Monitor T3 Interfaces
This section includes the following information to assist you when troubleshooting T3 interfaces:
Checklist for Monitoring T3 Interfaces
Purpose
To monitor T3 interfaces and begin the process of isolating T3 interface problems when they occur.
Action
Table 1 provides the links and commands for monitoring T3 interfaces.
Table 1: Checklist for Monitoring T3 Interfaces
Tasks | Command or Action |
|---|---|
| Monitor T3 Interfaces | |
show interfaces terse t3* | |
show interfaces t3-fpc/pic/port | |
show interfaces t3-fpc/pic/port extensive | |
monitor interface t3-fpc/pic/port | |
Monitor T3 Interfaces
By monitoring T3 interfaces, you begin the process of isolating T3 interface problems when they occur.
To monitor T3 interfaces, follow these steps:
- Display the Status of T3 Interfaces
- Display the Status of a Specific T3 Interface
- Display Extensive Status Information for a Specific T3 Interface
- Monitor Statistics for a T3 Interface
Display the Status of T3 Interfaces
Purpose
To display the status of T3 interfaces, use the following Junos OS command-line interface (CLI) operational mode command:
Action
Sample Output
user@host> show interfaces terse t3*Interface Admin Link Proto Local Remote t3-1/0/0 down up - administratively disabled t3-1/0/0.0 up down inet 1.1.1.1/30 t3-1/0/1 up down t3-1/0/1.0 up down inet 2.2.2.2/30 - link layer down t3-1/0/2 up up t3-1/0/2.0 up up inet 3.3.3.3/30 - link layer up t3-1/0/3 up down
Meaning
The sample output shows the status of both the physical and logical interfaces. See Table 2 for a description of what the output means.
Table 2: Status of T3 Interfaces
Physical Interface | Logical Interface | Status Description |
|---|---|---|
t3-1/0/0 Admin Down Link Up | t3-1/0/0.0 Admin Up Link Down | This interface is administratively disabled and the physical link is healthy (Link Up), but the logical interface is not established. The logical interface is down because the physical link is disabled (Link Down). |
t3-1/0/1 Admin Up Link Down | t3-1/0/1.0 Admin Up Link Down | This interface is not functioning between the local router and the remote router because both the physical and logical links are down (Link Down). The interface is not administratively disabled because both the physical and logical links are up (Admin Up). |
t3-1/0/2 Admin Up Link Up | t3-1/0/2.0 Admin Up Link Up | This interface has both the physical and logical links up and running. |
t3-1/0/3 Admin Up Link Down | This interface does not have a logical link configured. |
Display the Status of a Specific T3 Interface
Purpose
To display the status of a specific T3 interface when you need to investigate its status further, use the following Junos OS CLI operational mode command:
Action
Sample Output
user@host> show interfaces t3-1/0/0 Physical interface: t3-1/0/0, Enabled, Physical link is Down
Interface index: 9, SNMP ifIndex: 10
Link-level type: Cisco-HDLC, MTU: 4474, Clocking: Internal
Speed: T3, Loopback: None, CRC: 16, Mode: C/Bit parity
Device flags : Present Running Down
Interface flags: Hardware-Down Link-Layer-Down Point-To-Point SNMP-Traps
Link flags : Keepalives
Keepalive Input: 116 (00:02:32 ago), Output: 185 (00:00:02 ago)
Input rate : 0 bps (0 pps), Output rate: 0 bps (0 pps)
Active alarms : LOF, LOS
Active defects : LOF, LOS
Logical interface t3-1/0/0.0 (Index 12) (SNMP ifIndex 32)
Flags: Device-down Point-To-Point SNMP-Traps, Encapsulation: Cisco-HDLC
Protocol inet, MTU: 4470
Addresses, Flags: Dest-route-down Is-Preferred Is-Primary
Destination: 1.1.1.0/30, Local: 1.1.1.1
Meaning
The first line of the sample output shows the status of the link. If this line shows that the physical link is up, the physical link is healthy and can pass packets. If this line shows that the physical link is down, the physical link is unhealthy and cannot pass packets.
Display Extensive Status Information for a Specific T3 Interface
Purpose
To display extensive status information about a specific T3 interface, use the following Junos OS CLI operational mode command:
Action
Sample Output
user@router> show interfaces t3-1/0/0 extensivePhysical interface: t3-1/0/0, Enabled, Physical link is Down
Interface index: 9, SNMP ifIndex: 10
Link-level type: Cisco-HDLC, MTU: 4474, Clocking: Internal
Speed: T3, Loopback: None, CRC: 16, Mode: C/Bit parity
Device flags : Present Running Down
Interface flags: Hardware-Down Link-Layer-Down Point-To-Point SNMP-Traps
Link flags : Keepalives
Keepalive statistics:
Input : 116 (last seen 00:02:59 ago)
Output: 187 (last seen 00:00:09 ago)
Statistics last cleared: Never
Traffic statistics:
Input bytes : 2552 0 bps
Output bytes : 3703 0 bps
Input packets: 116 0 pps
Output packets: 161 0 pps
Input errors: - Input errors
Errors: 0, Drops: 0, Framing errors: 229, Policed discards: 1
L3 incompletes: 0, L2 channel errors: 0, L2 mismatch timeouts: 0
SRAM errors: 0, HS link CRC errors: 0
Output errors: - Output errors
Carrier transitions: 4, Errors: 0, Drops: 0, Aged packets: 0
Active alarms : LOF, LOS - DS3 active alarms and defects
Active defects : LOF, LOS
DS3 Media: Seconds Count State - T3 media-specific errors
PLL Lock 0 0 OK
Reframing 273 2 Defect Active
AIS 0 0 OK
LOF 273 2 Defect Active
LOS 273 2 Defect Active
IDLE 0 0 OK
YELLOW 0 0 OK
BPV 0 0
EXZ 0 0
LCV 275 18022125
PCV 0 0
CCV 0 0
LES 275
PES 273
PSES 273
CES 273
CSES 273
SEFS 273
UAS 277
HDLC configuration:
Policing bucket: Disabled
Shaping bucket : Disabled
Giant threshold: 4484, Runt threshold: 3
DSU configuration:
Compatibility mode: None, Scrambling: Disabled, Subrate: Disabled
FEAC loopback: Inactive, Response: Disabled, Count: 0
BERT time period: 10 seconds, Elapsed: 0 seconds
Algorithm: 2^3 - 1, Pseudorandom (1), Error rate: 10e-0
PFE configuration:
Destination slot: 1, Stream number: 0, PLP byte: 1 (0x00)
COS transmit queue bandwidth:
Queue0: 95, Queue1: 0, Queue2: 0, Queue3: 5
COS weighted round robin:
Queue0: 95, Queue1: 0, Queue2: 0, Queue3: 5
Logical interface t3-1/0/0.0 (Index 12) (SNMP ifIndex 32)
Flags: Device-down Point-To-Point SNMP-Traps, Encapsulation: Cisco-HDLC
Protocol inet, MTU: 4470, Flags: None
Addresses, Flags: Dest-route-down Is-Preferred Is-Primary
Destination: 1.1.1.0/30, Local: 1.1.1.1, Broadcast: Unspecified
Meaning
The sample output shows where the errors might be occurring. Look at the active alarms and active defects for the T3 interface and investigate the T3 media accordingly. See Checklist of Common T3 Alarms and Errors for an explanation of T3 alarms.
Monitor Statistics for a T3 Interface
Purpose
To monitor statistics for a T3 interface, use the following Junos OS CLI operational mode command:
Action
Sample Output
user@host> monitor interface t3-1/0/0router Seconds: 78 Time: 21:44:15 Interface: t3-1/0/0, Enabled, Link is Down Encapsulation: Cisco-HDLC, Keepalives, Speed: T3 Traffic statistics: Current Delta Input bytes: 0 (0 bps) [0] Output bytes: 207 (184 bps) [184] Input packets: 0 (0 pps) [0] Output packets: 9 (1 pps) [8] Encapsulation statistics: Input keepalives: 0 [0] Output keepalives: 9 [8] Error statistics: Input errors: 0 [0] Input drops: 0 [0] Input framing errors : 9 [8] CCV 0 [0] Interface warnings: o Received keepalive count is zero o Framing errors, check FCS, scrambling and subrate configuration Next='n', Quit='q' or ESC, Freeze='f', Thaw='t', Clear='c', Interface='i'
Meaning
This command checks for and displays common interface failures, indicates whether loopback is detected, and reports any increases in framing errors. Use the information from this command to narrow down possible causes of an interface problem.
 | Note: If you are accessing the router from the console connection, make sure you set the CLI terminal type using the set cli terminal command. |
Table 3 presents problem situations and actions to help you further understand the problem.
Table 3: Problem Situations and Actions
Problem Situation | Action |
|---|---|
Framing errors are increasing. | Check the frame check sequence (FCS), scrambling, and subrate configuration. |
Framing errors are increasing, and the configuration is correct. | Check the cabling to the router and have the carrier verify the integrity of the line. |
Input errors are increasing. | Check the cabling to the router and have the carrier verify the integrity of the line. |
| Note: We recommend that you use this command only for troubleshooting purposes. Do not leave it on during normal router operations because real-time monitoring of traffic consumes additional CPU and memory resources. |
