     0     0     0     0     0     0     0     0     0     0
:   10:04-10:19     0   165   156     8     7     8     0     0     7     7
:   09:49-10:04     0     0     0     0     0     0     0     0     0     0
:
: So, we get P-bit code violations and C-bit code violations.
:
: These happen every few hours, sometimes clustered
: (three in twenty minutes is the current record).
: The circuit does not pick up errors at other times,
: it only gets these short-term hits.
:
: The NSP has not made any progress on figuring out what is happening.
: The circuit has been tested, but of course this is an intermittent problem
: and telcos don't do well with intermittent problems.
:
: I've swapped out everything on my end, all the way to the
: patch panel hand-off from the NSP.   I previously had a PA-T3,
: and swapped in the PA-MC-2T3+.
:
: With the PA-T3 the only info I got was the circuit was going down and
: the FEBE counter (far end block errors) went up during an event.
: The PA-MC-2T3+ gives more info (as above).
:
: What are the usual suspects for error patterns like this
: (almost always clean, except for some short-lived error bursts)?
:
: Thanks,
: -mark
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