Using Pathtrace

Pathtrace

The Pathtrace feature builds on the Traceroute feature to provide information about interfaces, such as ingress and egress interface names and the number of transmitted and received frames and errors, at each hop in the path between 2 devices in a fabric. Pathtrace provides an end-to-end view of the shortest path without the need to connect to individual switches and check the Fabric Shortest Path First (FSPF) topology hop by hop.

Pathtrace is used to trace the path from a switch on which the pathtrace command is run, to a destination device or all the devices in a destination domain. The Pathtrace feature works with the Fibre Channel, Fibre Channel over Ethernet (FCoE), and Fibre Channel over IP (FCIP) interfaces. Pathtrace collects information about the available paths within the fabric and provides information for devices along the shortest path. Pathtrace displays the source interface, destination interface, cost, speed, and other statistics when used with the detail keyword. The pathtrace command can also be used to display the reverse path information (from destination back to the source). If the destination cannot be reached, Pathtrace displays the device on which the connectivity terminated.

The statistics displayed for various types of interfaces are:

  • Fibre Channel interface—The statistics are displayed for the associated Fibre Channel interfaces.

  • Virtual Fibre Channel (VFC) interface—The statistics are displayed for the associated Ethernet interfaces.

  • Fibre Channel port channel—The statistics are displayed for port channels.

  • VFC port channel—The statistics are displayed for VFC port channels.

  • FCIP interface or FCIP port channel—The statistics are displayed for the FCIP interfaces or FCIP port channels.

Guidelines and Limitations for Pathtrace

  • Pathtrace is not supported on Cisco MDS switches that are operating in the Cisco NPV mode.

  • Pathtrace does not support interop mode.

  • Pathtrace is supported only on Cisco MDS switches and not on other vendor switches.

  • Pathtrace does not support virtual domains (Inter-VSAN Routing [IVR] for Pathtrace).

  • Pathtrace is not manageable via Simple Network Management Protocol (SNMP).

  • Pathtrace supports a maximum of 16 hops without the reverse option, and 8 hops with the reverse option.

  • Statistics are displayed only for egress interfaces.

  • Statistics for FCIP and FCIP port-channel interfaces are not displayed for devices in the path running Cisco MDS NX-OS Release 6.2(5).

Using Pathtrace or Pathtrace Multipath

To display per-hop interface information along the paths between 2 devices, run this command:

switch# pathtrace {domain id | fcid id} vsan id [[reverse] [detail] | [multipath]]

The following example shows how to trace the path between a switch in which the command is executed and an edge device, using the edge device's FCID:


switch# pathtrace fcid 0xca016c vsan 2000
The final destination port type is F_Port
------------------------------------------------------------------------
Hop Domain In-Port          Out-Port         Speed Cost  Switchname
------------------------------------------------------------------------
0   111    embedded         fc1/6            4G    250   switch1
1   202    fc1/6            fc1/1            2G    -     switch2
NOTE: The stats are displayed for the egress interface only

The following example shows how to trace both the forward path and the return path between a switch in which the command is executed and an edge device, using the edge device's FCID:


switch# pathtrace fcid 0xca016c vsan 2000 reverse
The final destination port type is F_Port
------------------------------------------------------------------------
Hop Domain In-Port          Out-Port         Speed Cost  Switchname
------------------------------------------------------------------------
0   111    embedded         fc1/6            4G    250   switch1
1   202    fc1/6            fc1/1            2G    -     switch2
2   202    embedded         fc1/6            4G    250   switch2
3   111    fc1/6            embedded         -     -     switch1
NOTE: The stats are displayed for the egress interface only

The following example shows how to display detailed information about the interfaces (both the forward path and the return path) between a switch in which the command is executed and an edge device, using the edge device's FCID:


switch# pathtrace fcid 0xca016c vsan 2000 reverse detail
The final destination port type is F_Port
-------------------------------------------------------------------------------
Hop 0       Domain In-Port          Out-Port         Speed Cost  Switchname
            111    embedded         fc1/6            4G    250   switch1
-------------------------------------------------------------------------------
Stats for egress port: fc1/6
    TxRt(B/s): 2944
    RxRt(B/s): 3632
        TxB_B: 32
        RxB_B: 32
      TxFrame: 137467
      RxFrame: 137475
       Errors: 0
      Discard: 0
          CRC: 0
-------------------------------------------------------------------------------
Hop 1       Domain In-Port          Out-Port         Speed Cost  Switchname
            202    fc1/6            fc1/1            2G    -     switch2
-------------------------------------------------------------------------------
Stats for egress port: fc1/1
    TxRt(B/s): 1424
    RxRt(B/s): 1528
        TxB_B: 0
        RxB_B: 32
      TxFrame: 711
      RxFrame: 649
       Errors: 0
      Discard: 15
          CRC: 0
-------------------------------------------------------------------------------
Hop 2       Domain In-Port          Out-Port         Speed Cost  Switchname
            202    embedded         fc1/6            4G    250   switch2
-------------------------------------------------------------------------------
Stats for egress port: fc1/6
    TxRt(B/s): 3632
    RxRt(B/s): 2952
        TxB_B: 32
        RxB_B: 32
      TxFrame: 137476
      RxFrame: 137467
       Errors: 0
      Discard: 0
          CRC: 0
-------------------------------------------------------------------------------
Hop 3       Domain In-Port          Out-Port         Speed Cost  Switchname
            111    fc1/6            embedded         -     -     switch1
-------------------------------------------------------------------------------
Stats for egress port: embedded
    TxRt(B/s): -
    RxRt(B/s): -
        TxB_B: -
        RxB_B: -
      TxFrame: -
      RxFrame: -
       Errors: -
      Discard: -
          CRC: -
NOTE: The stats are displayed for the egress interface only

The following example shows how to trace all the links (including equal-cost parallel links) in the paths between all the edge devices in a domain and a switch in which the command is executed:


switch# pathtrace domain 238 vsan 1 multipath
***NOTE ***                                      
 I - Ingress                                     
 E -  Egress                                     
 M - Member Port-channel                         
 * - Fport                                       
...................................................
PATH 1   switch1 switch2                           
Domain   236       235
......................................................
-----------------------------------------------------------------------
HOP 1   switch1(fc1/11)(E)-------(I)(fc1/12)switch2
----------------------------------------------------------------------------------------------------------------------
Interface  Spd(G)  Tx(B/s)  Rx(B/s)  TxB2B  RxB2B  Errors  Discards   CRC   TxWait(1s/1m/1h/72h) FibDrops   ZoneDrops
----------------------------------------------------------------------------------------------------------------------
(E)fc1/11  8.0     84       44       64     64     0       2          0     0%/0%/0%/0%          -          -
(I)fc1/12  8.0     44       84       64     64     0       0          0     0%/0%/0%/0%          -          -
----------------------------------------------------------------------------------------------------------------------
HOP 2   switch2(fc1/3)(E)*End Device
-----------------------------------------------------------------------------------------------------------------------
Interface   Spd(G)  Tx(B/s)  Rx(B/s)  TxB2B  RxB2B  Errors  Discards   CRC   TxWait(1s/1m/1h/72h) FibDrops    ZoneDrops
-----------------------------------------------------------------------------------------------------------------------
(E)fc1/3    4.0     0        0        16     64     0       0          0     0%/0%/0%/0%          -           -
.......................................................................................................................
PATH 2   switch1 switch2
Domain   236       235
.......................................................................................................................
-----------------------------------------------------------------------------------------------------------------------
HOP 1   switch1(fc1/12)(E)-------(I)(fc1/11)switch2
-----------------------------------------------------------------------------------------------------------------------
Interface  Spd(G)  Tx(B/s)  Rx(B/s)   TxB2B   RxB2B  Errors  Discards  CRC   TxWait(1s/1m/1h/72h) FibDrops     ZoneDrops
----------------------------------------------------------------------------------------------------------------------
(E)fc1/12  8.0     64       180       64      64     0       0         0     0%/0%/0%/0%          -            -
(I)fc1/11  8.0     180      64        64      64     0       0         0     0%/0%/0%/0%          -            -
----------------------------------------------------------------------------------------------------------------------
HOP 2   switch2(fc1/3)(E)*End Device
----------------------------------------------------------------------------------------------------------------------
Interface  Spd(G)  Tx(B/s)  Rx(B/s) TxB2B  RxB2B   Errors  Discards   CRC   TxWait(1s/1m/1h/72h) FibDrops      ZoneDrops
-----------------------------------------------------------------------------------------------------------------------
(E)fc1/3   4.0     0        0        16     64      0       0          0     0%/0%/0%/0%          -             -


switch# pathtrace domain 132 vsan 447   multipath 
***NOTE ***
I - Ingress
E -  Egress
M - Member Port-channel
* - Fport
...................................................
PATH 1   switch1 switch2 
Domain   187       132       
......................................................
-----------------------------------------------------------------------------------------------
HOP 1              switch1(port-channel216)(E)-------(I)(port-channel216)switch2
-----------------------------------------------------------------------------------------------
Interface          InputRate(B/s)     OutputRate(B/s)    InputFrames(/sec)   OutputFrames(/sec)  
-----------------------------------------------------------------------------------------------
(E)port-channel216 3393959            640827945          161838662680576     1375239938244608    
   (M)fcip50       292049             55048436           3239                27507               
   (M)fcip51       291539             55052889           3237                27508               
   (M)fcip52       291702             55080573           3239                27522               
   (M)fcip53       278265             52552382           3090                26258               
   (M)fcip54       278291             52561525           3090                26263               
   (M)fcip55       278346             52559754           3090                26262               
   (M)fcip65       291647             55073072           3238                27518               
   (M)fcip66       278491             52584017           3092                26274               
   (M)fcip67       278362             52571056           3091                26268               
   (M)fcip86       278290             52554341           3090                26259               
   (M)fcip87       278426             52587737           3092                26276               
   (M)fcip88       278551             52602163           3093                26283               
(I)port-channel216 640830213          3394016            1375252823146496    161842957647872     
   (M)fcip50       55058685           292105             27512               3240                
   (M)fcip51       55080107           291690             27522               3239                
   (M)fcip52       55097520           291794             27530               3240                
   (M)fcip53       52559881           278311             26262               3090                
   (M)fcip54       52570959           278345             26268               3091                
   (M)fcip55       52571081           278410             26268               3091                
   (M)fcip65       55051714           291539             27507               3237                
   (M)fcip66       52564219           278387             26264               3091                
   (M)fcip67       52562847           278324             26264               3090                
   (M)fcip86       52564931           278345             26265               3091                
   (M)fcip87       52571632           278350             26268               3091                
   (M)fcip88       52576637           278416             26271               3091                


switch# pathtrace domain 83 vsan 70 multipath 
***NOTE ***
I - Ingress
E -  Egress
M - Member Port-channel
* - Fport
...................................................
PATH 1   switch1 switch2 
Domain   144       83        
......................................................
-----------------------------------------------------------------------
HOP 1              switch1(vfc69)(E)-------(I)(vfc69)switch2
---------------------------------------------------------------------------------------
Interface     Spd(G)  FcoeOut(Oct)       FcoeIn(Oct)        FcoeOutPkt         FcoeInPkt          
--------------------------------------------------------------------------------------
(E)vfc69      10.0    165604             153648             697                700                

(I)vfc69      10.0    153716             166276             701                698    



Note

  • In the output, embedded indicates that the respective port is an HBA interface on an edge device.

  • Some of the terminologies used in the multipath outputs are defined in the following table:

    Table 1. Multipath Terminologies

    Term

    Description

    FCIP

    InputRate(B/s)

    The number of bytes received per second on the in port of an FCIP link.

    OutputRate(B/s)

    The number of bytes received per second on the out port of an FCIP link.

    InputFrames(/sec)

    The number of frames received per second on the in port of an FCIP link.

    OutputFrames(/sec)

    The number of frames received per second on the out port of an FCIP link.

    vFC

    FcoeOut(Oct)

    The number of egress FCoE octets on a vFC interface.

    FcoeIn(Oct)

    The number of ingress FCoE octets on a vFC interface.

    FcoeOutPkt

    The number of egress FCoE packets on a vFC interface.

    FcoeInPkt

    The number of ingress FCoE packets on a vFC interface.