Verifying Link Services Interface Statistics

Purpose

Verify the link services interface statistics.

Action

The sample output provided in this section is based on the configurations provided in Configuring MLPPP Bundles and LFI on Serial Links. To verify that the constituent links are added to the bundle correctly and the packets are fragmented and transmitted correctly, take the following actions:

1. On Router R0 and Router R1, the two J-series routers used in this example, configure MLPPP and LFI as described in Configuring MLPPP Bundles and LFI on Serial Links.
2. From the CLI, enter the ping command to verify that a connection is established between R0 and R1.
3. Transmit 10 data packets, 200 bytes each, from R0 to R1.
4. On R0, from the CLI, enter the show interfaces interface-name statistics command.

Physical interface: ls-0/0/0, Enabled, Physical link is Up
  Interface index: 134, SNMP ifIndex: 29, Generation: 135
  Link-level type: LinkService, MTU: 1504
  Device flags   : Present Running
  Interface flags: Point-To-Point SNMP-Traps
  Last flapped   : 2006-06-23 11:36:23 PDT (03:38:43 ago)
  Statistics last cleared: 2006-06-23 15:13:12 PDT (00:01:54 ago)
  Traffic statistics:
   Input  bytes  :                    0                    0 bps
   Output bytes  :                 1820                    0 bps
   Input  packets:                    0                    0 pps
   Output packets:                   10                    0 pps
  ...
  Egress queues: 8 supported, 8 in use
  Queue counters:       Queued packets  Transmitted packets      Dropped packets
    0 DATA                          10                   10                    0
    1 expedited-fo                   0                    0                    0
    2 VOICE                          0                    0                    0
    3 NC                             0                    0                    0

  Logical interface ls-0/0/0.0 (Index 67) (SNMP ifIndex 41) (Generation 133)
    Flags: Point-To-Point SNMP-Traps 0x4000 Encapsulation: Multilink-PPP
    Bandwidth: 16mbps
    Bundle options:
      ....
      Drop timer period               0
      Sequence number format          long (24 bits)
      Fragmentation threshold         128
      Links needed to sustain bundle  1
      Interleave fragments            Enabled
    Bundle errors:
      Packet drops                    0 (0 bytes)
      Fragment drops                  0 (0 bytes)
     ...
    Statistics         Frames        fps         Bytes          bps
    Bundle:
      Fragments:
        Input :             0          0             0            0
        Output:            20          0          1920            0
      Packets:
        Input :             0          0             0            0
        Output:            10          0          1820            0
    Link:
      se-1/0/0.0
        Input :             0          0             0            0
        Output:            10          0          1320            0
      se-1/0/1.0
        Input :             0          0             0            0
        Output:            10          0           600            0
  ...
      Destination: 10.0.0.9/24, Local: 10.0.0.10, Broadcast: Unspecified, Generation:144

What it Means

This output shows a summary of interface information. Verify the following information:

• Physical interface—The physical interface is Enabled. If the interface is shown as Disabled, do either of the following:
  • In the CLI configuration editor, delete the disable statement at the [edit interfaces interface-name] level of the configuration hierarchy.
  • In the J-Web configuration editor, clear the Disable check box on the Interfaces>interface-name page.
• Physical link—The physical link is Up. A link state of Down indicates a problem with the interface module, interface port, or physical connection (link-layer errors).
• Last flapped—The Last Flapped time is an expected value. The Last Flapped time indicates the last time the physical interface became unavailable and then available again. Unexpected flapping indicates likely link-layer errors.
• Traffic statistics—Number and rate of bytes and packets received and transmitted on the interface. Verify that the number of inbound and outbound bytes and packets match the expected throughput for the physical interface. To clear the statistics and see only new changes, use the clear interfaces statistics interface-name command.
• Queue counters—Name and number of queues are as configured. This sample output shows that 10 data packets were transmitted and no packets were dropped.
• Logical interface—Name of the multilink bundle you configured—ls-0/0/0.0.
• Bundle options—Fragmentation threshold is correctly configured, and fragment interleaving is enabled.
• Bundle errors—Any packets and fragments dropped by the bundle.
• Statistics—The fragments and packets are received and transmitted correctly by the router. All references to traffic direction (input or output) are defined with respect to the router. Input fragments received by the router are assembled into input packets. Output packets are segmented into output fragments for transmission out of the router.

  In this example, 10 data packets of 200 bytes were transmitted. Because the fragmentation threshold is set to 128 bytes, all data packets were fragmented into two fragments. The sample output shows that 10 packets and 20 fragments were transmitted correctly.

• Link—The constituent links are added to this bundle and are receiving and transmitting fragments and packets correctly. The combined number of fragments transmitted on the constituent links must be equal to the number of fragments transmitted from the bundle. This sample output shows that the bundle transmitted 20 fragments and the two constituent links se-1/0/0.0 and se-1/0/1.0.0 correctly transmitted 10+10=20 fragments.
• Destination and Local—IP address of the remote side of the multilink bundle and the local side of the multilink bundle. This sample output shows that the destination address is the address on R1 and the local address is the address on R0.

Related Topics

For a complete description of show interfaces output, see the JUNOS Interfaces Command Reference.