Table of Contents
What are line code violations?
Line Coding Violation (LCV) Error Event A Line Coding Violation (LCV) is the occurrence of either a Bipolar Violation (BPV) or Excessive Zeroes (EXZ) Error Event.
What causes T1 slips?
Core Issue. A router with multiple Primary Rate Interfaces (PRIs) can experience slip errors on one of the T1 PRIs. This happens when you have multiple clock sources.
What are slip seconds?
A Controlled Slip Second is a one-second interval containing one or more controlled slips. A Controlled Slip is the replication or deletion of the payload bits of a digital signal level 1 (DS1) frame.
What is a yellow alarm T1?
Description: An incoming yellow alarm indicates that the T1 network element connected to the T1 interface has a problem with the signal it is receiving from the T1 interface.
What is Rai detected?
RAI means Remote Alarm Indication and it happens when the circuit is fine but the device on the other end was disconnected or out of service, or like in your case, flapping between RAI and normal. This indicates a serious problem indeed. you have no problem on you side.
What is a Los alarm?
Description: A loss of signal (LOS) or loss of frame (LOF) alarm indicates that a signal could not be detected at the T1 interface.
What causes CRC errors on a T1?
Cyclic Redundancy Check (CRC) errors occur when the CRC calculation does not pass. This indicates that data is corrupted. This issue occurs for one of these reasons: The serial line is noisy.
What is soft loopback?
Soft loopback testing is accomplished with a set of Cisco IOS® software configuration commands on the Cisco gateway. The commands cause the WAN interface card (WIC) driver to automatically send traffic back towards the sending T1/E1 port.
What is a T1 blue alarm?
The third major alarm, the blue alarm, is also known as the alarm indication signal (AIS) and as a keep-alive signal. It is characterized by a continuous stream of unframed 1s. A T1 node that receives the AIS sends out the yellow alarm signal.
What causes runts and input errors?
What Causes Runts. There are a number of possible causes of runts, none which should occur on a normal, healthy network! The most likely causes are excessive collisions, which may distort Ethernet frames, causing only the first half of a frame to be seen before it is cut off by a collision.
What is port test loop?
Techopedia Explains Loopback Test A loop plug, called a wrap plug, is inserted into the port of a communication device to facilitate the loopback test. Loopback tests can readily be used to test computer serial ports and radio interfaces, and are one of the easiest ways to verify RS-232 communications.
What does a yellow alarm mean?
Yellow alarm, also known as remote alarm indication (RAI), indicates reception of a data or framing pattern that reports the far end is in red alarm. The alarm is carried differently in SF (D4) and ESF (D5) framing.
What causes giants Cisco?
Per Cisco the giant frames were caused by the dot1q header causing the Frames to exceed the 1500 bytes MTU size by causing the Frame to be 1522 bytes. From Cisco TAC: The counters for the giant do not indicate any error however are just informational.
Why do we need loopback test?
A loopback test is the process of sending digital data streams from a source back to the same point without any intentional modifications. It’s generally performed to determine whether a device works properly and whether there are failing nodes in a network.
What is a serial loopback?
A loopback test can verify the operation of serial communication by sending and receiving data from the same serial port. It can show problems in the serial port, the cable, or the software generating the messages without having to connect to third-party hardware.
What does a T1 red alarm indicate?
When a T1 device receives errors beyond a sometimes-configurable threshold, it declares a red alarm condition. Often two or three seconds of continuous LOS or OOF will trigger a red alarm. In this case, the device immediately attempts to transmit a code that signals the opposite end to declare a yellow alarm condition.
What does triangle mean on alarm?
The yellow triangle means that your alarm system is experiencing a trouble condition. This could be caused by a number of different possible factors, such as a low battery, an activated tamper or communication problems.
What is a runt Cisco?
On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data. Runts are Ethernet packets that are less than 64 bytes and may be caused by excessive collisions.