0 Fr Loss Secs, 1 Line Err Secs, 0 Degraded Mins 1 Errored Secs, 1 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs Chapter 20: T1 Data in Interval 2: 255 Line Code Violations, 255 Path Code Violations 32 Slip Secs, 109 Fr Loss Secs, 34 Line Err Secs, 0 Degraded Mins 0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 116 Unavail Secs Data in Interval 3: 0 Line Code Violations, 0 Path Code Violations 0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs Data in Interval 4: 0 Line Code Violations, 0 Path Code Violations 0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins 0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs The first paragraph shows the combined totals for all the intervals in memory. The maximum amount of time for which the CSU/DSU will record events is 24 hours (96 15-minute intervals), at which point the oldest interval's data is discarded. The out- put is arranged by interval, not by something more obvious like actual time. This is a throwback to the way standalone CSU/DSUs reported historical information. The first interval listed is the current interval. The next interval, numbered as Interval 1, is the most recent interval. The intervals increment until they reach 96. When looking at this information, search for patterns. If you see a number of line code violations, or any other error that shows up in all or most of the intervals, you've got a problem. Note that you will see errors when a T1 bounces for any rea- son. Interval 2 in the preceding output shows some pretty severe errors, which are the result of me unplugging the T1 cable from the jack. If you're seeing errors incrementing, start troubleshooting, and remember: physical layer first! Most problems are caused by a bad cable or piece of equipment. Configuring T1s CHAPTER 21 I'm going to treat DS3s a little differently than I did Tls. While I believe knowledge of T1 framing and signaling is useful for a network engineer, I 